IJN water-tight doors

[chuck]

Does anyone know the reason why many IJN watertight doors and hatches are pierced with escape man-holes? No one else appears to have provided water-tight doors with such seemly self-defeating gestures of mercy. It seems to me that opening the man hole in the door to let people through would compromise water-tight integrity as much as opening the door itself.

[BattleshipHistorian1]

Chuck:

A good question! In reality, ALL navies have such watertight doors- I had to deal with and restore many on the NEW JERSEY during my period of restoring her for public museum display, and saw many others in fairly new USN vessels (late 1970's-early 80's construction) in the Philadelphia naval reserve fleet. The reason for this type of "door within a door' is simply this- the larger watertight doors are typically kept battened down tight during increased periods of watertight integrity, but- say a 40mm clipping room or other compartmant such as internal communications rooms- access is still necessary even during high conditions of readiness at sea, so the manholes allow one person to efficiently and quickly enter/leave a particular area without opening up the entire door.

There are several types of watertight doors, the typical being:

Manual Dogging Type (WTD): Each "dog" or latch on the W/T door (typically six to eight) is opened/closed individually. Getting these in place takes some time, and is done using a "dogging wrench" (a piece of pipe) to really get them battened down tight. These doors are the ones which typically have the extra w/t (water-tight) manhole cover in them, but are fairly rare (one out of ten doors have an additional w/t manhole "escape hatch" set into them, and are usually set horizontally into decks to allow access from one level or deck to another.)

Quick Acting Water tight door (QAWTD): These are just like the above doors, but have all their dogs connected on one side to a central wheel, which is used to seal the dogs down all at once. These are typically seen on vertical surfaces such as bulkheads and in passageways- not doors leading into any magazines, IC (internal communications) or other high value areas. They needa lot (constant) maintenance to keep them operated correctly.

Water-Tight Escape Hatch (WTEH): The rarest types of doors, typically found in very tight, infrequently accessed areas, usually used only for inspections of shaft alleys, double bottom areas, torpedo blisters, etc. They can look exactly like the type you are referring to in regular W/T doors, but are typically found bolted down tight- no "dogs" or handles.

I know the IJN used quit a few of these doors as well, in general they all look and act pretty much the same; the IJN did have a tendency to use more of the "door within a door" types, and I strongly suspect it was to allow the pass-through of AA Ammunition, etc. during periods of high alert. It should be noted that in all services, when under the highest state of combat readiness (Condition "Zebra" in the USN in WWII, now called Condition "ZED" today in USN parlance) ALL doors are cranked down tight and NO doors are allowed to be opened without getting prior permission from the Damage Control Central- and you didn't ask if you had to take a pee! Generally, in those situations, only the passage of ammunition, or to relieve overheated crew (such as boiler crew) or casualties to the Ward allowed any doors to be opened. Doors were never opened and left open, either- whatever had to be done was done double-timed, and then W/T integrity would be quickly restored.

[Gone Asiatic]

Condition "Zebra" in the USN in WWII, now called Condition "ZED" today in USN parlance)

Think you got that backwards.....

[BattleshipHistorian1]

I believe that your right, my good man! Thanks for catching that!