IJN Armed Merchant Cruisers

[fontessa]

Seaplane tenders did not operate Rufes as aircraft carriers but did carry them as airplane transport ships. I found the photo of Rufes of the 14th Naval Air Group on 神川丸 Kamikawa Maru.

Better version of this photo shows those are aircraft from "Kamikawa Maru" own air group (see below).
"Kamikawa Maru" carried A6M2-N from August to December 1942.

Thanks for the correction.
Yes. Rufe YII-105 belonged to "Kamikawa Maru Fighter Group".
Kamikawa maru with Chitose Maru belonged to the 11th Air Group.
Chitose was the 1st Ship of the 11th Air Group.
Kamikawa Maru was the 2nd Ship.
2 Belts of YII-105 seemed to show it belonged to Kamikawa Maru.
The Rufe YII-107 next to YII-105 also wore 2 belts.
Perhaps Chitose's planes (reconnaissance planes) were YI - *** and wore one belt.
Kamikawa Maru carried 11 Rufes and 2 Petes as airplane transport ship to Shortland on September 4th.
Seaplanes Kamikawa Maru carried were placed at Shortland Seaplanes Base.
Kamikawa Maru Fighter Group was disbanded on December 7th.

In a Japanese Book 「日本海軍戦闘機隊」 大日本絵画 "IJN Fighter Groups" published by Dai Nippon Painting, the caption attached to "the photo of Rufes on Kamikawa Maru" says as below.
「神川丸」艦上の二式水戦
昭和17年8月下旬、ショートランドを目指して南太平洋を航行する水上機母艦「神川丸」艦上の二式水戦群。長期航海では定期的に行われていたという発動機試運転の様子。
"Type2 Seaplane Fighters on Kamikawa Maru"
In late August 1942, the Type2 Seaplane Fighters on board Seaplane Tender Kamikawa Maru sailed in the South Pacific toward Shortland. State of engine tests run that was done regularly in the long-term voyage.
Of course, it is possible that the above is wrong.

2式水戦 神川丸飛行隊.jpg (35.24 KiB) Viewed 914 times

零式水上観測機 神川丸飛行隊.jpg (61.52 KiB) Viewed 902 times

零式水上観測機 千歳.jpg (44.32 KiB) Viewed 902 times

fontessa

[Eugen Pinak]

In a Japanese Book 「日本海軍戦闘機隊」 大日本絵画 "IJN Fighter Groups" published by Dai Nippon Painting, the caption attached to "the photo of Rufes on Kamikawa Maru" says as below.
「神川丸」艦上の二式水戦
昭和17年8月下旬、ショートランドを目指して南太平洋を航行する水上機母艦「神川丸」艦上の二式水戦群。長期航海では定期的に行われていたという発動機試運転の様子。
"Type2 Seaplane Fighters on Kamikawa Maru"
In late August 1942, the Type2 Seaplane Fighters on board Seaplane Tender Kamikawa Maru sailed in the South Pacific toward Shortland. State of engine tests run that was done regularly in the long-term voyage.
Of course, it is possible that the above is wrong.

fontessa - thank you very much. I've never knew engines were regularly warmed up during the vouages.

[fontessa]

In a Japanese Book 「日本海軍戦闘機隊」 大日本絵画 "IJN Fighter Groups" published by Dai Nippon Painting, the caption attached to "the photo of Rufes on Kamikawa Maru" says as below.
「神川丸」艦上の二式水戦
昭和17年8月下旬、ショートランドを目指して南太平洋を航行する水上機母艦「神川丸」艦上の二式水戦群。長期航海では定期的に行われていたという発動機試運転の様子。
"Type2 Seaplane Fighters on Kamikawa Maru"
In late August 1942, the Type2 Seaplane Fighters on board Seaplane Tender Kamikawa Maru sailed in the South Pacific toward Shortland. State of engine tests run that was done regularly in the long-term voyage.
Of course, it is possible that the above is wrong.

fontessa - thank you very much. I've never knew engines were regularly warmed up during the vouages.

Agreed. I wonder Nagumo Task Forse truly continued to rotate over 360 propellars during the voyage to Perl Harver.

fontessa

[ijnfleetadmiral]

Probably not. The carriers did not have ventilated hangar decks so starting engines in the hangars would not have been a wise decision because of the fumes. I believe the only time aircraft were started in the hangars were the bombers and torpedo planes being warmed up on the elevators as they were being raised to the flight deck.

