Section 19(3)(h) in The West Bengal Maritime Board Act, 2000
(h)vessels, tugs, boats, barges, launches, and lighters for the use within, or without, the limits of a port, whether in territorial waters or otherwise, for the purposes of towing or rendering assistance to any vessel, whether entering or leaving a port or bound elsewhere, saving or protecting life or property, and landing, shipping or transshipping passengers or goods;