Title 46—Shipping--Volume 1
PART 178—INTACT STABILITY AND SEAWORTHINESS
§ 178.115   Applicability to existing vessels.
Except where specifically stated otherwise, an existing vessel must comply with the intact stability and seaworthiness regulations which were applicable to the vessel on March 10, 1996, or, as an alternative, the vessel may comply with the regulations in this part.
§ 178.210   Stability information.
(a) Stability information (stability details indicated on the Certificate of Inspection, a stability letter, or a stability booklet), is required on certain vessels by paragraphs (b), (c), or (d) of this section. Enough stability information, including stability calculations and assumptions made to use them, must be provided to allow the master to be able to determine operating guidelines, loading restrictions, and ensure compliance with the applicable intact and damage stability regulations of this chapter.
(b) A vessel which, under § 178.310 of this part, complies with requirements in subchapter S of this chapter, must have stability details on the vessel's Certificate of Inspection, a stability letter issued by the cognizant Officer in Charge, Marine Inspection (OCMI) or the Commanding Officer, Marine Safety Center, or an approved stability booklet. The form in which the stability information must be contained ( i.e. , stability details on the Certificate of Inspection, a stability letter, or a stability booklet) will be determined by the Commanding Officer, Marine Safety Center.
(c) When necessary for safe operation, the cognizant OCMI may place specific stability restrictions in a stability letter or on the Certificate of Inspection of a vessel not more than 65 feet (19.8 meters) in length, which, under § 178.310 of this part, complies with the requirements of § 178.320 of this part.
(d) Each pontoon vessel must have a stability letter and each stability letter issued after March 14, 2011 must be issued by the Commanding Officer, Marine Safety Center.
§ 178.215   Weight of passengers and crew.
(a) This section applies to each vessel, regardless of when constructed, for which stability information is based on the results of a simplified stability proof test.
(b) Except as provided in paragraph (c) of this section, and if not provided in the stability information required, the owner of each vessel must provide the master with the total test weight used in the simplified stability proof test and the number of passengers and crew included in the total test weight. Owners and masters must use a total weight of passengers and crew carried that is based upon an assumed weight per person, which is determined in accordance with § 170.090 of this chapter.
(c) The information specified in paragraph (b) of this section need not be provided if the owner attests that the vessel complies with applicable intact stability requirements when carrying the number of passengers and crew permitted by the Certificate of Inspection with an assumed weight per person determined in accordance with § 170.090 of this chapter.
§ 178.220   Stability booklet.
When the Commanding Officer, Marine Safety Center determines, in accordance with § 178.210(b), that a vessel must have a stability booklet, the owner or operator must prepare the booklet in accordance with subchapter S of this chapter, and submit it to the Commanding Officer, Marine Safety Center.
§ 178.230   Stability letter or Certificate of Inspection stability details.
(a) When the cognizant OCMI or the Commanding Officer, Marine Safety Center determines, in accordance with § 178.210, that a vessel must have stability details indicated on its Certificate of Inspection or a stability letter, the owner or operator must submit the information listed in paragraph (b) of this section:
(1) If § 178.210(c) is applicable, to the OCMI for approval; or
(2) If § 178.210(b) is applicable, to the Commanding Officer, Marine Safety Center for approval.
(b) If § 178.210(b) of this part applies, the applicable information described in subpart C of part 170 of this title, and the calculations used to determine that information, must be submitted in addition to the applicable information listed in paragraph (b) of this section.
(1) Allowable weight and number of passengers and crew on each deck;
(2) Deepest waterline drafts or freeboard;
(3) Location of watertight bulkheads and openings in watertight bulkheads;
(4) Explanation of the vessel's subdivision and specific identification of the vessel's subdivision bulkheads;
(5) Location of openings through watertight bulkheads, such as watertight doors, which must be closed to limit flooding in an emergency;
(6) Location, type and amount of fixed ballast;
(7) Location and details of foam flotation material; and
(8) Maximum weight of portable equipment permitted on the vessel including diving equipment.
(c) If § 178.210(c) of this part applies, the allowable weight and number of passengers and crew on each deck, and the necessary calculations used to determine that information, must be submitted in accordance with paragraph (a) of this section.
§ 178.310   Intact stability requirements—general.
(a) Except as provided in paragraph (c) of this section, each vessel must, in each condition of loading and operation, comply with the applicable requirements of—
(1) Part 170 of this chapter, except subparts G and H; and
(2) Part 171 of this chapter, subparts A and B.
