(2) The term "employment" shall not include:
(a) Services performed as an officer or member of the crew of a vessel not an American vessel; or
(b) Services performed by an individual not a United States citizen on or in connection with an American vessel under a contract of service which is not entered into within the United States and during the performance of which the vessel does not touch a port of the United States.
(3) "American vessel" means any vessel documented or numbered under the law of the United States and includes any vessel which is neither documented nor numbered under the laws of the United States nor documented under the laws of any foreign country if its crew is employed solely by one or more citizens or residents of the United States or corporations organized under the laws of the United States or of any state. [1961 c.349 §2; 1971 c.463 §8]