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Author Topic: 3 Lifeboat builds, What goes into a model kit.  (Read 321197 times)

nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #100 on: December 29, 2011, 11:31:19 pm »

nah mate......but if you put a little bramble jam and some ASDA special thick cream laced with Couvasier.....they are jolly yummy.....I can vouch for that, and as for the "chocolate cake".....a bit rubbery really, especially the cream on't top.
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Norseman

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #101 on: December 30, 2011, 01:19:29 am »

I can't believe Neil baked rock cakes just to have a one line joke  %%
Now that shows real dedication to his thread  :-))

Probably had no flour so used workshop dust  {-) {-) {-)

Dave
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #102 on: December 30, 2011, 12:12:00 pm »

the one big question is......what are you doing up at half past one in the morning, thinking about cakes.........GET A LIFE MAN!!! {:-{ {:-{ {:-{ {-) {-) {-) {-) {-)
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Netleyned

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #103 on: December 30, 2011, 05:39:49 pm »

He tripped over a sleeper and now can't sleep

Ned
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #104 on: December 30, 2011, 06:48:34 pm »

 {-) {-) {-) {-) {-) {-) {-) {-)

sorry dave........I shouldn't laugh at other peoples downfalls
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RaaArtyGunner

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #105 on: December 30, 2011, 09:32:22 pm »

I can't believe Neil baked rock cakes just to have a one line joke  %%
Now that shows real dedication to his thread  :-))

Probably had no flour so used workshop dust  {-) {-) {-)

Dave
Is this an example of quote between a rock and a hard place  %) %) %)
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Norseman

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #106 on: December 31, 2011, 12:07:10 am »

the one big question is......what are you doing up at half past one in the morning, thinking about cakes.........GET A LIFE MAN!!! {:-{ {:-{ {:-{ {-) {-) {-) {-) {-)


Neil 01:30 feels like 11:30am to me - I am a night worker 99% of the time (that is why I fell over on X'mas daytime - I've only got night vision mate).
So even when I am off work on hols I go to bed about six and get up at ten. Any more sleep than that and I get a headache O0

Dave
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #107 on: December 31, 2011, 12:16:45 am »

a night owl.............. O0 O0.....well, sorry mate..........i'm now just  off to bed, can hardly keep my eyes open, so going to hit the sack....see ya tomorrow with an update...might even get some building done tomorrow instead  of just gassing about it all, lol
neil.
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #108 on: January 01, 2012, 12:49:41 pm »

Well, I suppose I've whinged on enough about how much effort and preparation plus the big expense it takes to get a model kit off the drawing board and into production to put off all of the most hardenned nutters in the game that there are only three more jobs to do  before the kit can be marketed.One is to write the set of instructions, and this is written ( i myself do it in long hand with all measurements taken and step by step process AS I ACTUALLY BUILD IT) and then convert onto the computor with spell check ON, and draw all the diagrammes for construction (free hand at first and then convert onto A3 drawings to begin with.finally reducing size on a photocopier to fit 4 or more to an A4 size sheet, draw the full size working drawings with all fittings corrulated to the list of parts on the instructions page, and finally build the prototype model from all the sums of the parts.

the build time of the model itself is probably a little longer than the average builder will build the kit...say about 600 hours.making sure that all parts fit, another 50 hours to write the instructions, convert them onto the computer( that includes the sectional working drawings of all the parts and another 20 - 30 hours to do draghts of the plans and then final working drawings.
And there you have it.....I haven't totted up the total amount of hours spent on developing a kit, nor what you would be charged if a "professional" on "professional wages" such as  mechanic at your local garage would charge.................I don't want to frighten myself, never mind others who would want to start up in the "game"............I'll let you do that, lol.

But I'll now get down to just building the three prototypes.

As all of the models I have built in the past ( and I do not count the Rother class lifeboat that Dave Metcalf produces, as I had no input into that model what so ever but it is included in this next statement)......... they are all of what we call the "Classic double ender" lifeboat era, from the mid 1920's up until the final Rother was produced in 1982 and all used certain generic parts to their builds, and as such certain fittings from one model can be used on another boat with reasonable scale correctness.

