Basic Flotation

Monohull Boats (not catamarans, trimarans, or pontoon boats): Mono-hull means that if you can draw a continuous line around the hull at the waterline when the boat is at rest it's a monohull. If it makes two or more footprints in the water it's a multi-hull.

With inboard engines (gas, diesel, electric, stern-drive, etc.):

Less than 20 feet (measured on the center line, including rub rails):

This category includes most stern-drive and inboard motor boats.

Requirements:

The boat has to float when swamped, (that is; full of water), with some part of the boat out of the water.

So how do I know how much flotation to put in the boat?

The amount of flotation is based on three factors.

1. The boat weight: that is the weight of the hull, the deck, the seats, etc. Everything not in the next two categories.

2. The machinery weight; engines, batteries, full fuel tank, and controls.

3. The weight of the persons. This comes from the persons weight on the capacity label.

Go to form to calculate flotation.

What do I use for flotation?

Most people use polyurethane foam. Some use polystyrene foam, that is, styrofoam. Others use air chambers. Air chambers that are integral with the hull are not allowed. They must be separate from the hull. Also, you have to pass the test with the two largest chambers punctured. Foam is a good solution, but some don't want foam in their classic wooden boats. In that case they can use balsa, or build air chambers into the boat. The two main reasons boats fail is not enough foam, and not enough foam to support the engines.

How do I know it works?.

Test it!

The best way to find out if your boat passes is to test it. You can do the test yourself, or have a laboratory do it, or the Coast Guard will do it for you. Call the Coast Guard at   1-202-372-1062.

Here's how it's done.

That's It! If you pass all these tests you have done everything the regulations require.

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