Section 154.470 - General(a) A cargo tank must have a support system that:(1) prevents movement of the cargo tank under the static and dynamic loads in § 154.406 ; and(2) allows the cargo tank to contract and expand from temperature variation and hull deflection without exceeding the design stress of the cargo tank and the hull.(b) The cargo tank support system must have a key that prevents rotation of the cargo tank.(c) An independent tank must have supports with an antifloatation system that withstands the upward force of the tank without causing plastic deformation that endangers the hull structure when the tank is:(2) In a hold space flooded to the summer load draft of the vessel.CGD 74-289, 44 FR 26009, May 3, 1979, as amended by USCG-2014-0688, 79 FR 58285 , Sept. 29, 2014