Section 147.839 - Mad Dog Truss Spar Platform safety zone(a)Description. The Mad Dog Truss Spar system is in the deepwater area of the Gulf of Mexico at Green Canyon 782. The facility is located at 27°11'18.124" N., 90°16'7.363" W. and the area within 500 meters (1640.4 feet) from each point on the facility structure's outer edge is a safety zone.(b)Regulation. No vessel may enter or remain in this safety zone except the following:(2) A vessel under 100 feet in length overall not engaged in towing; or(3) A vessel authorized by the Commander, Eighth Coast Guard District.USCG-2015-0512, 80 FR 54721 , Sept. 11, 2015