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To fix or not to fix? Bowed center keel


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I bought my Pride of Baltimore on eBay from a modeler who had started the kit. The keel, sternpost, transom fillers and bulkheads were already glued. The rabbet was cut, but it needs quite a bit more work. I removed the keel and sternpost so I can more easily rework the rabbet without damaging the keel. The transom fillers were not good, so I removed them and will make new ones.

Finally, to my question... sighting down the center keel, there's an visible bowing. It's not a whole lot, maybe 1/16" gap when a straightedge is laid along the keel. By flexing the bulkheads  ( H and I) in the bowed area, I found that I can straighten out the bow by separating two of the bulkheads on the concave side of the bow. I fitted but haven't glued a block of scrap 2x4 to make the separation. Problem is, this takes these two bulkheads out of parallel. Is it worth fixing the bow as I've temporarily done? Will the out of wack bulkheads be a problem in fairing and/or planking?  Maybe split the difference and make this block narrower to partially straighten the bow while keeping the bulkheads more parallel?

20200722_102748[1].jpg

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To bad the bulkheads have been glued otherwise you could cut another frame by tracing the existing onto plywood or wood. I would use the scrap filler to fully correct the bowing. Your fairing will be more difficult but you can shim were needed. Is it a double plank model? If so you have two layers to play with which would help. If you are going to use treenails and correct spacing for plank butts a single plank model might be a problem as your butts would be asymmetric however with a double plank this would not be a problem as you are gluing to the first planking and not the bulkheads. I do two plank bulkhead construction but add false frames for my second planking and just glue to the first plank.

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For the rest to be correct, the spine and the moulds should be as straight and square as can be done.

 

Can you determine the type of glue used to bond the moulds to the spine?

If it is PVA, a good soak in 91% isopropyl alcohol should free them.

If it is (the Fates forbid) CA, then  use acetone.

 

Then on a base board, blocks can hold the spine in a straight line, and the moulds can be bonded square.

 

Am I seeing this correctly?  Both edges of the moulds are sanded to a smooth curve?  

I am thinking that the edge closest to the dead flat should be sharp and the outer edge - and all of the char should be down beveled.

 

The scrap 2x4 will make a low cost and effective filler between the moulds, if you have the tools to cut it into slices and scroll cut most of the outside and inside curves before fixing between the moulds.

 

All of the above is theory.  I jumped straight from pre-carved kit hulls to scratch POF,  so I have no actual experience with POB.

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As Jaager already said the spine should be straight and true or you will fight it the whole way during the hull build. Would it be possible to glue another 1/8” piece opposite to each other to the sides of the bulkhead that is off. That would put wood where it is supposed to be for planking, treenails or whatever else might need the edge of the bulkhead to be in the correct place. Seems to me the simplest way and nobody will ever know but us and I won’t tell 😁

 

Tom

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