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Author Topic: Carina sailboat - my scratch build!  (Read 9989 times)

Hellmut1956

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Carina sailboat - my scratch build!
« on: May 17, 2013, 10:51:32 AM »

Dear friends


as promised or may better said as I have threatened to do, here the report of my eternal build from scratch of a sailboat with long keel based on the plan of the Voilier from a German source. The plan is the copy of a copy of a copy and as such distortions of it have made it necessary to do a lot of rework on the plan to be able to use it. I was quite disappointed when I got delivered the plan that did not consist of more than a DIN A0 sized paper.







This plan used to build the Carina is even in worse shape, as I did not care enough of it when I build the first hull using this plan the sail boat called the Sabrina. Then my son Andreas had to embarque into a school work in its 8th class and so he accepted my offer to build a hull based on this plan. For me the intention was to build a light version of the sail boat, as the first resulted too ambitious.





So the first step in this project for my son was to digitize the frames of the plan and the top and side views. For this he started with good old fashion technique using oil, to make the paper of the plan transparent and a needle and pass the shapes onto coordinate paper.





We used the Excel Chart feature, were the previously recorded digitized values were stored to fix the values that were evidently wrong. A nice side effect of this was, that errors while digitizing the data became evident and could be corrected.

Having done this we used the result to fix distorsions and to ensure the curves were smooth. Then we passes the frames into a CAD package you can get for free, called "Solid Edge 2G Drafting". Here an example:





You can see that we added "ears" to the frames. The reason for this is that we choose the the upside down method of building the hull and all frames had to be placed at such altitude above the base, that the design waterline had to on a horizontal plane parallel to the base.





We than printed the frame images and glued them onto a 4 mm thick wooden plate. I want to indicate, that heavy paper or even better, carton should be used, as normal 80 gr. paper tends to change its shape, when the glue is applied, as it gets wet. This wooden plate used is called "Siebdruckplatte" in German. This king of wooden plate is used to build concrete formwork. It has the advantage to have a surface that is very resistant to mechanical and chemical stress, here the advantage is that it is very brittle. You will see later why this is of huge benefit!





As you might see looking in detail into the foto, I used the zip-principle to glue the ridges onto the frames, 8 x 3 mm cross section.





To ensure the hull would not be distorted during the construction, we glued the ridges, one at each side, making sure the stress would stay symmetrical.





When I build my first hull I was worried about how easy or difficult the glueing of the ridges would be, specially at places like the one shown in the picture, were different shapes come together. But it proved to be no problem. The most difficult one was glueing the second ridge after the one following the deckline next to the stern mirror. The first ridge following the deckline had to be glued vertically, the second hat to follow the large change of the frame shape.





The reason I used pine wood for the ridges, was the grain of the wood. I want to highlight the old wisdom of anyone familiar with handcraft work, that any error that can be fixed early in the work process saves from having to spend 10x the effort to fix it later! So spending effort to get perfectly shaped frames is well spend to save work while grinding. my son had the great idea of taking some images from within the hull to make the construction visible. Next some pictures made from within the hull!





I love this picture as it shows the frames and the ridges glued to them. But also interesting has proven to be the fact that even the filigran shape of the frames was OK and it facilitates the pressing of the ridges onto the frames while glueing them.







Now a picture from the grinding phase of the construction of the hull.





While no doubt it is a tough job, it is also honouring it with the results! excuse me if you consider it not appropriate. But sliding the hand surface of such a wooden hull after some grinding gives a wonderful feeling, some consider as great as doing the same with a woman! Wood is a wonderful material to work with! To motivate myself grinding, I like to proceed, changing from grinding one side until it feels pretty good and than change sides. The result is, that the actual side being grinded at the end feels so much better, that you end up really wishing to improve the other side! Grinding of the hull took nearly 3 weeks!





When the grinding has reached a quality of the surface that seems fine, I like to apply G8 polyurethane varnish, with thinner, using 4 parts of thinner and one part of the varnish. One one side this varnish has the effect to protect the wood from humidity that might come in touch with it if the lamination gets damaged, but in this phase of grinding the hull it has the effect of improving the light reflection of the surface of the hull making irregularities visible.





Remember, I cannot use filler, as i want to keep the grain of the pine wood visible. On the picture you see me working on removing the hull from the base. The frame had been fixed to the bars screwed onto the base, but the glue falling onto it while glueing the ridges onto the frame, made it necessary to use a tool to remove the frames. You can also see how the G8 has changed the color of the ridges, while this is also a prove that the wood is well protected against humidity, as the thinner helps the G8 varnish to penetrate deep into the wood.





Here a picture of the base showing the principle of how I fixed the frames onto it. The planarity of the base is key, as any distortion would pass onto the hull shape being build. So I use the thickest wooden plate available and do reinforce it applying stabilizing wooden frame at the length on both sides.





Here a view from the toüp of the whole hull, just after removing it from the base. You can see, that the frame are already implementing the curvature of the deck, a useless effort, as the frames broke easily due to the brittle nature of the wood used! The weight of this 165 cm long hull was just about 450 gr, including the frames!





Here you can see how the frames got spoiled over time. But this apparently weakness proved to be marvelous! As the frames were so brittle, removing them, just using a tong, grasping a piece of the frame and turning the tong. This way the frames could be removed leaving nearly no trace on the hull!





Isn't this a great result? Such a clean inner side of the hull, that just required a bit of grinding, would make it much easier to laminate the hull from within. But it also reduced the weight. of course I did also apply a few layers of G8 varnish to the inner side to make sure the wood was well protected against humidity! But there are 2 more things I would like to highlight in this picture. One being the fact that I did fill up the front most and the rear most compartment made by the frame with epoxy. And that I did insert at this phase only in the front an aluminium piece in it where the screwed hole was prepared to connect the fixing point of the mast. This way that pont was firmly integrated into the hull structure. later same was done at the rear.


The second point I want to highlight is the lead I am casting into the bottom of the keel. The technique used and that prevents the wooden ridges to suffer from that process is as follows. Fist i just cast a bit into the hull and let it cool. The amount of heat energy of just a bit lead is not enough to endanger the wood. Then, as i add more lead, the already present lead works a a heat sink, absorbing the lead of the later one applied, so that on every step more and more lead can be casted into the hull without damaging the wood.