Although certain minor differences might occur they are not too great that  (say for instance) the stanchions on the Rother can be used for the Barnett, and the "A" frames for the tail shafts on the Rother can be used for the Watson class 46' boats, and also used with these brackets, the feet from the little Liverpool class boat can also be used for the Watson on the ends of the Rother A frames.

It makes life a little easier and for all but the very purist in lifeboats( and that is why I try to stick with the classics rather the modern fast afloat boats) if brings the old classic lifeboat into the relms of the model builder who would normally be put off by trying to manufacture those difficult parts like the beltiing and propeller tunnels.

Also as more of these classics are developed, the more the range of fittings are available to build into them, and to be honest, with the final sets that are to go on these three boats, there will be very few fittings now left that aren't available to build the type of boat you desire.

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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #109 on: January 01, 2012, 01:08:58 pm »

So, finally to the build.

First job will be to clean all the moulding marks from the belting and the keel and stem/stern posts ( of which I have omitted to do on the prototypes at the moment.

Next is to fit the running gear of prop shafts,A frames and then rudders.

I found that I only had one set of brackets for the  Watson, and had had to in the past, make up a new set ( as there were no generic ones to fit ) for the Barnett, Mary Stanford....and so I'll just run through the steps to make a set of brackets first. these would also be normally cast in white metal after moulding.

Take a round of brass to make the bearing that will be inserted into the boss of the A bracket, and using a laithe, drill the centre with the diameter of the propeller shaft, ( in this case 4mm) and then shape the bearing in the laithe, putting on a flange at one end, and the outer diameter to ( in this instance) 6mm. set aside.
Take a round of brass for the hub of the bracket boss, and centre drill for the hole to take the bearing, which will be a 6mm hole to take the 6mm outside diameter of the bearing. The bearing will then eventually slide into the boss.

Shape the boss in the laithe to that shown on the set of plans, use carburundum tape to clean up, and then using a parting tool, cut off the boss from the brass round. Repeat this process for the second boss for  it's twin A frame.

Take some length of flat bar ( or if needed shape the bar with a file,/grinder/sander if you want to get the profile of the legs exactly as per boat....but that's for the purist) and jigging up, silver solder the legs to the boss at the correct angle required on the plans. cut the legs to fractionally over length, and set aside for a few minutes.

Take a length of nylon rod about 10mm longer than the length of the boss......this is to go through the boss of the A frame which will go into the rubber mould with the A frame assembled.

Make a rubber mould from two layers of RTV rubber as in the pictures, using lego boxes and plastecine for the process of moulding.

The box is made and a layer of plastecine is put into the box...............the part to be moulded is pressed into the plastecine half way ( this is the process, using RTV rubber for any fitting part) and the round of nylon is moulded in the rubber.Also small impressions are made into the plastecine for locating pins to form in the rubber, in order to stop the mould from sliding later when moulding, ( thus giving an overlapped mould, which would be useless)

Rubber is poured into the exposed half of the fitting and alowed to set, usually overnight.

Once set, the plastecine is removed to expose the unmoulded half and the exposed rubber of the first half is sprayed with a release agent, so thet the two halves of the mould won't stick together. Pour into the seconf half the RTV rubber again to finally cover the master that you have made.

Once cured, remove the rubber from around the master revealing a berfect female mould of your master.

Cut track ways for the metal to flow in, airways for the trapped air to escape, take the nylon out of the master and put back into the rubber mould, put the mould between a sandwich of two pieces of 4- 6 mm ply , hold together with clamps and pour into the access hole your white metal......allow to cool and then remove the moulding from the mould.............remove the nylon rod from the mouylding....and Hey presto...you have an A frame with a hole running through it for the bearing.

The process is shown below for making an A frame in pictures.  the brazing hearth is a constitute material called Vermiculite and obtained from such a place as this... 

 http://www.ebay.co.uk/itm/Soldering-Mat-Pad-Brick-Board-Brazing-Hearth-/120799566544?_trksid=p3284.m263&_trkparms=algo%3DSIC%26its%3DI%26itu%3DUCI%252BIA%252BUA%252BFICS%252BUFI%26otn%3D21%26pmod%3D260898624510%26ps%3D54                   

  and is very cheep for what it is..can be cut with a saw, made into any shape and is just superb for brazing.
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #110 on: January 01, 2012, 01:19:21 pm »

Next step is to insert the running gear into the  tunnels, and this is done in the usual way of making a first drill hole centrally as to where the prop shaft is going to exit the hull, and elongate it using a smaller serated drill bit so that the prop tube will lie true to the A btacket and not "bind" the shaft.

slight alterations have to be made on the A frames used from the Rother class for the Watson..the feet moulded onto the frames are cut off in favour of flange brackets from the liverpool class boat which fit over the legs.