(b) Sailing vessels must meet the appropriate requirements of § 171.055 or § 171.057 in subchapter S in this chapter while under sail, as well as the requirements of § 170.170 in subchapter S in this chapter while under bare poles (if an auxiliary sailing vessel as defined in § 170.055(a) of this chapter) and with storm sails set and trimmed flat (if a sailing vessel as defined in § 170.055(n) of this chapter).
(c) As an alternative to meeting the requirements of paragraphs (a) and (b) of this section, a vessel may demonstrate compliance with an appropriate standard set forth in either § 178.320 of this part for non-sailing vessels or § 178.325 of this part for monohull sailing vessels if all of the following criteria are satisfied:
(1) The length is not more than 19.8 meters (65 feet) in length;
(2) The vessel does not carry more than 12 passengers on an international voyage;
(3) The vessel either does not have more than one deck above the bulkhead deck or, if without a bulkhead deck, does not have more than one deck above the deck from which freeboard is measured excluding a pilot house; and
(4) The vessel's stability has not been questioned by the cognizant Officer in Charge, Marine Inspection (OCMI).
(d) In lieu of the requirements in paragraphs (a) through (c) of this section, a vessel may meet another stability standard approved by the Commanding Officer, Marine Safety Center.
§ 178.320   Intact stability requirements—non-sailing vessels.
(a) As permitted by § 178.310(c) of this part, the following vessels may undergo the simplified stability proof test detailed in § 178.330 of this part, in the presence of a Coast Guard marine inspector, if they do not have tumblehome at the deck, measured amidships, that exceeds 2 percent of the beam:
(1) Monohull vessels; and
(2) Flush deck catamaran vessels which are not pontoon vessels and carry not more than 49 passengers.
(b) As permitted by § 178.310(c) of this part, a self-propelled pontoon vessel may undergo the pontoon simplified stability proof test detailed in § 178.340 of this part, in the presence of a Coast Guard marine inspector, if it satisfies all of the following requirements:
(1) The vessel carries not more than 49 passengers and does not make international voyages;
(2) The vessel operates on Protected Waters only;
(3) The vessel is constructed with only one deck;
(4) The buoyant hull volume consists of two symmetric, fully enclosed hulls;
(5) The cross section of each hull is circular or of wall-sided construction without tumblehome, and constant for at least 90 percent of the length of the hull;
(6) The hulls contain no machinery or tanks;
(7) The portion of the deck accessible to passengers does not extend beyond—
(i) The outboard edge of the hulls, and
(ii) The forward or the aft end of the hulls;
(8) There is no deck more than 0.15 meters (6 inches) above any point on any of the buoyant hulls;
(9) The distance between the centerlines of the hulls is not less than 1.83 meters (6 feet); and
(10) Each hull has a beam or diameter, as applicable, of not less than 0.61 meters (2 feet).
(c) For a vessel that carries not more than 49 passengers, carries no deck cargo, and is otherwise eligible to undergo the simplified stability proof test detailed in § 178.330 or § 178.340 of this part, the authority issuing the stability letter may—
(1) Dispense with the requirements of the simplified stability proof test in § 178.330 or § 178.340 of this part when the vessel's stability can be adequately assessed by alternate means giving due consideration to each item that impacts a vessel's stability characteristics which include, but are not limited to, the form, arrangement, construction, number of decks, route, and operating restrictions of the vessel; or
(2) Authorize a change in the requirements of the simplified stability proof test in either § 178.330 or § 178.340 of this part, when necessary to adequately assess the vessel's stability.
§ 178.325   Intact stability requirements—monohull sailing vessels.
(a) As permitted by § 178.310(c) of this part, a monohull sailing vessel may demonstrate compliance with paragraphs (b) or (c) of this section if it satisfies all of the following requirements:
(1) It does not operate on exposed waters;
(2) It only operates during the daylight hours;
(3) It is of the usual type, rig, and hull form, excluding vessels without a weathertight deck, such as open boats;
(4) It carries not more than 49 passengers;
(5) It is not a sailing school vessel that carries a combined total of six or more sailing school students and instructors;
(6) Its minimum downflooding angle is greater than 60 degrees;
(7) It does not have a cockpit greater than 20 percent of the Length Over Deck; and
(8) If equipped with a cockpit and operating on Partially Protected Waters, the cockpit must be self-bailing.
(b) The vessel may undergo the simplified stability proof test detailed in § 178.330 of this part, in the presence of a Coast Guard marine inspector, if it does not have tumblehome at the deck, measured amidships, that exceeds 2 percent of the beam.
(c) The cognizant Officer in Charge, Marine Inspection (OCMI) may perform operational tests to determine whether the vessel has adequate stability and satisfactory handling characteristics under sail for protected waters or partially protected waters.