Here a more detailed view of this.





remember, that on a sail boat with long keel every effort has to be done to have the center of gravity as deep in the hull as possible. Just let me tell you, that the final displacement of the hull allows for a total weight of the sail boat of 29 kgs!





Here you see me laminating the hull with glas fiber and epoxy from within. it is important to mention, that as wood works, to prevent this from making the ridges noticeable when touching the hull from outside, symmetrical lamination from the inner and the external side of the hull is mandatory. i have used 29 grs per square meter weight glas fiber for the lamination, but up to about 100 grs is OK, and you would not see or feel the lamination when touching the hull!





Here the compensation for all those efforts! i sometimes think it would make sense to leave the hull like this, as the color is to my personal oüpinion marvelous! I want to stop here the report to reflect the achievement reached at this point and continue the report as a reply to this contribution!
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Martin [Admin]

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Re: Report of build from scratch Carina
« Reply #1 on: May 17, 2013, 12:37:14 PM »


    :-))
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rmaddock

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Re: Report of build from scratch Carina
« Reply #2 on: May 17, 2013, 01:20:57 PM »

Fantastic work Hellmut!

Great to see somebody trying to be even more hi-tech than me!  I thought I was being clever using 3 Picaxe controlled winches  :o

I'm also fascinated to see that you've poured the lead directly into the hull.  How easy is that?  I've always struggled making plaster casts first and then sand moulds.  When I put the lead in my current project, a GRP hulled sailing trawler, I thought about pouring it straight in.  I'd read that you could - especially if you put the hull in water as a heat sink.  But every body said NOOOO!!!!!!!  If you can pour molten lead into wood then GRP should be able to withstand the same.  Next time I'll be brave enough to try.

Keep posting.  I, for one, am eager to watch your build.  I'm not going to comment on your thread about your workshop as it makes be feel ill when I compare it with my cellar  <*<

Cheers!

Robert.
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Hellmut1956

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Re: Report of build from scratch Carina
« Reply #3 on: May 17, 2013, 02:08:10 PM »

Well, allow me to repeat it. pouring molted lead into a wooden hull is no problem and the hull put into the water would be of no help anyhow, as the wood isolated the heat coming from the molted lead, as a consequence, not working as a heat sink! by proceeding as I described, pouring into the full first just a little bit of molted lead, this first lead inserted into the hull will work as heat sink for later added lead. Just keep in mind, it is a management of the heat energy that is in molted lead. You should never add more molted lead into a hull, as the already in the hull present lead can absorb as heat sink! It is in first degree, not so much an issue of the total quantity of lead within the hull, but of the lead surface onto which you pour additional lead. You want the molted lead to transfer its heat energy as fast as possible to cool down enough not to burn the wood!


As to the electronics! I started it simple. A friend of mine and I came together in my work shop, mounted a mega8 controller vom Atmel onto a board with through holes, an exercise of just on hour may be, connected a display and connected the slots of a receiver, the signal carrying line, to one of the pins of the controller. The ground and positive pole were used to supply the controller circuit with power, just 5 VDC. Than we used the BASCOM compiler, you get it here for free. After just 20 minutes we were able to display the length of the signal being offered to control i.e. a servo. Its called PWM as you well know, that repeats about every 20 ms. Just 10 minutes later we displayed the signal length of all 8 channels. having decoded this way the signals the control stick and switches settings from the transmitter were available to the software and could be used in any way. I can publish a tutorial about this, if there is an interest for this!


Now, a couple of years down the road, I do plan to use a board from NXP called LPCxpresso, here is one source that indicates the cost of this board is just 20.- Euros! This is so inexpensive that I plan to use many of those within my model, as this one comes with a sophisticated quadrature decoder as a built in peripheral, that I cannot just control an home made board with a brand new module from Trinamic, but i also can decode the position data from an magnetic angular encoder, that gives me more than 12 bits of angular position resolution. The wonderful issues with this board is that it comes with an JTAG IF on an extension of this very board, so that a debugger of the also free IDE can debug in real time in the target hardware. But also the IDE from Code Red, recently acquired by NXP, does know the lpcxpresso boards and builds the whole environment, so you do not need to setup the tool chain or the make process.


Additionally the ARM core of this controller, an ARM Codex M3, has, like all ARM Codex products in the market, the same application programming interface, short API, to use the peripheral modules on chip! So you do not need to worry to write the drivers for those peripherals. On top you get code samples for the use of all peripherals, which being reused just need to have the parameters adapted to your needs! So for somebody to start to dwell into the wealth of using own micro electronics circuits, starting i.e. with an Atmel mega 8 to open the boxes perceived as black boxes and the tutorial I mentioned, can start to combine those like lego stones to build its own function!


A later step is i.e. using the Arduino boards with the wealth of so called "shields, expansion boards to add functionality, i.e. 2.4 Ghz communication via XBee Pro, or al a later stage data communication via cellular phone data communication. I am waiting for a good 3D camera of the size of a USB stick, I am sure this will come by the time I need it, to be able to operate my sail boat by "First Person View", short FPV frm looking out of the head of the skipper on board!


Combined with this is the idea of building my own control remote around an Android Tablet, which would still have the control sticks and a reduced set of switches and rotating controls, as we know them from todays transmitters but assigning the function to them dynamically through the Android App that would implement the GUI, Graphical User Interface and the interface to the external hardware via an USB I/F. Such a unit would allow to connect FPV goggles to it and as we all know from using Skype, display the content of the video coming from the boat via the cellular phone video stream! i believe 2.4 GHZ in the midterm will die again, as the performance and real time abilities of the data com via cellular phones improves. For us, the builders and skippers of model ships, real time is much less critical as it is to the flying part of model building!
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john44

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Re: Report of build from scratch Carina
« Reply #4 on: May 17, 2013, 02:33:32 PM »



  But every body said NOOOO!!!!!!!  If you can pour molten lead into wood then GRP should be able to withstand the same.  Next time I'll be brave enough to try.




