26.—(1) Parts II and III do not apply to employment where under his contract the person employed ordinarily works outside Northern Ireland.
(2) For the purposes of paragraph (1) a person employed to work on board a ship registered in the United Kingdom (not being a ship registered at a port outside Northern Ireland) shall, unless—
(a)the employment is wholly outside Northern Ireland, or
(b)he is not ordinarily resident in Northern Ireland, be regarded as a person who under his contract ordinarily works in Northern Ireland.
(3) parts II and III do not, however, apply to a person employed under a crew agreement within the meaning of the Merchant Shipping Act[1970 c. 36] 1970.