After subsection (3) insert—

“(3A)

For the purposes of subsection (3) “sea”—

(a)

includes tidal rivers and estuaries;

(b)

does not include—

(i)

non-tidal rivers and canals where the significant wave height could not be expected to exceed 0.6 metres at any time; and

(ii)

lakes and lochs where the significant wave height could not be expected to exceed 1.2 metres at any time.”