33 CFR 183.220: Boat preconditioning before flotation tests
Last reviewed: October 14, 2026
This section lists the conditions a boat must meet for at least 18 hours before the tests required by §§ 183.225, 183,230, and 183.235. They cover appurtenances, weights, fuel tanks, swamping and flooding of air chambers.
What it says
A boat must meet the listed conditions for at least 18 hours before the tests required by §§ 183.225, 183,230, and 183.235.
“A boat must meet the following conditions for at least 18 hours before the tests required by §§ 183.225, 183,230, and 183.235:”
Manufacturer supplied permanent appurtenances such as windshields and convertible tops must be installed on the boat.
33 CFR 183.220(a)“Manufacturer supplied permanent appurtenances such as windshields and convertible tops must be installed on the boat.”
The boat must be loaded with weight that, when submerged, equals the sum of the amounts in paragraphs (b)(1) and (b)(2) of this section.
33 CFR 183.220(b)“The boat must be loaded with a quantity of weight that, when submerged, is equal to the sum of the following:”
The weights required by paragraph (b) must be placed so that the center of gravity of each amount is within the shaded area illustrated in Figure 11.
33 CFR 183.220(c)“so that the center of gravity of each amount of weight required by paragraphs (b)(1) and (b)(2) of this section is within the shaded area illustrated in Figure 11.”
Weight must be placed in the normal operating position of the motor and controls and the battery in lieu of this equipment. Columns 4 and 7 of Table 183.75 specify the quantities.
33 CFR 183.220(d)“Weight must be placed in the normal operating position of the motor and controls and the battery in lieu of this equipment.”
Permanent fuel tanks must be filled with fuel, and each external opening into the fuel tank must be sealed.
33 CFR 183.220(e)“Permanent fuel tanks must be filled with fuel and each external opening into the fuel tank must be sealed.”
The boat must be keel down in the water.
33 CFR 183.220(f)“The boat must be keel down in the water.”
The boat must be swamped, and entrapped air in the flooded portion of the boat must be eliminated.
33 CFR 183.220(g)“Entrapped air in the flooded portion of the boat must be eliminated.”
Water must flood the two largest air chambers and all air chambers integral with the hull.
33 CFR 183.220(h)“Water must flood the two largest air chambers and all air chambers integral with the hull.”
Common questions
How long must a boat be preconditioned before flotation tests?
A boat must meet the listed conditions for at least 18 hours before the tests required by §§ 183.225, 183,230, and 183.235.
“A boat must meet the following conditions for at least 18 hours before the tests required by §§ 183.225, 183,230, and 183.235:”
What must be done with the fuel tanks before the test?
Permanent fuel tanks must be filled with fuel. Each external opening into the fuel tank must be sealed.
“Permanent fuel tanks must be filled with fuel and each external opening into the fuel tank must be sealed.”
How must the boat be positioned in the water during preconditioning?
The boat must be keel down in the water.
“The boat must be keel down in the water.”
Which air chambers must be flooded during preconditioning?
Water must flood the two largest air chambers and all air chambers integral with the hull.
“Water must flood the two largest air chambers and all air chambers integral with the hull.”
The text of 33 CFR 183.220
Electronic Code of Federal Regulations (eCFR), current as of March 31, 2026 · Read it on eCFR
Preconditioning for tests
A boat must meet the following conditions for at least 18 hours before the tests required by §§ 183.225, 183,230, and 183.235:
(a) Manufacturer supplied permanent appurtenances such as windshields and convertible tops must be installed on the boat.
(b) The boat must be loaded with a quantity of weight that, when submerged, is equal to the sum of the following:
(1) The sum of 50 percent of the first 550 pounds of the persons capacity marked on the boat and 12 1/2 percent of the remainder of the persons capacity.
(2) Twenty-five percent of the result of the following calculation, but not less than zero: The maximum weight capacity marked on the boat; less the weight shown in Column 9 of Table 183.75 for maximum horsepower marked on the boat; less the persons capacity marked on the boat.
(c) The weights required by paragraph (b) of this section must be placed in the boat so that the center of gravity of each amount of weight required by paragraphs (b)(1) and (b)(2) of this section is within the shaded area illustrated in Figure 11. The location and dimensions of the shaded area are as follows:
(1) The shaded area is centered at the mid-length of the passenger carrying area and at the mid-breadth of the boat;
(2) The length of the shaded area, measured along the centerline of the boat, is equal to 40 percent of the length of the passenger carrying area of the boat; and
(3) The breadth of the shaded area, measured at the midlength of the passenger carrying area, is equal to 40 percent of the breadth of the passenger carrying area of the boat.
(d) Weight must be placed in the normal operating position of the motor and controls and the battery in lieu of this equipment. The required quantity of weight used for this purpose depends upon the maximum rated horsepower of the boat being tested and is specified in Columns 4 and 7 of Table 183.75 for the swamped weight of the motor and controls and for the submerged weight of the battery, respectively.
(e) Permanent fuel tanks must be filled with fuel and each external opening into the fuel tank must be sealed.
(f) The boat must be keel down in the water.
(g) The boat must be swamped, allowing water to flow between the inside and outside of the boat, either over the sides, through a hull opening, or both. Entrapped air in the flooded portion of the boat must be eliminated.
(h) Water must flood the two largest air chambers and all air chambers integral with the hull.
Sections it refers to
The plain-English explanation on this page was written with AI from the regulation text above and checked automatically before publishing: every quote appears in the text, every number comes from it, and a second model confirmed each statement adds nothing the text doesn't say. Regulation text current as of March 31, 2026. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.