46 CFR § 153.283 - Valving for cargo piping.
(a) Except as described in this section, a cargo line must have a deck operable, manual stop valve:
(1) In each tank which the line serves; and
(2) At each cargo hose connection point.
(c) The valve required by paragraph (a)(1) of this section may be on the weatherdeck if:
(1) The weatherdeck is the top of the tank;
(2) The line goes through the weatherdeck into the tank; and
(3) The valve is at the point where the line penetrates the weatherdeck.
(d) The valve required by paragraph (a)(1) of this section may be outside the tank if:
(1) The tank is an independent tank; and
(2) The valve is at the point where the line penetrates the tank.
(f) If the cargo exerts a gravity head pressure on a valve required by this section, the valve must be a positive shutoff valve that meets § 56.50-60(d) of this chapter.