Darren Bos wrote:

You are trying to do several different things, so one strategy probably doesn't work for the whole project.  It's also nice to try and find the solution that is the least expensive and least work.

To make the footwell shallower, to my mind it seems like new steel is the best choice.  This will be the strongest and most trouble free way to deal with a horizontal surface in which wood and steel will not get along. The footwell is likely a simple rectangular shape.  You could make a template from cardboard and cut the steel with thin cutoff disc in a grinder.  It will need a bit of steel angle stock under it to make it stiff, you can probably just copy the underside of the original cockpit sole. 

It sounds like your original thought was to build up the cockpit benches with wood to give them more height so that you could have a deeper lip to the locker in which you could implement the double coamings for the hatch.  I'll wait for pictures and for others to comment, but the effort to build up the benches in a lasting way might be more work than an alternate locker lid.  I once made a set of wood cockpit lids for a Hurley 20.  I used cedar and fiberglass to make lids that had an inset gasket.  It's not as good a solution for ultimate watertightness, but they were very strong.  If you're just coastal sailing this would be quick, cost effective and safe.

Annie's idea of closing the entire cockpit gives the ultimate in watertightness, if it can be made to work in terms of space, access, comfort.  Here again, a sheet of steel makes the most sense for strength, maintenance, cost.  

I took on rebuilding an aluminum boat a few years ago without much metalworking experience before that.  Boaters think a lot about wood and epoxy because they are everywhere, but metalwork is just different, no harder.  I prefer the feel of wood and find it more pleasurable to work with, but for the outside of a boat there are good reasons including strength, durability and maintenance to stick with the metal you already have.

With some pictures, I'm sure others will post even better ideas.

some pictures at last! I hope these will help. Yes, you do understand my original concept for a solution correctly.

I think I may end up simply replacing what is already there and trying to find a way to keep them shut.

I like the idea of decking over the cockpit completely with just a small shallow footwell. However, I think it is well beyond my design and fabrication skills. I guess that the making of new access would either mean trashing the existing interior to get around the engine under the boat deck or cutting new holes in the new deck?  If it was going to involve that much effot and cost I would think seriously about taking the whole coach roof and cockpit out and transplanting a new steel structure over the resultant hole. I would certainly need a lot of help to design, spec and construct such a major project. It appeals because she is 50 this year and it could turn her into a tough voyager for one or two persons and make such travels possible for me. Somerled would also get a whole new lease of life!

Building Branwen's plywood cockpit involved bolting wood to steel. I separated the two materials with Denso tape, the greenish fabric plumber's repair tape impregnated with an unpleasantly sticky substance which seems never to dry out. I don't think there has been any corrosion. On the other hand, dribbles of green goo get squeezed out of the joints.

David Tyler wrote:

Nick, going back to your original posting, I see that you already have a plywood coachroof joined to a steel deck. How was this done? And is it satisfactory? I would imagine that it is going to be similar to the situation that Annie describes on the Wylo II. The only situation that I could imagine as being satisfactory would be with through bolts and a non-setting sealant between wood and steel. Whatever was used originally is not likely to be currently in manufacture, so you'd have to find a modern equivalent. The most likely thing I can find is non-setting butyl rubber sealant.

Whatever you're trying to improve, or add to, I'd think in terms of something like your deck/coachroof joint or the Wylo II hull/ deck joint. That is, a steel flange welded to the boat, to which a ply/epoxy structure is bolted, with such a flexible sealant between them; not a face-to-face bonded joint. 

Can you post some photos of the cockpit area, so that we can see what you're aiming to do

G unfortunately I cannot upload files. There is some issue of communication between my sony android phone and the "choose files" or "browse" buttons on the site. The boat boat was built by parkwood in southampton in 1968. The hull was built in holland and the wooden parts added in uk. I do not know how the coach roof is attached but there do not appear to be any major issues with the joint leaking or corroded. I will try to get some pictures to a laptop and see if I can upload that way. Thank you for your suggestions so far.

Generally speaking, I'd agree with Paul 100%, having lived for several years on a steel boat.  However, it's not invariably the case.  For example, the centre-board version of Wylo II, has a wooden deck.  Several boats have been built to this design without issue, including the original Wylo II, which is still going strong still not a 'rust bucket''. The main reason for this is that there is one, very simple, very straightforward joint between steel and wood, and a lot of care and attention can be paid to this connection.  (Conceivably - and I realise that this is hardly an attractive solution - you could cut out the cockpit area and replace the entire thing with wood.  But I like wood.)

I completely understand why you want to avoid steel cockpit locker lids - they are a terrifying concept, conjuring up images of amputated fingers and toes.  Have you thought about completely sealing the cockpit from above and gaining access to the space from inside the boat?  (I have no idea of how your boat is laid out, Nick, so this could be a completely nonsensical suggestion.)

Darren Bos wrote:

I think Paul is right, this seems like a nightmarish place to mix wood and steel.

If the reason you didn't want to use steel was that you don't have welding equipment, most of the expense comes from the fit-up, not the welding.  If you cut all the steel yourself and have the surfaces cleaned back to bare steel, and the new pieces test fit, then the number of hours you need a welder for the actual welding is usually a manageable cost for a project like this.

dDarren, I do not have the skills or facilities to cut and bend the steel plate myself and I was trying to avoid having steel locker lids. There would be quite a lot of new metal to be welded to the existing openings to increase the height of the lip upstands as well as a second row of coaming to make watertight.  I have not seen any examples in steel that I could crib from.  Ideally, of course, I would remove the entire coach roof and cockpit coamings and have a new steel assembly dropped on and welded in place. Matbe a bit more project and cost than I can manage at the moment. Thanks for your suggestions and it has certainly made me stop and think  about how to proceed. Nick