(d) The Commanding Officer, Marine Safety Center, may prescribe additional or different stability requirements for a broad, shallow draft vessel with little or no ballast outside the hull.
§ 178.330   Simplified stability proof test (SST).
(a) A vessel must be in the condition specified in this paragraph when a simplified stability proof test is performed.
(1) The construction of the vessel is complete in all respects.
(2) Ballast, if necessary, is in compliance with § 178.510 of this part and is on board and in place.
(3) Each fuel and water tank is approximately three-quarters full. Any sewage tank should be either empty or full.
(4) A weight equal to the total weight of all passengers, crew, and variable loads permitted on the vessel is on board and distributed so as to provide normal operating trim and to simulate the vertical center of gravity, causing the least stable condition that is likely to occur in service. The assumed weight per person of passengers and crew must be representative of the passengers and crew on board the vessel while engaged in the service intended. Unless the cognizant Officer in Charge, Marine Inspection (OCMI) permits or requires the use of other values in writing, weight and vertical center of gravity are to be assumed as follows:
(i) The weight of primary lifesaving equipment should be simulated at its normal location, if not on board at the time of the test.
(ii) The assumed weight per person is determined as provided by § 170.090 of this chapter.
(iii) The weight and associated vertical center of gravity of variable loads must be included as appropriate for the service intended and documented in the stability information required by subpart B of this part.
(iv) The vertical center for the total test weight must be at least 30 inches (760 millimeters) above the deck for seated passengers, and at least 39 inches (1.0 meter) above the deck for standing passengers.
(v) If the vessel carries passengers on diving excursions, the total weight of diving gear must be included in the loaded condition and placed in its stowed position. Not less than 80 pounds (36.3 kilograms) should be assumed for each person for whom diving gear is provided.
(vi) On vessels having one upper deck available to passengers above the main deck, the weight distribution must not be less severe than the following:
(5) All non-return closures on cockpit scuppers or on weather deck drains must be kept open during the test.
(b) A vessel must not exceed the limitations in paragraph (d) of this section, when subjected to the greater of the following heeling moments:
(c) For sailing vessels the heeling moment used for this test must be the greater of the following:
(1) Passenger heeling moment from paragraph (b) of this section.
(2) Wind heeling moment from paragraph (b) of this section.
(3) Wind heeling moment calculated from the wind heeling moment equation in paragraph (b) of this section, where:
(d) A vessel must not exceed the following limits of heel:
(1) On a flush deck vessel, not more than one-half of the freeboard may be immersed.
(2) On a well deck vessel, not more than one-half of the freeboard may be immersed, except that, on a well deck vessel that operates on protected waters and has non-return scuppers or freeing ports, the full freeboard may be immersed if the full freeboard is not more than one-quarter of the distance from the waterline to the gunwale.
(3) On a cockpit vessel, the maximum allowable immersion is calculated from the following equation:
(i) On exposed waters—
(ii) On protected or partially protected waters—
(4) On an open boat, not more than one quarter of the freeboard may be immersed.
(5) On a flush deck sailing vessel, the full freeboard may be immersed.
(6) On a non-sailing flush deck catamaran that is propelled by mechanical means, not more than one-third of the freeboard or one-third of the draft, whichever is less, may be immersed.
(7) In no case may the angle of heel exceed 14 degrees.
(e) The limits of heel must be measured at:
(1) The point of minimum freeboard; or
(2) At a point three-quarters of the vessel's length from the bow if the point of minimum freeboard is aft of this point.
(f) When demonstrating compliance with paragraph (d) of this section, the freeboard must be measured as follows:
(1) For a flush deck or well deck vessel, the freeboard must be measured to the top of the weatherdeck at the side of the vessel; and
(2) For a cockpit vessel or for an open boat, the freeboard must be measured to the top of the gunwale.
(g) A ferry must also be tested in a manner acceptable to the cognizant OCMI to determine whether the trim or heel during loading or unloading will submerge the deck edge. A ferry passes this test if, with the total number of passengers and the maximum vehicle weight permitted on board, the deck edge is not submerged during loading or unloading of the vessel.
§ 178.340   Stability standards for pontoon vessels on protected waters.
(a) A pontoon vessel meeting the applicability requirements of § 178.320 of this part must be in the condition described in § 178.330(a) of this part when the PSST is performed, except that fuel, water and sewage tanks should either be empty or filled to 100 percent capacity, whichever is more conservative.
