Positive Flotation

Positive flotation is very important safety feature. If the boat is destroyed or flooded, positive flotation will give you time to abandon the boat in an orderly manner, take with you everything you need, and also gives you the option to try to remain with the boat (for that you need an immersion suit). In fact, the boat should be abandonned only when there is an imminent danger for it to sink.

In bigger boats it is very difficult to achieve positive flotation, but on Catalina 22 it was relatively easy. I estimated that the bare hull would have a negative flotation of about 50 - 70 kg. (I estimated the volumes of fiberglass and of wood, which is also quite considerable in the hull and especially in the deck, multiplied these numbers by the aprox. density and came with this result). To that, about 300 kg were added due to keel, mast, engine, and rigging weight. So the net result was 370 kg. Plus I added almost 90 kg of lead. The total was thus around 460 kilograms. So to have some useful flotation, I decided that I had to put in about 1200 liters of flotation material, giving me a net of 700 kilograms of positive flotation.

The main source for the flotation was through empty plastic bottles and some 10 liter plastic cans (filled with styrofoam) with sprayed polyurethane foam inbetween.

I used about 20 750 ml polyurethane spray bottles. Theoretically it says that each can give you 40 liters of foam, but in practice, I think it is closer to 20 liters. Several people mentioned that foam can absorb water, but I did not experience this problem, although several times the boat was full of water. Since we have a warm, dry climate, it seems that it dries out during the time the boat is on land.

I tried to distribute evenly the flotation material. There are many small spaces which are not used for anything and which are ideal for filling them with foam. Obviously, if you have to fill in more than 1 m3 of material, some space will inevitably be lost, but I did not feel that it reduced significantly the available storage volume.

Also I made a couple of Styrofoam packs wrapped in plastic sheets to protect it from humidity and potential gasoline contact. One of these packs, 80 liters, was put under the cockpit, the other, with a volume of about 60 liters went into the rear part of the rear bunk space. Finally, it may sound ridiculous, but I even added spaghetti swimming aids (foam type) which I put in all smaller spaces. That gave another 80 liters.