In some situations, it is necessary to pierce bulkheads to allow crew or passengers through. In this case, a sliding watertight door is installed. An example of this situation is the watertight door that is found on some ships between the machinery space and the shaft tunnel. Liners have many of these doors that allow passengers to go between the different sections of the ship. These watertight doors are usually hydraulically activated. Local control stations must be located on either side of the door. In addition, a remote control station (generally located in the wheelhouse) must be placed outside both compartments separated by the watertight bulkhead.

Chapter II-1, Regulation 15 of the SOLAS Convention governs the installation and operating requirements for these doors.

Extract, Regulation 15,

[A watertight door] shall be provided with an audible alarm, distinct from any other alarm in the area, which will sound whenever the door is closed remotely by power and which shall sound for at least 5 s but no more than 10 s before the door begins to move and shall continue sounding until the door is completely closed. In the case of remote hand operation it is sufficient for the audible alarm to sound only when the door is moving. Additionally, in passenger areas and areas of high ambient noise the Administration may require the audible alarm to be supplemented by an intermittent visual signal at the door; and

shall have an approximately uniform rate of closure under power. The closure time, from the time the door begins to move to the time it reaches the completely closed position, shall in no case be less than 20 s or more than 40 s with the ship in the upright position.

Watertight bulkhead

Watertight door operating mechanism