Do not use water as a heat sink, if the molten lead melts through the grp hull
you will get burnt from its explosive reaction to the water.
that is why everybody said NOOOO!!!!!
so please don,t be brave enough to try it.

john
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Hellmut1956

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Re: Report of build from scratch Carina
« Reply #5 on: May 17, 2013, 02:43:31 PM »

At least not with water outside! What is GRP?
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Hellmut1956

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Re: Report of build from scratch Carina
« Reply #7 on: May 17, 2013, 03:40:08 PM »

Then probably pouring molted lead into the GRP hull, being very careful and starting with a small quantity of lead will not be a problem! But putting the GRP hull into the water has no benefit at all! As boards made with GRP core are used for electronic circuits and those boards have no problem being put into a reflow oven at around 250°C to solder electronic components onto it with soldering paste!


But I cannot see why putting it into water should be specially dangerous! may be because if you pour a huge amount of lead into such a hull as the very first quantity to be inserted eventually water coming into the hull might get into gaseous condition. But some like to pour lead into water to see the future with no risk coming from the lead, but from the foolishness of believing in it!
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Re: Report of build from scratch Carina
« Reply #8 on: May 17, 2013, 04:02:19 PM »

Hello Hellmut,
What weight of lead did you get into the keel, how deep below the waterline is it ?.
John.
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Hellmut1956

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Re: Report of build from scratch Carina
« Reply #9 on: May 17, 2013, 04:20:59 PM »

The lead at its deepest point is 25 cm below the flotation line. As of now I have introduced about 10 kgs! When I come to that point in this report you see that I am putting a lot of weight below the waterline level! I.e., 12 LiFePO4 battery cells, each about 450 grs weight! But as you can see from the size of the sails I plan to support, the surface of the sails being about twice the size you find on models of the J-Class! Of course, if you would imitate the relative size of the Endeavour i.e. that sail surface would even be slightly larger than that of my Carina!


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Hellmut1956

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Re: Report of build from scratch Carina
« Reply #10 on: May 17, 2013, 06:36:23 PM »

I will continue now with the report!


Sometimes small issues have great consequences! My wife, even as she is totally not technical, did ask me why I didn't make the complete deck removable. as usual, going out into the countryside with my dog I started to think about it and decided to make the complete deck removable. Now I am, what germans call the belt and suspender person. i want to make sure I am on the safe side and so I developed my concept to make sure no water would come into my hull! So I decided to combine 3 elements:


1. A labyrinth sealing made out of of two nested aluminium U-Profiles
2. A mechanical fence where ever possible
3. A rubber sealing







Lets started recapitulating the starting condition! A 5x5 mm mahogany strip follows the deckline of the hull. Along this one, fully around the hole deckline of the hull a U-Profile, made out of aluminium had to be glued into the hull, open to the top to receive water that might slip through the external rubber sealing not yet installed.





Watching this picture you can see the complete ring of aluminium glued into the hull. This definitely will stabilize the hull shape and make it extremely stable. You can also see at the rear end, on the top of this picture the mounting of a large Hitec servo to operate the rudder. Well, as of today, I plan to replace it by a small stepper motor and a large belt pulley, because this way I have more torque and it will operate without making any noise! To both sides in the middle section you can see brass colores L-profile aluminium bar screwed to an about 25 cm x 5 cm x 5 mm aluminium bar which was glued against the wooden hull. On the upper side I did make 2 threaded holes, M3, as the basis to have the pulling force from the shrouds conducted into the hull structure. I have put a bar between both sides with the hole for the mast, having its position well defined this way, based on the plan of the ship! But you can see one more very important thing, the first crossing section of the labyrinth sealing with 2 opening already made. by the plan the deck has 4 structures on the deck. These 4 structures will also be removable and so the labyrinth sealing also has to circle them!





A more detailed picture of the central section! Here I want to highlight, that because no glue did really work all connection of aluminium parts are made using screws to support the union of the parts connected also by glue, because the glue also helped to seal those unions! At the bottom you can see 2 aluminium bars glued into the bottom of the hull. Well the left overs over solutions thought of earlier and later replaced by what I do consider better approaches. here a view from the rear:







Now a total view of the labyrinth sealing nearly completed, the hull side of it, with one of the deck structures plugged into its opening!





You can also appreciate how I was continuing the work to improve the contact surfaces outside the aluminium ring, where a rubber sealing band glued onto it and the deck pressed against it, will be the first line of defense against water entering the hull this way!





A detailed photo of the front section, also with one deck structure plugged into the corresponding opening. the same for the rear section:







Now a detailed photo of the front of the hull with the aluminium bar and the threaded holes into it to connect the fixing point for the Forestay and the screw to press the deck onto the hull contact surface to make the rubber sealing work!





The same for the backstay. The surface will still be covered with veneer of mahogany wood.





Next a detailed picture of the contact surface on the left middle side. You can see another of those techniques that proved to be inadequate, to press the deck onto the contact surface of the hull. I did plan to use and did install those hexagonal spacers we all know from our PC case used to mount the motherboard. I thought that by embedding their base into glue this would prevent those spacers from rotating. Reality proved, that some did rotate anyhow, so I had to drill the screws out to remove the mounted deck. Now, where the surface of the deck  was not yet build, that was not a problem, but i will show later that I came up with a different solution.


Similar detail from the bow section:





Now the picture of a drawing that shows how those spacers fit into the concept of pressing the deck onto the hull!







Finally a picture that shows the central section of the removable deck and how it will be pressed onto the hull. Just 1/3 of the width of this mahogany strip will be left when sanded to match the hull surface below! The rubber sealing will be glued where the aluminium from the deck makes contact with the surface of the hull. As I wrote before, my first line of defense against water penetrating the hull!



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Hellmut1956

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Re: Report of build from scratch Carina
« Reply #11 on: March 11, 2015, 08:20:27 PM »

I will try to get this thread closer to today. Taking into account the long time that passed since the last time I did contribute something to this thread I want to emphasize to wwhat this project has evolved to. When I  lost my job in 2000 and it became evident that I would not be hired again this project of building a sailboat model from scratch became a platform which got me in touch with the most diverse technologies and following them has become over now one decade my source of having an organized life, a day full of planned activities and a great comfort due to the challenges it presented to me and dealing with those a source of fascination and positive force in my life, on top of my wonderful family I am a happy person. As I continue to present my activities around this project you will either be as fascinated about it, of seeing it as science of another world applied to our hobby as some others call it or simply stating that I am crazy (the last being highly probable).   :-))


But let us continue!


