15.—(1) If—
(a)a medical practitioner or medical referee has certified that a seafarer engaged on watchkeeping duties is suffering from health problems which the practitioner considers to be due to the fact that the seafarer performs work during the night, and
(b)it is possible for the seafarer's employer to transfer the seafarer to work—
(i)to which the seafarer is suited, and
(ii)which is to be undertaken during periods such that the seafarer will cease to perform work during the night,
the employer must transfer the seafarer accordingly.
(2) In paragraph (1), “night” means a period—
(a)the duration of which is not less than nine consecutive hours; and
(b)which includes the period between midnight and 5 a.m. (local time).