1710 J. HarrisLexicon Technicum IIPort-nails, are such Nails as are used to fasten the Hinges to the Ports of Ships.
1869 R. W. MeadeTreat. Naval Archit. & Ship-building (ed. 2) 473Port nails, double and single, are similar to clamp nails, and used for fastening iron work.