Being at a pond site during meetings of german hobbyists I got to love to see what effects light have on the beauty of a model navigating by night. Thinking about it I came up with the following goal.


1. I would install 4 Cree high performance LED beamers under deck and would have them, dimmable by radio control illuminating the fock and the main sail of my boat.





Here you can see the 4 LEDs from Cree.  On top of each there is a plastic diffuser that makes the appropriate beam. One peculiarity of this very high performance LEDs is, that they come on a PCB with aluminium core, where traditional PCBs have a fiber glass core. The reason for this is the requirement to diffuse the heat that is generated when operating this devices. Now, those LEDs will be mounted on aluminum plates that diffuse the heat into the aluminium structure of the removable deck. Similar to what we know from CPUs in PC motherboards, a heat conductive clue will ensure best possible heat conduction into the aluminium structure in my boat. Convective heat dissipation will not play a role with this LEDs directly, as mounted between an opening below the deck surface there will be no air gap on the top side! But you will see later that PCBs with aluminium core will play an important role!


The next goal I did set myself for the illumination on my model for night events, be it navigating or on display were light sources that illuminated the deck and the companionways were people would enter into rooms below deck so that nobody would stumble over the steps indirectly and by being able to dim it by R/C control I could dim between minimal light intensity during night navigation and maximum during parties in the harbour! So first think I did was purchasing standard yellow LEDs that accept up to 20 mA of current, build a small circuitry with variable resistances so that I could control the flow of current and the tension applied to an LED. This was a great disappointment as the light from this LEDs had so little intensity that illumination for a party in the harbour would be a joke. I purchased 200 of those LEDs at ebay for just about 10 USD including shipment costs. Here some pictures:







So what I did first was to drawn a picture of a single PCB for an LED, as those were surface mount devices. Then I put a lot of the on a single peace of paper and passed this by printing it with my Canon printer:





This was printed with an inkjet printer the darkest opaque possible way on a sheet of paper to review the result and to measure if the individual PCBs had the right size!


As I do make my own PCBs I had build myself a device to expose films with ultraviolet light onto positive photosensitive raw PCBs using a face tanning device purchsed for just 1 Euro at ebay.






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Hellmut1956

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Re: Report of build from scratch Carina
« Reply #12 on: March 14, 2015, 06:14:08 PM »

Hi friends, while I will continue with this report shortly, I would like to open a new thread to present a subproject closely related to this one! My sailboat Carina, even as I did now know about J-class sailboats from the beginning of last century and specifically the Endeavour, I want to implement on my Carina the s sheet control system capable of implementing in my model what can be seen from the original Endeavour on the following picture:





As you can see the sheet goes from the deck to the boom of the main 6 times. On the Carina both the main and the foque sail have a boom and will be handled similarly. The following drawing  shows what are the 2 booms on my sailboat:





As the distance between the vertical axis where the boom rotates and the point where the sheet connects to the boom of the main on my Carina is 1 meter, the distance the sheets have to reach when the boom is in a 90° position to the hull centerline is the square root of 2 or 1.4 meters. The sheet covering this distance 6 time gives


6 * 1.4 = 8.4 meters


This is the change in length my sheet control system has to cope with. None of the existing methods to extend the length by which the sheet length can be changed in a hull of 1.65 meters length works. So I have decided to design a system using a stepper motor as a winche and relatively complex electronic system to implement y sheet control system capable of supporting the change in sheet length that I require, while ensuring the available sheet length at any point in time is just adequate for the poom position at that time. Her a block diagram showing the electronic components that will not just implement my sheet control system but also be able to support all the other stuff I have planned for my model Carina:





I will introduce you in detail to what this block diagram presents further ahead of my report from scratch, but just from having a glance on it it looks pretty complex! Reflecting over the implications of the design envisioned I could identify a couple of issues and could refine the design to take those issues into account. But experiencing that while reflecting over the system I came up with aspects that required additional things to be adapted I came to the conclusion that the chances are high that I might still miss some of the issues. Also, I have received a couple of warnings and advices from naval modelers that raised issues that, while I believe my system could handle them, still are worth to be analyzed. Also reflecting over the implementation of the system and due to the capabilities of the stepper motor control components from a company called "Trinamic" it became evident that a lot could be accomplished to achieve a dramatic increase in energy efficient operation of the system. It also became evident that due to the many interdependencies inherent to my system experiments could not really completely to find the setup of parameters that would reach an optimum energy efficiency possible. In this context I came across a methodology called "Design by Modeling" that could be used to verify all the multiple aspects of my sheet control systems, understand the real impact of the advices and warning I have received and to achieve the energy efficiency possible. So the thread I will open deals with what I do considers the design methodology of the 21st century and which I love to learn and apply to our hobby. I run into scepticism and mental barriers in the naval modelers community already trying to promote that loosing the respect and fear on relatively simple electronics, self designed and build electronics could open a whole new world into what is possible in our models. Believe me, what is required to just jump start into using self build electronics in our hobby is orders of magnitude simpler and less demanding the skills of naval modelers than those techniques we can admire in the reports i.e. in this forum. Well, the methodology "Design by Modeling" is quite a bit more demanding than just using self build electronics in our models, but the possibilities it opens to our hobby are really tremendous and the potential to use it in our professional life opens many doors to young hobbyists and gives the mental challenges for those of us with a couple of more years accumulated on our accounts!
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Re: Report of build from scratch Carina
« Reply #13 on: March 15, 2015, 10:10:04 PM »

@Helmut1956:
That is an interesting concept for the sheet control and has a lot of potential


As you have noted, you will need to transport and manage considerable lengths of line. Due to the mechanical advantage gained from the pulley system you should only need comparatively small winches for the job.


The main issue I see is how to maintain tension on the lines so you don't get awful tangles below deck.


Looking forward to progress on this.
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Re: Report of build from scratch Carina
« Reply #14 on: March 15, 2015, 11:17:29 PM »

@mrpenguin: Greetings from the other side of the globe! The reason for the sheet control system is exactly what you are asking about. it is not just to prevent tangles below deck, but also above deck! If you have read my thread regarding the sheet control system, which I confess is pretty hard and extensive stuff and its focus is more oriented towards my learning and applying the methodology of the design by modeling. As you might have read, I have started to explain what I was trying to achieve applying this methodology and what problems and issues related to the sheet control system implementation let me believe it to be justifiable for me to apply the methodology of design by modeling, finally deciding to go for the tools from Wolfram and the modeling language Modelica. So the explanation of the very basic goal of this sheet control system got hidden under all this other data!

