Vlad, thanks for that, it makes sense, John

Safety exits from cargo tank area; the one in the engine room is without the "box". I have seen this arrangement on gas tankers and Prelude FPSO, but not container vessels or oil tankers.

Cheers

Vlad

Does anyone know the purpose of the 4 boxes attached near he waterline? There are indications of an opening in the hull in a position where you might have expected a fifth box to have been fitted. I have noticed this type of box on other ships recently.