Putting in a Quarter Berth

[PQDC]

Hi All,

I've recently bought a 26 foot steel John Pugh and I need to make some changes internally so the 11 year old and 8 year old have somewhere to sleep. I know the interior is a bit of a dog's breakfast, but I want to gradually fix it up over time. Initially I'll need to get a bed for the 4 of us. The wife and I will take the VBerth which doesn't need too much fixing. For the kids I'm thinking of adding a Quarter Berth, and pulling out the current 2 seats and table on the starboard side to replace it with a bench seat / bed with storage underneath.

I've attached some photos. Just wondering what the best approach would be. Do I use 12mm marine ply to make the supporting areas and 6mm or 9mm for the top/lid of the berths? Can I make some of the supports with structural pine, or will this not work in the moist environment of a boat?
I've put several walls in our previously very open plan house, so I'm okay on the tools, but I've not worked on boats before.

Any help or pointing me in the right direction would be appreciated.

Cheers
Peter

[David M]

Roll on a few coats of epoxy so the wood has a minimum amount of water absorption.

[PQDC]

Thanks David.

Cheers
Peter

[boden36]

Whatever you decide on, be really careful to add the smallest amount of weight possible. I am in the process of pulling out an overweight fitout in our boat.
Regards,
Richard.

[roverhi]

You do t need to use marine ply. Exterior grade ply uses the same glue. Marine ply has a core without voids but for your use it's over kill. 12mm would be fine for the deck of the berth though you might be able to go with 10 mm with a few extra supports.

[DefinitelyMe]

Originally Posted by boden36

Whatever you decide on, be really careful to add the smallest amount of weight possible. I am in the process of pulling out an overweight fitout in our boat.
Regards,
Richard.

Maybe not such an issue with a steel boat?

[AndyEss]

I think the exterior ply belowdecks will be fine, and would go with the 12 mm for the berth "deck". Kids have a tendency to grow - and adults may also use the quarterberth at times.
Seal up the end grain as much as possible, varnish might do. A possible problem with attempting to "over seal" with a coating as impervious as epoxy is that if you don't get it perfectly sealed, once moisture gets into the wood, it's difficult for it to get out - which exacerbates rot issues. Having wood "breath" so it can lose moisture is probably the best one is going to do home built.
Counter tops or places where it's likely you will be continually spilling liquids are a different story. A coat(s) of epoxy would do wonders in that situation.
I'm also not sure why weight on a steel boat would be that much of an issue - with an 4 and 8 y.o. (and a steel boat) I'd guess you aren't going to be doing a whole lot of high end racing.

[Free2GoodHome]

I would love to see how this project unfolds as one day I hope to have my own project boat.

[TeddyDiver]

Originally Posted by DefinitelyMe

Maybe not such an issue with a steel boat?

In a 26' boat it sure is, the boat material being irrelevant in this regard..
6mm ply with a couple of stringers and frames in right places would be plenty enough.

BR Teddy

[PQDC]

Thanks for the advice everyone. I'm unlikely to add value to the future selling price on this boat so I'm keen to keep the costs. The structural ply is half the price of marine ply, and easier to find in larger sheets, so I'll go with that for the berths where possible.
Cheers
Peter

[boden36]

Yes, weight is a real issue with a steel boat, especially a small one. Steel does not usually break even weight wise under about 36 ft as the material thicknesses necessary for corrosion resistance and welding distortion control have to be much heavier than would be theoretically desirable from a structural viewpoint.
Because of this many steel boats of less than 30 feet or so really struggle and you have to be careful about burdening them with heavier fit out than necessary.

Regards,
Richard.