The main objective really is to keep tight control of the amount of sheet available at any time to prevent the awful tangles you addressed. The way the sheet control system achieves this applies only to sails that do have a fixpoint around which the boom turns. By using the magnetic angular sensor that basically works as the picture indicates:




The sensor provides to the controllers quadrature encoder peripheral the 3 PWMs called ABI that informs me about 512 possible angular positions of the boom over the 90° from aligned to the hull center line to the perpendicular position shown in the drawing below:





In this drawing the thin lines represent the sheet or lines as you call them for the 90° position of the boom. It is now simple to find out that for every and each of the 512 angular positions between 0° and 90°, or every 90°/512=0.1758° I can have a table that defines to which position of the over a million that the stepper motor has for its 21 full 360° turns that supply up to 8400 mm of line length it has to move to supply just the amount of line length required for this angular position of the boom... The result is a line were there is never more line available than it requires for the boom in its actual position!


Lets see, simplified not to compute length of the hypotenuse that is the length of the line to the boom for every one of the 512 posible angular positions sensed by the magnetic angular position:


200 Full steps (per 360° full turn) * 256 Microsteps for each fullstep * 21 full 360° turns = 1,075,200 positions the stepper motor can be in over the full 8400 mm it can change the length of the lines!


1,075,200 / 512 angular positions of the boom sensed = 2100


The stepper motor would move 2100 microsteps to adapt the line length for every and each of the 0.1758° the boom angle can changed and the sensor sense. To store this in the flash memory of the LPC1769 controler I plan to use this just requires 4 bytes per data item * 512 entries in the table = 2048 bytes, nothing! Another way to get a feeling about how precise my sheet control system can control the length of the lines depending on the angular position of the boom is to translate those 1,05,200 possible positions of the stepper motor to the change in length from one of those positions to the next:


8400 mm / 1,075,200 Stepper positions = 0.08 mm change of the line length from one position of the stepper motor to the next! This is by far a higher resolution of the control of the line length then it could make sense. But due to the way the stepper motor operates, that is the given line length resolution available!




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mrpenguin

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Re: Report of build from scratch Carina
« Reply #15 on: March 16, 2015, 01:38:02 AM »

@Helmut1956:
Thank you for the detailed explanation. I think I follow what you are planning. The angular sensor on the boom will certainly provide the feedback loop necessary to manage the stepper motor.

As I understand it, you will be using the wind pressure on the sail to haul the sheet line out through the blocks. While this should be fine in a reasonable wind, this may perhaps cause some grief in light conditions as the boom is at a considerable mechanical disadvantage in trying to get the line released from the winch out through a fair lead and through the multiple blocks.

Watching with interest. I have attempted to manage large lengths of line in an RC genoa application, and it is full of problems. 
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Hellmut1956

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Re: Report of build from scratch Carina
« Reply #16 on: March 16, 2015, 12:46:41 PM »

As I wrote, I have been made aware of this issue and it is one reason why I have started my initiative of applying the methodology of design by modeling and why I will start  developing a model for the line with the block, a model that will be crucial to respond to this! I was warned, that as it is the job of the sail to open and as a consequence pull out the lines to make this possible the use of the methodology of the design by modeling will help me to simulate the behavior and to get a sense about how much wind is required, or more precise, how much pressure the wind has to exercise to be able to open itself while pulling the lines.


One think my sheet control system ensures is, that the stepper motor that controls the length of the available lines will closely follow the move of the boom and adapt the available line length so that all the pressure on the sail has to do to pull line as it opens is to apply the force required to overcome the friction of the lines across the multiple blocks and through the tubes in which the lines are led as they go under deck and to the drum controlled by a stepper motor. It is my believe that this friction will not really impact the move of the boom as it requires very little force to be applied by the sail and its boom on the lines.


It is even more to consider, first from the positive side! When the sail turns under very low wind conditions, does it really matter if the need to pull the lines through the blocks limits its free movement? I believe not. Can this be a reason to render the sailboat model inoperable? I specifically say that I do guess no! Why? Well, if the wind is so slow that it does not generate the pressure on the sail so that the boom is unable to pull the free lines through the blocks it is hard to imagine it will be able to move a 29 kg sailboat model anyhow? Also such a slow indo can not impose any danger on the sailboat itself!


Now the critical side! Less then the mechanical friction that needs a certain amount of force pulling the lines via the boom through the blocks an eventual electrostatic tension building up between the line and the tubes it is passing through while under deck! This electrostatic buildup can prevent the fee sliding of the line through the tubes much more than the effects of mechanical friction through the blocks! My investigations in the Internet seem to indicate that it is worth to plan to have the lines wet by having a certain amount of water in the case of the drum so that the lines on the drum get wet when they are there. Adding a bit of dishwater detergent into the water within the case of the drum is said to prevent such electrostatic tension build up!


Finally, give me the chance to help you with your problems with reading any part of my report of the build from scratch. I would be pleased to help you by trying to repeat and to make it more readable. i have already taken the advices to frequently ad empty lines within my text and to split my replies more often to reduce their length and to deal with each topic in a single reply. i hope this reply is short enough so that I do not have to split it? if it is too long just tell me and I split it!
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Re: Report of build from scratch Carina
« Reply #17 on: March 27, 2015, 01:09:44 AM »

I have initiated activities to start modeling of my sheet control system. For this I am combining a number of tools and sciences and I have purchased an important book, 125,- Euros required and purchased a software tool called "Berkeley madonna! Lets repeat to prevent misunderstandings. I am learning and will no start to apply some of the issues I have been studying a bit over a year for the strict objective to design and implement a sheet control system concept I have been working on defining it.


I believe it is right to state that for the activity stream I am convinced will take me at least one to two years is based on 3 things:


1. A modeling scheme called Modelica and that in the literature is specified as:
    An object oriented, equations based modeling language.

2. It applies a methodology to represent complex dynamic systems.
   The tool that makes possible in a graphical environment to define the magnitudes and flows and the formulas that apply on them is called Berkeley Madonna. I had learned about the existence of this tool from video lectures from professor Werner Maurer, who used it to graphically describe the aspects while teaching the language Modelica.

