Fitting double floor

[Alistair Edwards]

I am planning to have a double floor fitted to my Tigress, and would appreciate some guidance.

My intention is to have a standard height double floor from the thwart back to the transom and a separate low floor forward of the thwart. Hopefully the existing self bailers will work more effectively as any water will collect in the gap between the sections of floor where the self bailers are.

The wooden boat building guide on this website specifies 6mm ply for the floor but I am hoping that in order to minimise weight we can use 4mm ply. If I use additional floor supports (3mm ply) will 4mm ply be adequate?

The Tigress has a lot of rocker so I am hoping that despite only having a low floor in the forward section I will have enough buoyancy under the floors to be able to dispense with the buoyancy bags.

[Marcus]

Alistair, in my boat, N3503, I have a buoyancy arrangement that isn't quite double bottomed, there's a conventional low stern tank that runs athwartships from gunwale to gunwale but extends 900mm forward of the stern. The front tank extends back to the shroud base at centreboard box capping height. This leaves footwells for both the helm and crew formed by the hull skin itself. We've found this arrangement much more comfortable than a double bottomed boat, the boat has 'sit in it' feel rather than a 'sit on it' feel. In addition, the boat can be sailed to windward immediately after a capsize; any water in the footwells drains in seconds through a pair of conventional bailers that are actually a size smaller than those usually found in a conventional boat. I basically copied the arrangement from one of Rob Peebles' boats, 3396. I always thought Rob had some good ideas in this area; he actually wrote a newsletter article explaining these about 15 years ago now. It's a pity really that the class went down the easy route of full double bottoms perhaps we should of adopted the ideas he was promoting to retain the comfort of a single bottomed boat. There are photos of both my boat and 3396 under the appropriate entries on the boat database. If you were to go down this route you could probably get away with either 4mm ply or even 3mm sheet sheathed with some lightweight glass cloth because neither the helm nor crew would be standing on the tanks when moving about the boat.

[darebarry]

Hi Alistair. I have fitted several wood double floors and retro fitted. If you would like to give me a call on 01983 529901 would be happy to have a chat.
Cheers Dare N3521

[Jerry (Guest)]

Marcus, our N3500 went the other way.  Paul T took out part of the double floor to create foot wells.  For us, this was the "geriatric 12" we were looking for.  Ancient joints would have trouble coping with a full double floor.  Although not fully self draining, the volume of water held, even after complete flooding, does not seriously affect performance.  In anything of a breeze the bailers empty the footwell in a couple of minutes or less.  In rough water, a lot gets slopped out over the "afterdeck" through the transom flaps which are set up as "non-return valves (thin perspex from P&B stuck to the transom with a hinge of polythene tunnel repair tape, a uv resistant wide selotape).