The Merchant Shipping (High Speed Craft) Regulations 2022

Risk assessment with reference to wash

11.—(1) A risk assessment with respect to wash must be prepared in relation to a high speed craft before it proceeds or attempts to proceed to sea or on any voyage.

(2) The risk assessment required by paragraph (1) must—

(a) be carried out in accordance with generally recognised procedures for risk assessment;

(b) identify—

(i) any likely areas of potentially hazardous wash, taking into account possible operating conditions and the classification of wash as sub-critical, critical or super-critical, and

(ii) the operating restrictions necessary to reduce that potentially hazardous wash, and

(c) be documented in the route operational manual required by paragraph 18.2.2 of the High-Speed Craft Code, 1994 or paragraph 18.2.2 of the High-Speed Craft Code, 2000.

(3) In this regulation—

“wash” means the sweep of waves left behind by a moving craft, classified as sub-critical, critical or supercritical in terms of the depth Froude number Fnh = Vs/√(gh) where Fnh describes the ratio of the vessel’s speed to the wave propagation velocity in shallow water, Vs is the ship speed in metres per second, g is the acceleration due to gravity and h is the water depth in metres: for the purposes of classification “sub-critical” means Fnh<0.85, “critical” means Fnh = 0.85 to 1.15 and “supercritical” means Fnh>1.15.