Plywood epoxy Catarmaran Bouyancy

[cavalier mk2]

I like empty 1/2 gallon bottles placed in the appropriate areas as they can be removed for inspection/repair and allow air circulation in a wood boat. If you figure out the amount of wood and appropriate density of the same you can crunch the numbers adding in the weight of epoxy/glass/gear/stores and know if you will float or not. Before being waterlogged a pre epoxy wood boat will float higher if no other flotation is used. While epoxy might sink a 6mm piece, 9mm should float coated both sides.

[nickvonw]

thats a pretty good idea with the half gallon bottles..beats foam...for sure

well atleast by the sounds of it with a few stragegically placed watertight compartments most plywood epoxy boats shouldnt sink

maybe the best is just to avoid hitting things in the first place

[oldsailor7]

You have to be careful with 1/2 Gall bottles -- because if you have a big enough hole in the bow compartment, (the most likely event), the small bottles can be very quickly washed out of the boat by wave action. Some method of locating the bottles in the hull is advisable. Some people have used a net for this purpose. Some have used pour in foam to lock in the bottles, but as Richard Woods said that foam absorbs moisture over time.
We used soft plastic acid bottles of something like 50 litres each which could be inflated in place to fill the major spaces in the floats of our trimaran. The same could be done in the flotation compartments of a catamaran. Just a thought.

[cavalier mk2]

Crash bulkheads should be included also but net is the way to go, locking them in solid defeats the purpose of ventilation and access. Being able to adjust trim or remove for assistance righting is also a benefit. They are great in wings for inverted flotation. I like the rectangular juice bottles because there is less wasted space. We also use them for water storage so a tank catastrophe won't ruin the water supply. Easy to pack in a water load when docks and hoses aren't around too. Plus the darn things are free whenever I've finished the juice.....