3. I found out about activities taking place in the community of people working in physics, this called System Physics that combined all 3 aspects briefly listed here to teach physics.

Now having the System Physics science to introduce physical aspects of relevance in my sheet control system in a way and structure that matched the methodology used in the science of Complex Dynamic Systems and the proper tool to document and to put into relation the diverse aspects I had been identifying while reflecting about my sheet control system during my walks with my dog in the local countryside, Berkeley Madonna and that all of this fitted into the way the language Modelica required, linked by lectures available as videos in the Internet i decided to start implementing!

So I thought about what would be simple enough to model and at the same time valuable to learn about aspects that are again and again raised by well meaning and competent reader of my contributions, for example mrpenguin here on this thread on march 16.

I decided to model a single disc in a bloque as there are 7 of them distributed over 6 blocks that make up the pulley through which the lines go from the boom of the main and before they disappear below the deck surface. Its the picture from the Endeavour that I use again and again.

I will continue tomorrow!
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Re: Report of build from scratch Carina
« Reply #18 on: April 01, 2015, 11:16:11 PM »

I just reviewed the replies you have been so kind to make to my thread about stepper motors. Even then the technicalities of the subject were pretty demanding. Consider that I have lost my last job as an employed worker about 15 years ago. Add to this that my health has now for a couple of times got me a step from passing and that so my studies and my research in the context of building my model sailboat Carina now are even working as a therapy. During those couple of times my heart stopped beating I have suffered damage to my grey cells in my brain. The effect was and is, that I have problems to keep concentrated over longer periods of time and i tend to forget terms that I need to research to find them by using translation tools in the Internet, as in one of my 3 spoken languages I usually still remember the term I am looking for. Now exercising that muscle placed between my 2 ears by doing this research and study work has helped to improve at least my ability to stay concentrated. Now the consequence of all this research and studying is that in all those areas I work, I am a beginner. But over a decade I spend with my project on building the Carina I guess I can say that i have been getting deeper and deeper into the fields of interest. So was the thread about stepper motors considered tough from some of you, the topic I am dealing right now is much, much tougher. But at the same time it opens the doors for a deep understanding of physical properties and how to model, simulate, verificate and optimize what I am dealing with.

But it is really so, that it is closely linked to our hobby, the naval modeling and it is definitely closely linked to my project of building from scratch my model sailboat the Carina.

I am really sad if real experts that give me most valuable recommendations, warnings and advices some times are not willing to accept that it is my objective to spend the time before I pass or before my mental, physical or economical abilities get too limited, to work on the project and not on finishing it! It is even sadder when some move away feeling that it is worthless to give me advices! Those inputs I do highly value and they help me to get aware of issues I had overseen or confirm issues that I am aware of.

So please, continue to give me advices, to criticize what you consider worth to criticize or simply to ask for explanation of what is not clear to you. There is no greater way to learn then trying to explain something to somebody! I felt I have to write this and i hope you can forgive me for sharing with you topics that might be far off of what we naval modelers are usually dealing with. But one experience I want to share. Neither electronics or other technologies are generally justified to intimidate the modeler. We naval modelers to wonders in the many technologies that are applied to build our models. Electronics is really not intimidating! It is more a perception we have in our mind that we kind of fear electronics and as a consequence bloque our minds from getting into the subject. About a decade ago a friend of mine and myself decided to make a tutorial that in small and simple steps which each leads to an experience of accomplishment, to make an experimental board starting from a diagram of an electronic circuit and building the hardware using through hole PCB and programing a microcontroller. In this simple tutorial the ones that made it learn to read a diagram, build a hardware and use short programs to get the building blocks out of which most of the electronic stuff we use in our models can be self build and adapted, just by combining those blocks in the proper way. But as it does in sanding a wooden hull, it requires perseverance, swear and blood to have the perfect sanded wooden hull! We naval modelers usually have the perseverance required, so the only other road stopper is the intimidation we have in our minds when dealing with electronics!

Well, same in a certain, but a bit more abstract way, this also applies to the methodology of design by modeling. It is so, that when you enter into new fields were there is no experience in the community, here of us naval modelers, than to develop the understanding and knowledge to be able to make a tutorial that allows others to follow the road easier, first demands a lot of learning to find the proper way.

Using the modeling to generate a virtual description of something we want to use in our naval models first, at least with me, made me run into the barrier of mathematical skills! Nearly 4 decades have passed since I finished high school with an excellent result in Mathematics. But for decades make your skills erode if you had not been using them regularly. mathematics and the way of teaching and of applying it has also had dramatic developments in this period of time. I would dare to say that just about now the 3 pillars for applying the methodology of design by modeling in our field of naval modeling have reached a maturity adequate to be applied and the tools required have matured enough and the license conditions to acquire such tools have developed to be used legally by aficionados like ourselves!

Thinking about how to introduce you to this 3 pillars shortly mentioned in a previous contribution, I have decided to do so by trying to link it as close as possible to my first objective, a sub project that will model the pulley as seen on this picture:




This pulley consists of 6 blocks with 7 discs in them. The sheet embraces every one of the 7 discs in a different angle. 3 of those blocks in the pulley are connected to the boom of the main. The one at the rear edge seen in the middle, is connected to the boom kind of directly. The 2 lateral blocks are connected to the boom by being on sliders that can move on a rope, each rope connected at 2 places on the boom. Finally the sheet goes through the pulley receiving the pulling force from a boom trying to open via the 3 blocks connected to the boom an the sheet goes to the front of the deck on both sides of the deck to disappear below the deck. manually operated winches under deck were turned by crew members there.

I have decided to start modeling a single of those 7 ones in the pulley. So later those models will be instantiated 7 times, once for each of the 7 discs used in the pulley. i am not sure as I am not a native english speaker if everyone knows what instantiation means. The model is like a product line of discs in a model retailer shop. Parameter values define what is a specific disc. So creating a model of the disc as used in the blocks of the pulley is like going to a shop and looking at the discs offered. I need 7 of those discs, each with a special diameter, each will be embraced by the sheet in the pulley by a different angle. So taking 7 discs means that I do create 7 copies of the model.




