U.S. v. Carroll Towing Co., 159 F.2d 169, 174 (2nd Circuit 1947). For another case involving tugboats, see The T.J. Hooper, 60 F.2d 737, (2d. Cir. 1932) where Judge Learned Hand applies the economic definition of negligence to determine if tugboats must carry radio receiving sets to warn of impending storms.