Shown in pictures below.
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CF-FZG

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #111 on: January 01, 2012, 01:22:36 pm »

Neil, I think I got it after the second post, 4 is a bit of overkill :P

Just a thought, have you thought of using 'oilite' for the bearing/bush in the A-frame??


Mark.
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #112 on: January 01, 2012, 01:26:13 pm »

hi matey..  it's this 504 gateway time out  thingy............... sorry . what a pain!!!..... <:( <:( <:( <:(

will delete them and ask the mods to delete the bits not needed.......it's a pain......as for oilite, not heard of that .can you post a link please.

cheers,
neil.
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Netleyned

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #113 on: January 01, 2012, 01:35:32 pm »

Manufacturers name for what you probably know as sintered bushes Neil

Ned
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Smooth seas never made skilful sailors
Up Spirits  Stand fast the Holy Ghost.
http://www.cleethorpesmba.co.uk/

nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #114 on: January 01, 2012, 01:48:27 pm »

cheers, guys.............will have a search for those.
neil..........I used sintered bronze for the first time ever...and didn't know what I was using, ( some one had given me a lump of it years ago.) when it kept ooozing oil, on the master for the ship's bel for the Clyde lifeboat........lovely stuff to work with though, must say.
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CF-FZG

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #115 on: January 01, 2012, 01:54:26 pm »

Oilite is 'oil impregnated sintered bronze' ideal for prop shaft bushings :-))

It's available in stock sizes - e.g. 4mm id 8mm od 10mm long, (flanged or plain), custom, or maybe better for you as bar stock.

TBH, it might be best if you google it, as I've just looked and there are pages of suppliers in the UK and a few of them are requesting 'submit for quotes' type thing.


Mark.
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #116 on: January 01, 2012, 03:06:36 pm »

cheers Mark.......will have a look.

I think I'll look into that for my own boats for the future, but for a kit I feel that the bearings would have to be kept as per kit, the simplest of manufacturing methods. And as the prop shafts are farmed out to an engineering company, for the cheepest way of production they would have to be kept as brass bearings.

neil.
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #117 on: January 01, 2012, 07:03:24 pm »

After the propellor shafts and A frames have been dry fitted the next process is to make the rudders for both types of boats.

Although the rudder for the Mary Stanford is a simpler rudder to make in that it is made from just one piece of 4mm birch faced  ply wood cut to shape as per plan, it has a complicated fixing set as it hinges onto the stern post and is steered by a slide mechanism from a pivot on a hidden servo, and so will attempt that one after the holiday period when the kids have gone back to school and I can spend a couple of hours on it.

However the rudders for the two Watsons are of a normel type with top and bottom rods fixed into the rudder blade and pivotted through both the boat's hull and the rudder skeg.

To make the rudder, I do as I always do,with any boat, make it in three layers of material, in this case a core of 3mm birch faced ply, and an outer skin both sides of 1.8 mm birchfaced ply.

I bend an arm for the steering rod at right angles so that it can't twist inside the rudder, and cut a corresponding slot into the inner centre core to accomodate the rod. A straight cut is made in the bottom of the core piece to take the bottom pivot....and then the three layers are glued together using 2 part epoxy with the two rods sat firmly inside, niether of which will move.

The rudder skegs for the two watsons, although different shapes will also be built in the same way, with either brass or plastic tubing sunk into the bottom of the skeg for the rudder pivot bar to sit into eventually.

see the photos below.
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #118 on: January 03, 2012, 06:47:40 pm »

Today was spent constructing the two different rudder skegs for the Watson lifeboats.

They were both made from a core of 6mm birch faced ply sandwiched between two layers of 1.8mm birch faced ply, and glued together with a waterproof glue. they are also seen with the rudders in place which also were made in the same way of sandwiched timber.