Here would be an example of the model of the discs. As you can see on the picture you can define the diameter of a disc by setting the proper value for "D". You con set the diameter of the bearing and if it is a ball bearing or if it is one were disc and axis slide. You can define the angle "Beta" that describes what angle the sheet is embracing the corresponding disc. You can imagine that each one of the 7 discs in the pulley will have and can have its own set of values for those parameters.


So, if you make yourself aware that there is no reason to be intimidated by the subject, then the last picture is easy to understand and to understand that those parameters would be different for each of the 7 discs build into the 6 blocks that can be seen on the picture from the Endeavour could also not be considered difficult or intimidating, right?


Now lets move to the rope on this last picture! The rope is the black line that gets on the disc on the left side and leaves the disc on the right side. This rope is the sheet that controls the sail position of the main! Now it is our every day experience and knowledge that a rope can only be dragged! This means that a drag force applied to the rope would be in the same direction that the rope has. The rope would follow if the drag changes its direction! This in consequence would twist the block in which the disc is. A good example for this to happen is when the sails boom starts to turn.

Now lets take a look at the read arrows in the drawing. The first read arrow on the left side is trivial, right? It is the force that pulls the rope when the boom of the main sail wants to open more, means have a greater angle between the center line of the hull and the boom!


Lets now take a look of the red arrow on the right side of the disc on the drawing! We can basically see what really is the purpose of a disc in a pulley! The rope has changed its direction by the angle "Beta" and as we are still talking about a rope, the force is now in the new direction of the rope due to the disc! Nothing fancy, right! You have surely heard about actio and reactio! For every force there is another force of the same value, but the opposite direction! Well, the red arrow on the right side is exactly this! It has the same value and its direction is still the one the rope has! Just happen to be that the disc has changed the direction of the rope and to the force has followed the direction of the rope! Obvious and simple, right!


Now it happens to be that between the rope and the disc there is friction. Lets not go into details, just obvious to anyone, there will be some kind of friction between the rope an the disc and the disc and the axis on which the disc is mounted. So this helps to explain the equation "F + ΔF"!


Red arrow on the left has the same value as the red arrow on the right!

Fleft+ (Fright + ΔF) = 0

The directions of both red arrows are opposite direction, along the rope direction, so adding them equals 0!
ΔF represents the friction in the disc! So the Fright is smaller by value than the force Fleft by the amount of loss due to friction in the disc. So when the rope gets to the next disc in the pulley on this next disc the Fleft on the left side of this next disc will be smaller exactly by the amount lost as friction in the first disc the rope passed. And so on until the 7th disc in the pulley has been passed by the rope. The direction of the force Fleft on the next disc is opposite direction to the one on the right side of the first disc due to the same principle of "actio and reactio"!

So you can imagine that having an equation that allows to compute the friction in the disc and its block would some up after putting the 7 instances of the model of the disc connected in series and having the friction in each of the seven discs computed I would have as a result how much loss of pulling force the rope has going through the pulley! So if I choose the first force
Flefton the first disc such that after deducting the forces loss due to friction in the 7 discs of the pulley I would know at which force the boom pulls the rope the result would be eaten up completely by the friction! Or to say it in other words: Any pulling force of the boom larger then that value would enable the sail to open!

I have the tendency to want to stop here, but I want to finish just mentioning the third red arrow pointing to the center of the disc! This force FN is the force resulting from the tensión of the rope embracing the disc! As you can well imagine this tension depending force impacts the resulting friction force lost in the disc and the block! Next time I will go into it!
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Re: Report of build from scratch Carina
« Reply #19 on: April 01, 2015, 11:51:47 PM »

HI Helmut,

Interesting start to a concept and I like  your reasons .

May be this site would help you with the 'English' terminology for parts and the loads involved.

http://www.technologystudent.com/gears1/pulley7.htm

A question which caused me to query the photo of Endeavour when I saw it is... why are the attaching the first two sheaves on what I would call a blonding wire. This is because it is like the tight rope used by Blondin to cross Niagara Falls , and other places.

In rigging work this is a poor method of imparting load supports as the pull at each end is very high and not actually calculated as the angle changes so erratically with load.
To hold the boom with these would be prone to problems in my view and I notice that there are 2 looped fixings around the boom , adjacent to the area the blocks are lying in. These, I would imagine, were a safer connection. A thought, as I write this , is that when running free, as we call it, with the boom out at a near right angle to the centre line of the yacht, the boom is not subjected to a side load but a length crushing load instead.

I must say that I did open the barrel like construction of a long gaff sail boom on a 65ft Dutch barge, due to glue failure and 60 miles of running and gybing down the east coast last summer. There was no failure, but when we dropped sail  and started to fold it away we realized we could see through the lathes the boom was constructed of. There were several bands for block attachment places which prevented total explosion into parts.

Regards

Rod
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Re: Report of build from scratch Carina
« Reply #20 on: April 02, 2015, 07:54:01 AM »

Hi Rod


You are exactly one that kind of readers that are of big help to me! The site you refer to is great and I will try using the terminology shown there.


First if I had understood you correctly the connection between the rear and the 2 other sheaves are to say the least critical. On my model I plan to attach the rear sheaves in a more solid anchoring in the boom. With a a robe as shown in the picture from the Endeavour the rope works like a saw and would cut the boom shortly!


The other 2 sheaves which are connected to a glider that can move along a rope that is connected to the boom at 2 locations could be a way in those days to distribute the forces over the boom? That 2 ropes I would connect their ends to the boom in a similar way as I plan to do with the rear sheaves! As the boom will contain a carbon fiber tube around which I will place a construction to have it look similar to the original. Right now I have not resolved finally if the boom will be like it can be seen on the photo or have a triangular cross section as shown in other pictures and used in models!


To the efforts to which the boom is exposed to and to which the pulley is exposed to I believe I have not correctly understood you and this is the reason for this drawing:





Allow me to use this awful and simple drawing to address what I have understood of you reply. The bow of the hull is on the right end! I once made this drawing to present how the rope goes from the deck to the boom with the boom being at an angle between 0° and maximal 90° to the center line of the yacht.

