(a) Applicability. This section applies to towing vessels that are not excepted vessels, as defined in §136.110 of this subchapter, and that were built after January 18, 2000. Except for outboard engines or portable bilge or fire pumps, each fuel system must comply with this section.

(b) Portable fuel systems. The vessel must not incorporate or carry portable fuel systems, including portable tanks and related fuel lines and accessories, except when used for outboard engines or portable bilge or fire pumps. The design, construction, and stowage of portable tanks and related fuel lines and accessories must comply with the ABYC H-25 (incorporated by reference, see §136.112 of this subchapter).

(c) Vent pipes for integral fuel tanks. Each integral fuel tank must have a vent that connects to the highest point of the tank, discharges on a weather deck through a bend of 180 degrees, and is fitted with a 30-by-30-mesh corrosion-resistant flame screen. Vents from two or more fuel tanks may combine in a system that discharges on a weather deck. The net cross-sectional area of the vent pipe for the tank must be not less than 312.3 square millimeters (0.484 square inches), for any tank filled by gravity. The cross-sectional area of the vent pipe, or the sum of the vent areas when multiple vents are used, must not be less than that of the fill pipe cross-sectional area for any tank filled by pump pressure.

(d) Fuel piping. Except as permitted in paragraphs (d)(1) through (3) of this section, each fuel line must be seamless and made of steel, annealed copper, nickel-copper, or copper-nickel. Each fuel line must have a wall thickness no less than 0.9 millimeters (0.035 inches) except for the following:

(1) Aluminum piping is acceptable on an aluminum-hull towing vessel if it is at least Schedule 80 in thickness.

(2) Nonmetallic flexible hose is acceptable if it:

(i) Is used in lengths of not more than 0.76 meters (30 inches);

(ii) Is visible and easily accessible;

(iii) Does not penetrate a watertight bulkhead;

(iv) Is fabricated with an inner tube and a cover of synthetic rubber or other suitable material reinforced with wire braid; and

(v) Either:

(A) If designed for use with compression fittings, is fitted with suitable, corrosion-resistant, compression fittings, or fittings compliant with the SAE J1475 Revised JUN96 (incorporated by reference, see §136.112 of this subchapter); or

(B) If designed for use with clamps, is installed with two clamps at each end of the hose. Clamps must not rely on spring tension and must be installed beyond the bead or flare or over the serrations of the mating spud, pipe, or hose fitting.

(3) Nonmetallic flexible hose complying with SAE J1942 Revised APR2007 (incorporated by reference, see §136.112 of this subchapter), is also acceptable.

(e) Alternative standards. A towing vessel of less than 79 feet in length may comply with any of the following standards for fuel systems instead of those of paragraph (d) in this section:

(1) ABYC H-33 (incorporated by reference, see §136.112 of this subchapter);

(2) Chapter 5 of NFPA 302 (incorporated by reference, see §136.112 of this subchapter); or

(3) 33 CFR chapter I, subchapter S (Boating Safety).