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Author Topic: Rigging Question  (Read 2198 times)

Brian60

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Rigging Question
« on: July 18, 2013, 08:31:49 PM »

As I am now reaching the stage of build where I have to start planning out below deck rigging I'd like to ask a question.

My build will be primarily a static model but with the ability to be rc sailed when I fancy doing so. This leads me to ask about rigging. As I have seen in many cases (drum servo) there is a loop of sheet below deck to which is attached a port and startboard sheet that is led up through the decking and thence to the sail/s.  So this acts like a sort of push me pull me to move the sail in either direction.

What I am wanting to achieve is a almost true look. Is it possible to lead just one sheet up through the deck in a central position, then run it through working blocks so that it would operate the sail boom as in real life? Is it practical to do this in a model or won't it respond quick enough with just the initial input from the rudder and then adjusting the sheet 'in/out'.

longshanks

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Re: Rigging Question
« Reply #1 on: July 18, 2013, 10:39:15 PM »

I'm no expert but two problems spring to mind.
Depending on the number of sheaves you could be pulling in / letting out 6x the amount of sheet for normal boom travel.
 
Because of the friction involved the sheet wont run through the blocks on the free side.
Hope this makes sense
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hammer

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Re: Rigging Question
« Reply #2 on: July 18, 2013, 11:02:24 PM »

As on most full size boats let the wind pull the sail out as the sheets are let out. When you wish to tack (turn in to wind) Pull the sheet in to tighten the sail this will increase the speed, on completing the turn set the sail again, as the wind pulls it out. Only one sheet per sail. My sailing trawler works fine this way. The blocks can just be seen in the left side of the photo, they don't work. The bottom block goes out with the top block on the end of the single sheet.
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mrpenguin

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Re: Rigging Question
« Reply #3 on: July 18, 2013, 11:55:50 PM »

@Brian56
Could you provide some more detail of the boat you are working on for this question please? This should help in providing some constructive answers.
An indication of the vessel type (sloop, ketch, square rigger etc), the sail plan and number of masts) and also the approximate size of the vessel will help a lot.
You will likely also need to plan for a (removable) drop keel as well as doing sail control....
A photo would be grand if possible....
 
 
 
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rmaddock

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Re: Rigging Question
« Reply #4 on: July 19, 2013, 10:45:16 AM »

What I am wanting to achieve is a almost true look. Is it possible to lead just one sheet up through the deck in a central position, then run it through working blocks so that it would operate the sail boom as in real life? Is it practical to do this in a model or won't it respond quick enough with just the initial input from the rudder and then adjusting the sheet 'in/out'.

Brian,

Entirely possible, yes.  With enough blocks and fairleads, both under and above the decks, you could do pretty much what you like.  The main consideration is whether you can get enough travel in the sheets.....the problem I've had with my build: have a look HERE.  I wanted to have a scale setup which meant having the mainsheet running to the back end of the boom; that requires a lot of sheet travel. More, if I'm honest, than I've got. I decided to compromise in the end with not getting full boom movement.  The answer would be, as with most models, to attach the sheet further up the boom.

Bear in mind though, that the more blocks and fairleads you employ, the greater the friction will be.

Good luck with your build.

Robert.
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Brian60

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Re: Rigging Question
« Reply #5 on: July 19, 2013, 12:25:13 PM »

Hi  thanks for the answers.

Its a 'Humber sailing trawler' basically the same style as a Brixham trawler but the overal length in real life was around 15ft longer than a Brixham one. I plan on having control over both large sails, the jib sails can take care of themselves as in real life on a traveller and horse.

My idea was to bring out the sheets amidships and aft on the centreline. have blocks attached to a static 'anchor point' on the deck, then run the sheet thru the block and up to the boom where it will be attached to another block. It would appear that the block was working but in essence they are not moving at all, it would be the sheet that was working as in other models.

Does that sound feasible?

Robert I have been following your build with great interest for quite a while now. I have it bookmarked and continually refer to it to see if you have solved problems that crop up for me!

rmaddock

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Re: Rigging Question
« Reply #6 on: July 19, 2013, 02:04:00 PM »

Cheers Brian :-))   A fan, eh?  {-)

My mainsheet is going to come up through the stern deck right next to one of the posts, from there it'll go through a block on the traveller and thence to the boom.  That way, I can put hanked up rope etc on the post to disguise the fairlead.  It'll look like the mainsheet's tied off to the post.  As you've probably seen, the foresail sheets will come up under the wooden deck fairleads, again making them look like real ones tied off.
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mrpenguin

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Re: Rigging Question
« Reply #7 on: July 22, 2013, 07:04:47 AM »

...Its a 'Humber sailing trawler' basically the same style as a Brixham trawler but the overal length in real life was around 15ft longer than a Brixham one.

@Brian56:
So something like this?
http://www.goole-on-the-web.org.uk/main.php?key=675
 
 
I am thinking that you will need to travel a lot of line if you have the sheet on the end of such a long boom. However, I am assuming that the booms do not need to go a long way from centreline in any case, guessing they didn't go too far out on the real boat. You may need separate control of the aft (mizzen?) boom perhaps to aid with turning the boat.
 
 
Here is some video of a Thames barge - the sails are not controlled on this boat at all; only has rudder control.
https://www.youtube.com/watch?v=uuxxt_UcvXo
 
 
The Thames barge (it is not mine  :(( ) has a pretty substantial drop keel, extends about 150mm below the hull and has maybe a couple of kg of lead on the bottom of it. Depending on the scale you are working you may need to plan something similar if going sailing
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Brian60

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Re: Rigging Question
« Reply #8 on: July 22, 2013, 09:16:04 AM »

Yes indeed Mr Penguin.

That plan came from Goole museums, a smallish town about 20 miles upriver of Hull. The image itself is taken from a very resourceful book of the area called Holmes of the Humber. Holmes was a man from the turn of the century from a well to do family, they owned a rather large tannery in Hull. This gave him plenty of time to indulge his hobbies of drawing/painting and his real passion, canoe yawls.

The book is the story of his navigating his various yawls up and down the east coast and inland waterways at the turn of the century. It was after reading the book and seeing the line drawing that I began work on this boat and put my rig supply vessel on the back burner.

hammer

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Re: Rigging Question
« Reply #9 on: July 22, 2013, 04:39:59 PM »

Brian I have sent you a PM, you asked for pictures, here are a few. 1 sailing a round the island, really close, that is control. 2 The deck the blocks on the main sheet only move as a unit, as the control line is fixed to the bottom block. 3 the hatch removed. Red arrows main sheet control. yellow arrow mizzen sheet, only moves half the distance of the main. both operated by winch under forward hatch. Light blue fore sail sheet, dark blue stay sail sheet. Again less movement, by different positions on the sail arm. Green arrow the rudder servos. yes two one normal, the other increases the rudder area by over half. The rudder consist of 2 outer skins of 3mm ply and a centre plate 1/16th steel pulled out so it looks like a scale rudder out of the water.(don't tell). The drum in the centre of the picture lowers and lifts a 1/16th steel plate. (I have found this unnecessary in practice) The ballast consist of lead chips mixed with cement, no external ballast required. The other photo show my west country schooner with furling square sails, again servo operated. Hope you find this useful. Geoff       
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Brian60

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Re: Rigging Question
« Reply #10 on: July 22, 2013, 06:37:34 PM »

Thanks muchly for the pm Geoff. Descriptive text is always a help, but seeing a picture as they say is worth a thousand words! Your photos are now stored for future reference.
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