Home-Port Doctrine Law and Legal Definition

The Home Port Doctrine is a principle of Maritime law resulting from the Foreign Commerce Clause of the U.S. Constitution. The rule mandates that a vessel engaged in interstate and foreign commerce is taxable only at its home port, which is the place where the vessel is registered.

Ocean going vessels, plying international waters, engaged in either interstate or foreign trade, even when owned by residents or citizens of this country, may not be taxed by any jurisdiction other than that of their home port. [Continental Dredging Co. v. County of Los Angeles, 366 F. Supp. 1133, 1135 (C.D. Cal. 1973)]

The home-port rule originally provided that the taxable situs of ocean-going vessels was exclusively within the domicile of the owners thereof and the place of registration. [Hays v. Pacific Mail Steamship Co., 58 U.S. 596, 17 Haw. 596, 15 L. Ed. 254 (1854).] Subsequent decisions have eroded the rule with respect to interstate commerce only, now providing for local taxation on an apportioned basis in many circumstances. For example in Scandinavian Airlines v. County of Los Angeles, 56 Cal. 2d 11, 14 Cal. Rptr 25, at 29-34, 363 P.2d 25 (1961), the Court held that a two-day stopover was insufficient to alter foreign situs. Although the theories supporting the home-port rule have shifted over the years the rule itself with respect to foreign commerce remains intact.