Ventilation

General

Alcohol extended gasoline (gasohol) and other such gasoline based fuels are included in the defined term fuel.

Diesel fuel and compressed gaseous fuels (LPG, CNG, etc.) are not included.

A compartment is any space in a boat that has length, width and height. It may be completely enclosed, partially enclosed or have one of its surfaces completely open. An example would be a compartment under a bow deck or a motor well where there is not an enclosing bulkhead. A canvas cover is considered the same as an enclosing bulkhead when in place.

Open areas are openings that are not specified. Open areas may be at the bottom, side or top of a compartment as long as:

• the open area equals 15 square inches for each cubic foot of net compartment volume (See Figure 2), and
• the opening is directly exposed to the atmosphere.

NOTE:
A number of openings may be added together in order to obtain the required total.
Openings into an open cockpit are acceptable.

FIGURE 2 - Open Area

NET COMPARTMENT VOLUME

Net compartment volume is the result of subtracting the volume of installed items of equipment and accessories from the total compartment volume.
Examples of items that may be subtracted include:

• Engines
• Tanks: Fuel, Water, etc.
• Auxiliary Generators
• Batteries
• Accessory equipment such as refrigeration machinery, pressure fresh water systems, etc.
• For outboard boats -one portable 6 gallon fuel tank, provided there is a defined storage location; i.e. straps or perimeters.

Examples of items that are not subtracted include:

• Stowed Fenders
• Stowed Anchors and Line
• Stowed Chairs
• Picnic Coolers
• Other items that may or may not be in a compartment at any given time.

To assist in determining the amount of cubic feet to subtract, refer to Table I for suggested volumes of engines and batteries, and to Figure 3 for a graph of tank capacity vs. tank volume, in cubic feet.

TABLE I - Typical Volumes of Engines and Batteries

FIGURE 3 - Tank Volume

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