Teak cockpit replacement

[Bob L]

My new boat (35' Young Sun cutter) is a forest of teak. One area that will need to be addressed quickly is the cockpit. The cockpit seats are teak, screwed into plywood, layed over fiberglass. Several problems: 1) wet teak equals wet butt, 2) locker lids swelled, ill fitting, and heavy, 3) cockpit is like strainer with water dripping below, 4) intend to replace starboard lid with solid material and convert sail locker to quarterberth.



I'd like to rip it all out and install glass with low profile treadmaster (decks will get aggressive pattern treadmaster at some point). Suggestions? Marine ply with glass on both sides, or bottom painted and glass on top? Does it need to be merrati (sp?) or a lower cost ply? Or some sort of starboard material? Or foam with glass on both sides? Is it preferable to have heavy lids or light lids?

Thoughts? Suggestions?

[Tim]

I would not recommend ever using inferior plywood on board, and most definitely not in an area like your cockpit. If you use plywood, choose a multi-ply, void-free product like meranti or okoume, both of which meet the same standard.

That said, I don't think that any plywood is necessarily the right choice for your application. For the cockpit locker than you intend to "deck over", I'd suggest that you build a simple mold beneath the opening and lay up a new cored laminate in the opening. To tie your new material in with the adjacent areas, you'll need to create an appropriate taper on all edges--usually 12:1. (If the top laminate is 1/4" thick, this means you need to start tapering 3" from the opening, for example.)

You could easily create a new sandwich structure in this way. On top of your mold, working from above, laminate an inner skin (later, when the mold is removed, you might laminate additional material over the entire area from beneath, just to help tie it in there as well). Then install core material--something like corecell, or balsa, or Nida-Core, or other such material. I would avoid plywood as a core material. (Yes, I know I used it, but I've explained those circumstances numerous times and despite its success to date, I would not take that road again.) With the new core in place, then laminate overlapping layers of material over the top, and into your tapered area as needed.

As far as the lid goes on the other side, I think there needs to be a balance between "heavy" and "light". The existing lids of fiberglass, plywood, and teak sound unbearably heavy, so obviously there is one extreme. On the other extreme, one could build a very lightweight lid that would never have the proper tactile feel, and would create its own problems even if it were strong, despite being light. What happens if you dissect the existing lid? If you remove the plywood and teak, do you still have a structurally sound lid remaining? It's probably solid fiberglass, or possibly cored construction. Just removing all that wood from the top should lighten it up significantely.

If it's solid glass, but seems flimsy, you could grind the paint or gelcoat off the bottom and add stiffeners or a full core, either of which you could then cover with fiberglass. If the lid is already a cored construction, you probably don't need to do anything else to it.

Starboard or similar would not be the correct material for any of the issues mentioned here.

If you need to build an entirely new lid, I'd build it using a sandwich construction, with whatever core material you like--balsa, Nida-Core, or one of the foam products. This will provide you with the stiffness required to make a good weight-bearing surface, but will also keep the whole thing relatively lightweight--but too light, either.

There are a lot of issues here, and of course this response is glossing over the myriad details that might or might not arise based on the exact circumstances with which you're faced as you get into this project.

[MikeD]

All that teak sure is purty though...

[Bob L]

Good advice Tim. Maybe I will do the cockpit decks with a foam core, like you've suggested, then do the lid out of something else -plywood or solid sheet FRP from McMaster-Carr. I really don't know what the fiberglass looks like underneath the deck. In the quarterberth area the PO glued some sort of foam for insulation and then smeared it with bondo. That's going to come out. The lids look like teak on top of plywood, then with glass applied directly to the underside. It isn't a molded seat/lid that would look OK by itself.