The rope with the boom in a 90° position will have a 45° angle between the boom and the center line of the yacht. But there is also an effort to be expected resulting from the rope and the boom touching the surface of the water! The blocks with the sheaves also add another important element of friction by the contact between the rope and the lateral faces of the wooden blocks.
The wind, when blowing into the sail in a 90° position of the boom generally can be expected to come from the rear and so pretty perpendicular to the sail surface. The effort on boom and pulley, different from I understood from your writing is not longitudinal to the boom, but in a 45° angle worst case!

I plan to find a source in the Internet to compute the pressure on the sail from the wind. This should be based on wind speed, angle the apparent wind direction has to the sail and the geometry and dimension of the sail! I hope such a source will handle properly the 2 effects of the wind on the sail. One is the pressure the wind applies to the sail, the other is the one coming from the lift it generates. Once I do find such a source I want to find an adequate simplification so that the calculation are not too heavy.

I expect this computation rules will give the resulting pressure and lift on the sails center of pressure. I do plan to split this force into a vertical, parallel to the mast and an horizontal parallel to the boom. Using a proportionality based on the distance from the point where the turning axis of the boom is I want to distribute this forces so that I can get  the load the exercised on the 3 sheaves where the load is passed to the pulley! As shown on the site your link points to this is passed accordingly from each of the three sheaves to the rope.

Finally I want to make reference to the "erratic" changes of the load direction that can be expected while the boom is changing its angle. As I have shown earlier i do use a magnetic angular sensor of pretty high resolution to keep track of the angular position of the boom. I will be having the angular position of the boom monitored at an acceptable rate available to the software controlling my sheet control system. For the simulation I will be detecting and analysing the critical conditions identified so far and may be more ones to be known about later. The initial challenge is to find out what amount of wind speed is required at least so the sail can open against the friction. I also will have a rich portfolio of parameters available to find out make able settings that lead to the amount of wind speed required to overcome the friction as low as possible!




I want to introduce you to an important tool i am starting to use to model the pulley. The picture is a snapshot from the Berkeley Madonna tool I use to establish the scenario impacting the modeling of a single sheaves! The tool comes from the people applying the complex dynamic systems modeling and started to develop it in the financial sciences.


I will continue in explaining it at the next contribution!
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Re: Report of build from scratch Carina
« Reply #21 on: April 02, 2015, 09:26:20 AM »

Please, do, keep the postings coming! It's fascinating to read about your approach.

Andy
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Re: Carina sailboat - my scratch build!
« Reply #22 on: April 02, 2015, 11:52:11 PM »

Hi Helmut

I have been thinking more about those sliding blocks and through this drawing realize that it is probably to move the effort to about halfway along the boom when running.
It is seldom possible to put the boom out to 90 degrees more likely 75 , as otherwise the boom will hit and rub on the mast shrouds.

Similarly it is seldom that you steer to allow the wind to be dead inline with the boat as accidental gybing can occur. So with the sail out to port the boat would be steered  with the wind coming just over the starboard side of the stern, this allows small wind changes to be safely handled by the helmsman.

Rod
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Re: Carina sailboat - my scratch build!
« Reply #23 on: April 06, 2015, 08:57:40 PM »

Hi friends, it is fascinating how I really do benefit from comments made by naval modelist that do consider what I am doing totally unnecessary! Reading carefully what they write and their arguments is a valuable contribution to generate my awareness of aspects I might not realize! One wrote that of what help would be a static calculation of the loads, if the wind suddenly opens the sail this an kill what ever static dimensioning I might have calculated!


Well, that is wrong assumption made that the modeling is a static view of the system! Lets go step by step, because it is worth to later better understand when i present details of the 3 pillars on which my modeling is done! The Berkeley Madonna Flow Chart I presented above expressed in the terms of the third pillar "System Physics" might explain!


A mechanical system is modelled and explained and calculated in System Physics terms as a recipient containing momentum and the flow into and from the recipient is called momentum flow! lets look into it as it helps to explain!


Momentum = Mass * Speed


So momentum is a recipient containing momentum which is the result of multiplying the mass by the velocity. Often visually a picture from the dynamics of fluids is used and the surface of the recipient represents the mass of the object and the amount of fluid it contains, the fill level is the speed.











So next the formula for Momentum:


Momentum = mass * velocity


The flow of momentum is force and this is what fills and clears content of the recipient, Momentum. Force can be expressed by the following formula:


F = m * a


Force = mass + acceleration!


This 2 formulas that express the Momentum in a mechanical translational system are both not static, but dynamic! So the model will therefor not only be able to find out what windspeed blowing at a certain apparent angle into the sail is required to equal the friction in the 7 sheaves. So any wind faster then the one that equals the friction at the respective angle flowing into the sail will be sufficient to overcame the friction and so open the sail.


But what also is evident is that the friction between the rope and the sheaves is dependant from the tension of the rope, means the force pulling the rope. Again a highly dynamic view on the topic as modeled! But out of the acceleration given in the equation for the force the model will take into account the mechanical stress or load on the elements of the pulley the acceleration. So as we all know from practical experience a sudden pull has a big effect not only on the friction, but also on the mechanical stress of the elements impacted!


I hope I have been able to present that even just fast and probably not well thought off statements help to make myself aware of aspects of great importance!


Ok, lets go in a new contribution to introduce to you the 3 pillars of my modeling effort!
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Re: Carina sailboat - my scratch build!
« Reply #24 on: April 16, 2015, 09:51:36 PM »

Hello Helmut,

I have been sailing large model yachts for over 27 years.
Have never Bought a Kit, all my yachts have been self built.

Build your yacht, completely, all the Rigging, Mast, Sails, everything.
Make sure to make the Deck so all the Electronics will be able to be fitted later.
Fit the Radio control system - - RUDDER ONLY, NOTHING ELSE !!!!!.

Fit the yacht with adjustable lines to the Sails.
SAIL THE BOAT !!, learn how to Trim the sails.
Learn what Wind the boat will sail in !.
Do ANY corrections to the boat to make it sail correctly.

ONLY WHEN you have done ALL this !!--- fit the ELECTRONICS !!.
Doing this, you will know that IF the boat is not performing as you require, you will know what to alter !!

IF you do not do this, OR, VERY similar, you will spend a LONG time wasting valuable Time.
7 years ago, I too had a Heart Attack, I did all the correct things, and I am now fit and well.

TIME IS PRICELESS

John
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