(b) A pontoon vessel must not exceed the limitations in paragraph (c) of this section when subjected to the greater of the following heeling moments:
(c) With the appropriate heeling moment applied to the most adversely affected side of the vessel, the remaining exposed cross-sectional area of the pontoon must be equal to or greater than both—
(1) The cross-sectional area submerged due to the load shift (for an example, see Figure 178.340(c)(1) of this section); and
(2) One-quarter of the cross-sectional area on one pontoon.
(d) A pontoon vessel must also be tested to determine whether trimming moments will submerge the bow or stern of the buoyant hull. The top of any pontoon must not be submerged at any location, as indicated in Figure 178.340(d) of this section, with the total test weight (W) located on the centerline and positioned as far forward or aft on the deck as practicable, whichever position results in the least freeboard.
§ 178.410   Drainage of flush deck vessels.
(a) Except as provided in paragraph (b) of this section, the weather deck on a flush deck vessel must be watertight and have no obstruction to overboard drainage.
(b) Each flush deck vessel may have solid bulwarks in the forward one-third length of the vessel if:
(1) The bulwarks do not form a well enclosed on all sides; and
(2) The foredeck of the vessel has sufficient sheer to ensure drainage aft.
§ 178.420   Drainage of cockpit vessels.
(a) Except as follows, the cockpit on a cockpit vessel may be watertight:
(1) A cockpit may have companionways if the companionway openings have watertight doors, or weathertight doors and coamings which meet § 179.360 of this subchapter.
(2) A cockpit may have ventilation openings along its inner periphery if the vessel operates only on protected or partially protected waters.
(b) The cockpit deck of a cockpit vessel that operates on exposed or partially protected waters must be at least 255 millimeters (10 inches) above the deepest load waterline unless the vessel complies with:
(1) The intact stability requirements of §§ 170.170, 170.173, 171.050, 171.055, and 171.057 in subchapter S of this chapter;
(2) The Type II subdivision requirements in §§ 171.070, 171.072, and 171.073 in subchapter S of this chapter; and
(3) The damage stability requirements in § 171.080 in subchapter S of this chapter.
(c) The cockpit deck of a cockpit vessel that does not operate on exposed or partially protected waters must be located as high above the deepest load waterline as practicable.
(d) The cockpit must be self-bailing. Scuppers or freeing ports for the cockpit deck of a cockpit vessel must:
(1) Be located to allow rapid clearing of water in all probable conditions of list and trim;
(2) Have a combined drainage area of at least the area required by § 178.450 of this part; and
(3) If the deck is less than 255 millimeters (10 inches) above the deepest load waterline of the vessel, be fitted with non-return devices.
§ 178.430   Drainage of well deck vessels.
(a) The weather deck on a well deck vessel must be watertight.
(b) The area required on a well deck vessel for drainage of well formed by the bulwarks shall be determined by § 178.450.
(c) The freeing ports or scuppers on a well deck vessel must be located to allow rapid clearing of water in all probable conditions of list and trim.
(d) The deck of well deck vessel that operates on exposed or partially protected waters must be at least 255 millimeters (10 inches) above the deepest load waterline unless the vessel complies with:
(1) The intact stability requirements of §§ 170.170, 170.173, 171.050, 171.055, and 171.057 in subchapter S of this chapter;
(2) The Type II subdivision requirements in §§ 171.070, 171.072, and 171.073 in subchapter S of this chapter; and
(3) The damage stability requirements in § 171.080 in subchapter S of this chapter.
§ 178.440   Drainage of open boats.
The deck within the hull of an open boat must drain to the bilge. Overboard drainage of the deck is not permitted.
§ 178.450   Calculation of drainage area for cockpit and well deck vessels.
(a) The drainage area required on a vessel must be computed using the following formula:
(b) Vessels with bulwarks in the forward part of the vessel shall not form a well with the deckhouse which retains water.
§ 178.510   Ballast.
(a) Any solid fixed ballast used to comply with the requirements of parts 170, 171, 178, and 179 of this chapter must be:
(1) Stowed in a manner that prevents shifting of the ballast; and
(2) Installed to the satisfaction of the cognizant OCMI.
(b) Solid fixed ballast may not be located forward of the collision bulkhead unless the installation and arrangement of the ballast and the collision bulkhead minimizes the risk of the ballast penetrating the bulkhead in a collision.
(c) Solid fixed ballast may not be removed from a vessel or relocated unless approved by the cognizant OCMI except that ballast may be temporarily moved for a vessel examination or repair if it is replaced to the satisfaction of the OCMI.
(d) Water ballast, either as an active system or permanent, must be approved by the Commanding Officer, Marine Safety Center.