need to fab new companionway hatch

[nightowle]

Hi All,

my current three piece 'door' setup that closes off the companionway is on life support. It's made of 1/2" plyboard with a veneer cover (maybe teak) and was probably varnished many moons ago by the previous owner. I was at home despot looking at some possible replacements. What do you think of MDF stained and polyurenthaned. Will it hold up for a few seasons?

TIA
Brad
Seattle
'75 ODay 27'

[Guesser]

Yes, it will. I have made them out of this a couple of times and they hold up well. Although I usually try to keep a boom cover over the companionway during the winter (I'm in seattle too). You might also try a couple of the used boating stores, (Fremont and Shilshole), as a lot times they have a piece or two of teak that you can get pretty cheap.

[Freesail99]

I would use plywood that had been epoxied and varnished over MDF. It's going to get wet. You could even use hardwood plywood which would look very nice with the epoxy and varnish finish...

[Quickstep192]

I doubt that MDF will hold up outdoors for more than a couple of months. You might get a little more time by encapsulating it in epoxy, but that would add a lot of expense. Additionally, if it slides into a slot like mine does, it could swell and be difficult to remove or do damage. If you need a quick fix to hold you until you can make something more permanent, exterior plywood would be a better choice. The really cheap stuff is called CDX which has a bad side (grade C) and an awful side (grade D) and is rated for eexterior use (the X). Next choice is BCX which has a pretty good side and a not-so-good side. Put the bad side toward the inside and give the whole thing a couple of good coats of paint (maybe teak color) paying special attention to the edges. Painting will slow the affects of the weather. If you want something a little nicer, get ACX plywood.

[T37Chef]

Woodworking for Watercraft - Hatches and Companionways

If you don't purchase from them...at least you may get some good ideas

Ohhh...

And whatever you do don't go with teak veneer plywood, unless you NEVER plan on sanding it...done that one before trying to save $$$ and it turned out to be a waste of time & money...although it did look good the first year?

[nightowle]

Thanks everyone...good ideas. and thanks Guesser....I was at the second hand store in Shilshole yesterday mostly browsing and bought a book. I never thought of asking them about teak pieces. Maybe next time I head over to the boat in Salmon Bay.
Brad

[sailingdog]

MDF is generally a poor choice of materials to use on a boat, or anywhere near water... You can make a set out of marine plywood that has been epoxied to make it waterproof and help prevent it from delaminating.

Another choice might be to go with ABS to make the new drop boards. if you get a smoked or tinted ABS, you'll be able to get some more light inside the boat, and the stuff doesn't really need to be finished in any way.

It depends on the boat... how traditional a vessel she is and how traditional "looking" you want to keep her.

[PBzeer]

I'll second sailingdog's suggestion. The one thing you do have to watch though is scratching them up. Best if you have some kind of fabric holder with divided pockets to put them in. Also, in making new ones, you can decided how many pieces you want, based on stowing them. So you could have 2 or 4, as well as 3, depending on how big you want the pieces to be.

[Sabre66]

Do not use MDF! It will only hold up as long as the finish does and it has very little strength and wont hold fasteners very well. If you don't want to use Marine Ply, try using MDO (medium density overlay) It's exterior rated plywood with a smooth paper face, sign makers use it for all types of exterior applications and it's available in most lumber yards.
If you need it smooth on both sides you'll have to make sure you ask for it, otherwise it's smooth one side only.
CDX is also a bad choice as it's a framing lumber ment for sub floors and wall sheathing. It's prone to warping and has lots of voids in the layup. Ac is an interior grade Ply and they make it smooth by plugging voids with "foot balls" no matter how much you paint these will always show through the finish.

[yotphix]

Good advice Sabre, the signboard is surprisingly durable and dimensionally stable and will last for years. And lets be clear. MDF has NO place on a boat for any purpose ever!
SD, Is there really such a thing as clear, smoked or tinted ABS? Or did you mean Acrylic, Lexan or Polycarbonate?