33 CFR 168.50 - Performance and operational requirements.
(a) Except as provided in paragraph (c) of § 168.10, at all times during the escort transit each tanker to which this part applies:
(1) Must be accompanied by escort vessels that meet the performance requirements of paragraph (b) of this section (but not less than the number of escorts required by § 168.40).
(2) Must have the escort vessels positioned relative to the tanker such that timely response to a propulsion or steering failure can be effected.
(3) Must not exceed a speed beyond which the escort vessels can reasonably be expected to safely bring the tanker under control within the navigational limits of the waterway, taking into consideration ambient sea and weather conditions, surrounding vessel traffic, hazards, and other factors that may reduce the available sea room.
(b) The escort vessels, acting singly or jointly in any combination as needed, and considering their applied force vectors on the tanker's hull, must be capable of -
(1) Towing the tanker at 4 knots in calm conditions, and holding it in steady position against a 45-knot headwind;
(3) Holding the tanker on a steady course against a 35-degree locked rudder at a speed of 6 knots; and
(4) Turning the tanker 90 degrees, assuming a free-swinging rudder and a speed of 6 knots, within the same distance (advance and transfer) that it could turn itself with a hard-over rudder.