Replacing plywood seating modules on mid-80's cruisers

[tobnpr]

I recently purchased an '85 390EC. The prior owner had recently re-done the interior, but the cockpit cosmetics need work.
Prior research had already made me aware of the problems with the plywood cockpit seating on these models before I even saw the boat, so I wasn't surprised and the boat was priced accordingly; now that the weather's cooling off a bit I'm getting ready to attack the problem.

I REALLY like all the storage available, but the design makes it difficult to get the port/stbd engine hatches up. I'm thinking of re-designing them without the aft seating or perhaps with some kind of fold-down aft seating so that removal of the hatches and access to the CATS-which is tight already- is improved. I'm also deliberating over the materials to use. Obviously plywood (again) is not an option, but I have thought about building them of pressure-treated plywood and having a shop mica them just like the originals- if I build them out of PT at least they can't rot again.

Other options I'm considering include SeaBoard; not just for the seating modules but also the cockpit side panels. Structural coreboard (like Klegecell) is also an option I guess, it would save a lot of weight, but then I'm getting into fiberglass work, painting, etc.

I'm hoping someone here has tackled this already- any comments/suggestions?

 

[Sea Ray 300]

Starboard has its limitations, as it cannot be glued without buying a very expensive glue, made especially for it. :smt009
I'd stick to marine grade plywood, which would be structurally stronger, and more easily worked or glued. :thumbsup:

 

[fwebster]

Been there....done that........and got the $4000 shirt!

Our boat was an '88 390EC and the seats are different so adjust accordingly. Sea Ray used a decent grade of bound plywood for the seat bases but only used silicone in spots to seal the edges. When the first canvas top failed and began leaking any water that got on the seats ran under the teak trim and wicked into the edge of the plywood.

We looked at several approaches and ended up with mahogany plywood and bound all the edges with teak. The plywood was cut to shape, then the teak edges cut and attached. The plwood surface and edges were sealed with West Systems epoxy and the teak was glued on with West Systems then screwed.....the screw holes were filled with epoxy and teak plugs p ut in. The individual panels were then sanded and recoated with West Systems epoxy. THe panels were then assembled with epoxy and screws and dry fitted to the boat. The assembly screw holes were plugged....epoxy and plugs, then the seat bases were finish sanded and coated a final time with epoxy. The final finish is Awlgrip over Algrip primer tinted to Artic white to match the hull. Your boat has a sand color.

We loved the storage under the seats and did not change the design mu ch. We put the icemaker behing a closed door with a drip edge to kepp it out of the weather and we enclosed the drawers under the helm seat in a closed cabinet and made new drawers using teak for the drawer fronts. The teak rope locker door was retained in front of the port seat.

Below is one photo I scanned but it had to be reduced to fit here. If you will send me an email address via PM, I'll scan the other views of the seats and send them to you.

Forget Starboard....way to heavy, although it works very nicely with conventional wood working tools. No mistakes with starboard since you cannot repair it, and at several hundred $ per sheet it would be very expensive.

Forget pressure treated plywood. I don't find it to be dimenionally stable enough for a project like this. It is wet with preservative and must be dry to be stable and hold a finish.

One other point on the engine hatches.......you will find that there is a trick to removing them.....lift the aft end, tilt up one side and rock the hatch to get it up on the aluminum track then slide it back to remove it. You seats have likely sagged some making this harder than needed. I did add a little clearance when we remade the seatbases for our boat and you can probablty see that in the photo. I also never removed the side hatches unless there was a real problem.....all the service can be done from the center hatch if you don't mind getting in there with the engines.

It is a fun project..........enjoy it and the finished product when you all done.

 

[charlieft]

Starboard has its limitations, as it cannot be glued without buying a very expensive glue, made especially for it. :smt009
I'd stick to marine grade plywood, which would be structurally stronger, and more easily worked or glued. :thumbsup:

I agree... marine plywood is the way to go. I replaced the deck on an 85 Larson a few years ago. There were some rotten spots, but I was surprised at how well the marine plywood had held up for ~20 years. I treated the new marine plywood myself with penetrating epoxy.

-Charlie