Meaning of Abbreviation

[Roy M. Stanley II]

I have a XXI Bomber Command target chart of ships Kure, Japan in April 1945 showing BB Haruna and two camouflaged vessels annotated "OCA." Both ships scale out at about 400 feet length. One is next to the shore, the other in deep water. I can see enough of one to believe it is a warship but the other may be a mership.
Can anyone tell me what the "OCA" stands for?

[steve roberts]

Hi Roy.My Father flew with Bomber Command during the war.He often talked about being brief on alternate targets of opportunity,meaning if the main target was obscured they could bomb designated targets of opportunity.What I think OCA may Stand for is OPERATIONAL CONTROL AUTHORITY.Meaning that IJNS HARUNA would be the main target of attack,but by that time of the war,bombing tended to be fairly accurate and if the prime target was destroyed the "Master Bomber" could ask for the other two ships to be attacked by aircraft still to bomb the main target.Of course we (The British) did not have heavy bombers in the Far east.Hope this might help you out,it is of course IMHO only.
Regards Steve.

[Don Boyer]

In the United States naval jargon of WWII, the "O" designation was often used to designate and "old" type of ship: for example, the Pearl Harbor Battleships renovated and used for shore bombardment were often designated as "OBB" to differentiate them from the new fast battleships, which retained the standard "BB" designation.

Not being able to look at your chart (any chance you could post it? It's historically very interesting!) I would bet the "OCA" refers to the old sister cruisers (CA) Iwate and Izuma, both sunk in shallow water at Kure, one close to shore and one farther out in the bay.

That would be my best guess, given the jargon of the day.

By the way, ANY item floating in any part of Japan was a legitimate target in 1945, but of course the big battleships and carriers led the list. The US Navy committed many airstrikes at the end of the war to hunting down and sinking the remaining ships of the Imperial navy. Only the atomic bombs stopped them from their goal of sinking every single ship belonging to the Japanese navy, a goal the USN set itself (unwritten, unspoken) on December 7, 1941. The Army Air Force did it's share as well. Many thought these strikes a waste, as they could have been directed at destroying the kamikaze threat, but I personally feel that it wasn't much of a distraction and clearly demonstrated at least the United States Navy's commitment to compliance with their prime directive -- "execute unrestricted air and submarine warfare against the forces of Japan."

[Roy M. Stanley II]

Whole graphic is too big for this site. This cut-down section shows the two camouflaged ships and annotations.

[Don Boyer]

No idea at all what ships those could be -- can't find anything recognizably comparable in Fukui's book. Blows my OCA definition out of the water, though, as neither of those targets matches the old cruisers I was thinking of... :confused:

Regards...

[patroclus]

OCA in modern usage (e.g. "Desert Storm") is Offensive Counter Air installations. Presumably these were Anti-Aircraft capable ships.

[MelQuick]

From some of the stints I did in the service, it could have stood for On Call Always!

Mel

[FlasherTM]

OCA (3) is most likely target ship Settsu and OCA (4) is most likely Izumo since it looks like she is capsized. Iwate sank upright in shallow water near shore.

[BlackBat242]

OCA (3) is most likely target ship Settsu and OCA (4) is most likely Izumo since it looks like she is capsized. Iwate sank upright in shallow water near shore.

Except you can still see what looks like 3 funnels & a pair of masts on #4, along with having ends different from the center half of the ship. You can eve see darker areas that look like the two ships' boats in the pic below.

So it might be Iwate or Izumo.

[WGVSr]

I support Don's theory. In the vernacular of the period, ca. 1945, OCA stood for either old heavy cruiser or old cruiser, armored, which would fit the classification of the old Japanese armored cruisers. Both Izumo and Iwate were sunk at Kure in late July, 45. Azuma was badly damaged at Kre in mid-July. Settsu was sunk the same time as Iwate but all were done in by naval aviation from TF 38. Had the Settsu been specifically identified, she'd probably be noted as an OBB.
Bill