Safe Loading — Subpart C

Determination of the Static Float-Plane

To determine the static float-plane we must understand its purpose in the regulation. The maximum weight capacity we are searching for is based on the gross displaced volume of the boat to the point where down-flooding will sink the vessel. This point of down-flooding is a matter of interpretation of point of leakage. Is it minor or major? Since the Coast Guard must test boats already on the market, this interpretation is part of the testing procedures.

For the purpose of this Guideline, when determining the static float-plane, the user must consider the following features to be sealed:

1. All scuppers or freeing ports, with or without flaps or back-flow devices and regardless of size;
2. Drain holes in the bow;
3. Bait, fish and anchor-well fill/drain holes;
4. Holes in the engine well with boots, in addition to the 3-inch hole already allowed by the regulations;
5. The hull-to-deck joint;
6. Hull doors if able to be closed.

NOTE:
Some transom openings, drain holes or scuppers that may flood the boat during operation must be reviewed by the Coast Guard, and may be considered major down-flooding or water-ingress points. When in doubt about what may or may not be allowed, always consult the Coast Guard.

The static float-plane may be established, following its definition, by either of two methods:

1. Starting on the most forward point of the boat below which the maximum displacement exists. This may be above the deck-to-hull joint, on deck, or established on the deck-to-hull joint if the displacement is to ignore the superstructure. The plane intersects the upper boundary of the stern at or below the points of down-flooding (See Figure 1 in section 2).
2. In some instances, and to maximize the capacity or maximum displacement, the static float-plane may be established as follows:

A line in contact with the lowest point of the sheer that intersects the stem and stern below the intersection of the sheer and the stem at the bow and the intersection of the sheer and the transom at the stern. This line must be located so that the distance between this line and those two intersection points is the same. (See Figure 1.1 in section 2). In both cases, the plane shall be below the lowest point of downflooding.

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