Help with cabin sole

[D Wrate]

Last night I pulled up the teak and holly cabin sole on our Crown 34 in an effort to stabilize my salon table. What I found was interesting.

The floor under the 1/4" teak is far from flat. The floor in the forward corner under the table rises substantially such that the 1/4" teak is held down to a compound curve by a couple of screws. Not terribly effective in my case. The table is unstable because it is basically only screwed to the 1/4" teak ply. Longer screws will help and I may through-bolt the ones I can reach.

Under most of the floor 3/4" plywood is laminated in the fiberglass. Fore and aft of the "floor beam" that separates the galley floor from the main floor there was just glass and no plywood. Same for the area to port and aft of the mast. In this area a section of the glass was cut out reducing support allowing both sides of the floor to flex independently.

My floor flexes in both of these areas. The teak floor panels are damaged around the edges from the flexing and having to conform to the curved sloping surfaces around the edges of the floor.

My initial plan is to add a bottom layer of 3/8" ply under the 1/4" teak to stiffen the floor where there is no plywood laminate. By tapering the extra layer, the effect of the compound curves could be reduced allowing the teak ply to to conform to the floor. Obviously some extra fitting will be required there but this could still be a workable solution.

Does anyone else have a similiar problem? Any solutions?

Thanks for listening :-)
David

[Tim]

When you say the floor is "far from flat", do you mean that it has a crown, or a concave shape, or that it curves up and follows the curvature of the hull in some areas? The teak isn't well secured either and is coming free in areas where it is forced to follow the curve into the hull, is that right?

I gather the root of your problem is that the sole is inadequately supported and flexes, causing the teak to come free, as well as other issues? Is the flexing limited to those areas without the 3/4" plywood core and where a support was removed at some previous time?

If you can't stiffen the sole from underneath, with floors (transverse supports) or other similar means, then adding structure to the top (such as the plywood as you suggest) would help. Still, you may need to force the sole back into the proper position, if it's sagged in the unsupported areas. You should ensure that any new plywood you install above the existing is well fastened to the underlayment in all areas, which will work to stiffen it.

Additional adhesive or fasteners to pull your teak plywood sole back into position properly would help too. Plywood has trouble with compound curves, depending on their severity. With proper adhesive and clamping pressure, though, you should be able to make the upper layer conform as needed.

Is this sort of what the situation is?

[D Wrate]

The floor is essentially flat except for one area where it curves up to match the hull contour.

The edges of the floor "pan" if you will, are all radiused so if the 1/4" ply panel is brought right out to the edge it ends up raised up off the actual floor. When stepped on repeatedly, eventually the ply gives out and the edges break.

I am thinking that if I can radius the edges of the new plywood to match the radius of the floor pan, I will be able to bring the new plywood right out to the edge and the 1/4" ply will be better supported.

An additional 3/8" in thickness will also help reduce the amount of flexing the 1/4" ply has to do to match the curvature of the floor.

The floor is very stiff every where the 3/4" ply is used. For these areas I fasten the 3/8" ply down with stainless screws into the 3/4". In the areas without the 3/4" ply I think I will through bolt the 3/8" ply using large fender washers underneath and counter sink washers and the bolt heads on the top.

Hopefully this will help stiffen the areas where the floor was cut and where the 3/4" ply was not used.

Scream if you think this is foolish!

Thanks!
David

[Tim]

It sounds like a decent answer to the problem. Without really seeing what you have firsthand, it's hard to say if there's another solution that's any better. Adding material on top is usually the easiest way to reinforce something like this, as other means tend to require removal of the whole thing first.