To undertake underwater sea chest cleaning (u/w sea chest cleaning) and underwater sea chests grating cleaning. First, the sea chest gratings are cleaned and then removed where two divers take them up to the surface. 

After that, the diver enters the sea chest and cleans. When the necessary procedure for underwater sea chests cleaning (u/w sea chest cleaning) is completed the sea chest gratings are replaced in position, giving special attention to securing arrangement. In order to make any other repair, temporary waterproofing of sea chests (plugging sea-chests) has to be made. 

The Plugging sea-chests is an effective technique, which allows any internal repairs needed in the sea chests, such as changing faulty valves, bathometer, etc. The ship remains at sea, without having to go to dry dock. After the repair, the sea chest is unplugged and tested to verify that it operates properly and if necessary plugged again.