[Eugen Pinak]

Ready planed on deck definitely had their engines warmed up regularly.

As for warm-up of engines in the hangars: if all elevators were lowered and the ship was in full speed, there will be quite a wind in the hangars.

[fontessa]

Ready planed on deck definitely had their engines warmed up regularly.

As for warm-up of engines in the hangars: if all elevators were lowered and the ship was in full speed, there will be quite a wind in the hangars.

Based on the painful loss of Taiho sank by an explosion of vaporized gasoline filling her enclosed hangers, all aircraft carriers including servived Zuikahgku were equipeed with openings at the bow and the stern for the ventilations of the hangers. The propellar rotation was the last part of the "intermediate maintenance". But the removed engine was conducted it on the open "engine adjustment area".
I wold like to say something about the maintenances on
aircraft carriers (not so much) later.

fontessa

[Eugen Pinak]

Ready planed on deck definitely had their engines warmed up regularly.

As for warm-up of engines in the hangars: if all elevators were lowered and the ship was in full speed, there will be quite a wind in the hangars.

Based on the painful loss of Taiho sank by an explosion of vaporized gasoline filling her enclosed hangers, all aircraft carriers including servived Zuikahgku were equipeed with openings at the bow and the stern for the ventilations of the hangers. The propellar rotation was the last part of the "intermediate maintenance". But the removed engine was conducted it on the open "engine adjustment area".
I wold like to say something about the maintenances on
aircraft carriers (not so much) later.

fontessa

Wow! Thank new for me. I've heard about extra protection of the fuel tanks, but not extra ventilation arrangements.
With great interest waiting for anything else you can write about maintenances on CVs.

[fontessa]

[I've heard about extra protection of the fuel tanks,

In addition, Shokaku thinned the walls of the upper hangar intentionally, so that the blast would escape from there when she was hit with bombs. But it didn't work as shown in the photo below. IJN certainly lacked damage control capabilities compared to the U.S. Navy.

翔鶴 被爆.jpg (164.99 KiB) Viewed 737 times

fontessa

[ijnfleetadmiral]

The bombs that struck SHOKAKU were 1,000-pound, not 500-pound. From her official TROM:

- 0727 Ten SBDs from USS HORNET attack SHOKAKU from astern as she races north at full speed. Though three or four of the first dropped miss, nearly all of the remainder 1,000 pound bombs hit. She is heavily damaged. Four definite, possibly even six bombs struck the flight deck, one aft of the island and the rest all grouped around the amidships and the aft elevators to port of the flight deck center line. Large fires are started, and the flight deck is completely buckled, shattered and burst by the blasts, left looking like an earthquake fault zone. The center elevator is folded and ruined. On the port quarter 12.7-cm. AA guns No.6 and No.8 were completely destroyed and nearly all those nearby killed. The then fortunately nearly empty hangars are devastated by the exploding bombs. However, the strength deck holds and there is no significant damage below waterline and SHOKAKU is able to maintain 30 knots. No torpedoes are launched against her, for only the fifteen HORNET dive-bombers had found her; Nagumo's shift north had succeeded and all the rest of the American strike had missed Kido Butai and been drawn to attack the Advance Force of Kondo's two battleships and cruisers (From which the cruiser CHIKUMA would receive major damage). Since no aircraft were aboard SHOKAKU (with the exception of one torpedo plane destroyed by fire and a second at at the fantail which miraculously survived) no aviation fuel was active at the time and damage control is able to extinguish the fires after a hard fight in just under five hours and save the ship. Personnel losses, however, are extremely heavy, with more than fifty from the gunners on each side aft, and about eighty aircraft handlers and maintenance personnel in the hangars killed.