The skegs were drilled with a 4.5mm drill bit to take a sheath of plastic tube which will be the housing in the skeg for the lower rudder rod, and also which will be set into a block of timber inside the boat to support another length of plastic tubing for the upper rudder rod.
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RaaArtyGunner

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #119 on: January 03, 2012, 09:11:02 pm »


Is there any particular reason why the hull keel was not "extended" to eliminate the "wood" block at the end of the rudder skeg as per the other example.
Was pondering these pieces and how they fitted, which is now clearer, and no, I know absolutely nothing about lifeboats, except they are a very popular modelling subject.
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #120 on: January 03, 2012, 10:13:41 pm »

arhhh, now you 've got me there, RaaArty.........Because I'm using the same hull for the two different boats, ( and the two boats were designed on the same hull so no problems there) I have had to extend the grp Keel for the second boat that has the Block of wood as the wooden Keel in order to get the rudder in the correct possition.

Originally I was going to build two boats (they all use the same Watson hull) one with the keel that doesn't have the lump of wood on it, and on the second boat that area that has been cut out was going to have a piece of ply reset into it to re instate the keel all the way back to the stern post, and an external traditional rudder was going to be set onto a rudder bar which hangs onto  the end of the stern post (as in the picture of a barnett I built in part a while ago).

However when I saw the pictures of the second boat I am now building I decided to build that one instead.

This boat, though has an extended keel/rudder skeg that protrudes further out from the stern post for design purposes to protect her when launching down a slip, and because the skeg is set further back, so is the rudder, and this left a gap between the moulded GRP keel and the measurements for the placement of the rudder, and so this has had to be filled with ply.

Once it has been set. it will be faired into the keel with polyester car body filler, and match up to the particular plans of that boat.

so basically just utilising one mould and set of mouldings to make two different arrangements of keels.

hope this explains the discrepancies in the wooden keel skegs.

the pics below are what the second watson was going to be like, rudder arrangement wise, before I changed it for the one you talk about, and as such the keel would have needed extending all the way with timber. As it is, just a little extra is now needed on the rudder keel skeg.

neil.
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #121 on: January 03, 2012, 10:23:40 pm »

Of course all these pieces of timber are now drawn around and put on their relative sheets for future screen printing ( or even possible laser cutting) for the kit.

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furball

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #122 on: January 03, 2012, 10:56:25 pm »

Ahh, the fun of modelling 1930's - 1950's lifeboats....

The RNLI basically asked each station what they wanted on there boats, and so, especially on the Watsons, every damn one was different! Some had internal rudders, some had external rudders. At least two had internal rudders but no deadwood protection around them (like Field Marshal and Mrs Smuts above, but with nothing surrounding the rudder), and then some were built with internal rudders but later converted to external rudders, leaving a large hole in the deadwood (apparently this was because the boats steered somewhat better with external rudders. All the later 46'9" Watsons, the later 52' Barnetts and all the 47' Watsons have external rudders.

One of the documents we've got at Chatham is the parts lists (with diagrams - most useful!) for the steering gear for a lot of the 40's & 50's boats. For those with external rudders it's interesting to note that rudder posts (the square shaft that the rudder slides up and down on) are almost always unique lengths for every single boat - even within the same class! 1/2" shorter here, 3/4" longer there, an each boat was basically hand built. It must have been a nightmare for the RNLI stores to keep track of everything.

Lance

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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #123 on: January 03, 2012, 11:13:29 pm »

That's interesting Lance...something that I didn't know..........but when you think about it, with so many yards building the same class of boat, from natural naterials it is only to be expected really........the total accuracy of one set of builders in one yard would not be the same as in another, and even between boats........so presumably they were all fitted as per what was needed when repaired or built.

It is modellers licence then, that one boat need not be the same as another.....lol............makes the whole job a lot easier to argue your corner against rivet counters, lol
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RaaArtyGunner

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #124 on: January 03, 2012, 11:47:00 pm »

Neil,
Thanks for that, gathered as much, but not knowing about lifeboats, walked where angels feared to tread, but hey us Aussies can handle it.
Thanks again.
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