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Author Topic: need some building advice  (Read 2189 times)

willie01956

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need some building advice
« on: October 20, 2016, 05:04:03 AM »

just starting a new build, ive built a couple boats in the past that were 30 to 36" long< but this one is going to be 53" long, now with the other ones ive only done single layer of planking for sides and bottom. and then use epoxy and cloth to finish them off,but was wondering with this one should i be doing a double diagonal plank pattern for the build, and then also i thought i would use a vacuum bag system to apply the top layer of planking. i just thought this would make it stronger or am i overthinking the process. thoughts?
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rnli12

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Re: need some building advice
« Reply #1 on: October 20, 2016, 07:07:00 AM »

Hi,
With the size of that hull and generally I would use a double diagonal wishbone planking system, not sure about the vacuum system never used it.
What type of hull or model are you basing it on?
Rich
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Regards,

Rich

Umi_Ryuzuki

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Re: need some building advice
« Reply #2 on: October 20, 2016, 07:43:56 AM »

We single planked two 64" long destroyers single plank over frames and fiberglass.
No problems, however my friend used 3/32" thick balsa planks, and I used 1/16" thick.
I think his hull sanded and faired better, smoother than mine, and he thinks my planking
method, shaving angles and keeping them straight ran a better hull line.

But the single layer and fiberglass are not an issue with either hull.

 :-)

John W E

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Re: need some building advice
« Reply #3 on: October 20, 2016, 01:42:32 PM »

hi ya there

the size of hull which you are intending to build isn't really that big for a single plank - the thing that really governs the thickness/width of planking really is governed by 2 things.  The spacing of your frames and how many there are.   Also, are there any stringers fore and aft between the keel and gunnel and if there are how many?  These are the factors which govern hull thicknesses.   Obviously the more frames you incorporate - the stronger the hull will be.   If you have a look at HMS Exeter build - she is 72 inches long at 1:96 scale.   This is a single planked hull - plank thickness is 1.5 mm - then there is a coating of polyester resin with tissue matt.   Over the top of that there is Plasticard assimilated plating.   No reinforcement of any other kind is used on the hull.

You are discussing diagonal planking - this has its uses, but mainly for keeping hulls extremely light in the build.   It can be a little bit awkward to do depending on the shape of the hull.   If you are building a round bilged hull, you will find that the planks need to be tapered to take into account for the radius of the hull - both fore and aft - from keel to deck.

A better method is, if you have a look how Hatchett did their builds of Bismark and HMS Hood - see how they double planked the hull.  The only thing I personally didn't like about the way this was done - was they butted all the planks on the same frame - rather than staggering the planks like you would do on the brickwork of a house, so that no 2 joints came on the same frame.   I did a build using this method on a hull called the Troyberg where I did the first layer of planking, sanded it smoothly and filled in any indentations and mistakes with car body filler - after that I sanded - then I layed/glued the next layer of planks on top pinning each one with dressmaking pins and brass pins nailed through into the frames.   The dressmaking pins were removed when the glue had dried.    I hope this is of some help I will put some pics on later on in the day. :-)
http://www.modelboatmayhem.co.uk/forum/index.php/topic,33734.0.html
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willie01956

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Re: need some building advice
« Reply #4 on: October 22, 2016, 05:29:28 AM »

thanks for the replies,my frames are going to be 2.65 inches apart and there will be 20 of them,the only stringers i had planed on were at the chine and sheer lines. thats a good idea with the pins to secure the second layer. i wii use that maybe i'll just do 2 layers on the bottom to help hold all the balast that ill need to add.  calculated it at about 65 lbs. Ive been trying to post a pic of the boat, but haven't been able to get to attach, will keep on trying thou.
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John W E

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Re: need some building advice
« Reply #5 on: October 22, 2016, 08:20:24 AM »

 :-)) hi there

by your description it sounds as though you are building a hard chined hull such as an MTB or a cruiser?    If that is the case, I would suggest you add more stringers in to help with the planking - the spacing of your frames are quite close; similar to that of the Exeter.   Unless you wish to double diagonally plank on the chined hull for authenticity, I don't see the need to double plank for strength with the frames that closely spaced.

John
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willie01956

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Re: need some building advice
« Reply #6 on: October 23, 2016, 06:08:07 AM »

ok, thanks for the advise, ill add 1 more stringer to the side and another one on the bottom. you are partially right, the plans had a round bottom on it with no keel , but i altered it to a shallow V ,at 3.5 degrees and i rounded the chine slightly, thought that would give it a little more stability, in the rougher water that ill be running it in. When i get started with the frames, right now I've just cut them out of foam core just so that i can see how will work out before i cut any plywood. ill post a few pics, when i get started assembly.


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