[fontessa]

The bombs that struck SHOKAKU were 1,000-pound, not 500-pound. From her official TROM:

- 0727 Ten SBDs from USS HORNET attack SHOKAKU from astern as she races north at full speed. Though three or four of the first dropped miss, nearly all of the remainder 1,000 pound bombs hit. She is heavily damaged. Four definite, possibly even six bombs struck the flight deck, one aft of the island and the rest all grouped around the amidships and the aft elevators to port of the flight deck center line. Large fires are started, and the flight deck is completely buckled, shattered and burst by the blasts, left looking like an earthquake fault zone. The center elevator is folded and ruined. On the port quarter 12.7-cm. AA guns No.6 and No.8 were completely destroyed and nearly all those nearby killed. The then fortunately nearly empty hangars are devastated by the exploding bombs. However, the strength deck holds and there is no significant damage below waterline and SHOKAKU is able to maintain 30 knots. No torpedoes are launched against her, for only the fifteen HORNET dive-bombers had found her; Nagumo's shift north had succeeded and all the rest of the American strike had missed Kido Butai and been drawn to attack the Advance Force of Kondo's two battleships and cruisers (From which the cruiser CHIKUMA would receive major damage). Since no aircraft were aboard SHOKAKU (with the exception of one torpedo plane destroyed by fire and a second at at the fantail which miraculously survived) no aviation fuel was active at the time and damage control is able to extinguish the fires after a hard fight in just under five hours and save the ship. Personnel losses, however, are extremely heavy, with more than fifty from the gunners on each side aft, and about eighty aircraft handlers and maintenance personnel in the hangars killed.

Thanks for the correction and the detailed info!

fontessa

[ijnfleetadmiral]

Anytime, my friend...it was courtesy of combinedfleet.com.

[fontessa]

I wold like to say something about the maintenance on aircraft carriers (not so much) later.

fontessa

The bellow is the maintenance system of Shokaku before the air-ground separation, that is, Shokaku had her own both air branch and maintenance branch.
The maintenance categories were the same for IJNAF and IJAAF.
The below shows Shokaku’s case.
I changed some English translations to what I think "more appropriate translations".

Works of Mechanics
Mechanics belonged to Air Branch
- Aircraft Side Maintenance
- Instrument Maintenance
Mechanics belonged to Maintenance Branch
- Fuselage / Engine Maintenance
- Ordnance Maintenance
- Elevator Operation
- Window Blocking Fence Operation
- Arresting Wires Operation
- Searchlight Operation
etc.

Major Facilities Related to Maintenance Work
補用機体格納所: Spare Fuselage Storage
補用発動機格納所: Spare Engine Storage (One spare engine for one airplane)
発動機調整所: Engine Coordination Station
See the 1st picture.

Small Scale Maintenance ‘(Aircraft Side Maintenance)
It was carried out approximately every 50 hours of engine operation including engine test runs. It's not clear where it was done. I think it's dangerous to rotate propellers at the crowded hangers. Small Scale Maintenance was conducted by mechanics assigned to Air Branch.
Medium Scale Maintenance
It was carried out approximately every 150 hours of engine operation at the “Engine Adjustment Area". The engine was removed, cleaned, parts replaced, and tested. It took about 8 hours for the former and about 1.5 hours for the latter. Medium Scale Maintenance was conducted by mechanics assigned to Maintenance Branch.
Large Scale Maintenance (Overhaul)
It was carried out approximately every 10,000 hours of engine operation. Since it could not be done on aircraft carriers, it was done at air depots similar to IJAAF.

According to the above, the Nagumo Task Force did not turn the engines during the voyage to Pearl Harbor.

翔鶴格納甲板 1.jpg (101.75 KiB) Viewed 728 times

翔鶴格納甲板 2.jpg (115.99 KiB) Viewed 704 times

翔鶴格納甲板 3.jpg (119.6 KiB) Viewed 704 times

翔鶴飛行甲板.jpg (105.46 KiB) Viewed 728 times

fontessa

[fontessa]

AHF can't attach more than 5 pictures in one upload, so I'll upload Shokaku's general layout separately.

fontessa

[Eugen Pinak]

The bellow is the maintenance system of Shokaku before the air-ground separation, that is, Shokaku had her own both air branch and maintenance branch.
...

Fontessa - thank you very much. This is really interesting.

[fontessa]

Although both IJAAF and IJNAF conducted "Air-Ground Separation", their details were different.

(1) IJAAF conducted it in 1938. It divided an Air Battalion into an Air Regiment (Air Group) and an Airfield Battalion (Maintenance / Security Groups).

(2) In the case of IJNAF, Air Branch and Maintenance Branch were not separated, and they merely left aircraft carriers. Of course, they split into aircraft carriers during operations. The below is my guess. Actually, I don't know the maintenance Branch. For example, elevator control persons were not needed on the ground, but they were needed on aircraft carriers again during operations.

海軍空地分離.jpg (80.66 KiB) Viewed 679 times

fontessa