Keel height

[cordite]

As I'm new at this I have to ask. I am using 7mm ply for the ribs of a Bathurst (Australian) Class mine sweeping corvette I am building.

Two questions - is the 7mm alright for the keel and if so what is the consensus on the height of the keel.

Also I presume you cut out the centres of the ribs for ease of maintenance. Is 15mm OK for the ribs when the centres are cut out

[NorthSea]

Hi Cordite, welcome to the board.

You didn't say what scale you are building or if it is a working model, but I guess it a large scale. Personally I would have like my keel more than 7mm, maybe 12mm? If you cut it from ply, make sure that you cut it so that most of the long grain plys run lengthways. That will help to keep it straight. If you use a thicker keel, you can reduce the height of the keel.

For the thickness of the frames, 15mm sounds OK to me. Your aim should be to keep as much internal space and as little weight in your hull as possible without making the frames too weak. Cut a few and see how it goes, before you do them all, and watch out for weak points that you might create. If it's a static model you don't need the space inthe hull so you don't need to cut them out I thionk. I have no experience with normal ply, I use marine or birch ply and I think that's what you should be using.

As a guide to sizes, have a look at my Pyotr Velikiy build on the forum. The frames are 6mm birch ply, and 20mm broad give or take. The keel is 12mm x 20mm of really straight stripwood from a local DIY store. And a bit of 12mm ply for the bow section.

Hope that helps, you'll get other opinions from other builders. Post your build on the forum and you'll get lots of help.

[HvyCgn9]

Those dimensions sound fine for your project mate any smaller than 15mm on the frames would be a pain to do. Are you redoing your Hull ??

Cheers Bruce

[tweety777]

Height gives much more strength.
What you could do is build the keel up of 2 layers of 7mm thick plywood, and make sure you glue it together on a straight surface, helping to keep it straight with a large amount of weight, then it will not bend anymore.

On my next model I will build all the frames and the keel of 9mm thick plywood (model will be 1,96m long and about 0,35m wide), but I will also add some open tweendecks that do the same thing as the keel, but now horizontally.
The centre of the frames will be cut out.
At the top of the frame i'll cut it out 50mm from the side, then cut vertically down until there is not all too much height anymore.
I don't follow the shape of the frame, I just make sure there is some height at all places, and make it easy to build anything on it and to run wiring through it.
The tweendecks help to keep the frames aligned properly, and off course to reinforce the hull.
This way 9mm should be enough to make it unable to bend the hull in any way, even when the plating still has to be applied.

Greetings Josse