Calling all Japanese pre-war/wartime Merchant Marine fans

[Gilbert]

Off-line, Motoyukisan has ID'd this ship as Kumagawa Maru. Anyone know if there are sister ships? He has also provided another set of photos of Rikko Maru from the same 1939 issue of Sea and Sky

Dan, firstly thanks for the pictures and to Motoyuki san for identifying Kumagawa Maru. The answer to your question is : yes, Three sisters.

Kumagawa Maru was the second ship of the Uyo Maru class and was completed on 31/03/1934 as Nichiyo Maru, still owned by Toyo Kisen K.K. she was renamed in 1940.

Please find below some details about the four ships of this class:

- Uyo Maru-7504Grt-LPP=132.6m-B=17.8-D=9.8-Machinery=1D-service speed 13.5knts.-completed on 03/10/1933 as Uyo maru-owner Toyo Kisen K.K.-registry port, Tokyo-renamed Shinanogawa Maru in 1940-used as a civilian merchant ship-fate=sunk 14/11/1942, Off Tassafaronga @ Guadalcanal by USAAF + USMC + USN aircraft from "cactus airforce".
- Nichiyo Maru-7509Grt-LPP=132.6m-B=17.8-D=9.8-Machinery=1D-service speed 13.5knts.-completed on 31/03/1934 as Nichiyo maru-owner Toyo Kisen K.K.-registry port, Tokyo-renamed Kumagawa Maru in 1940-converted to a "Kaigun Ohkyu Yusosen" (xAO)temporary tanker on 13/02/1943-fate=sunk 12/01/1945 Off Cape St. Jacques @ French Indochina, 10.00n 106.00e by US TF.38 / Aircraft.
-Getsuyo Maru-7509Grt-LPP=132.6m-B=17.8-D=9.8-Machinery=1D-service speed 13.5knts.-completed on 04/06/1934 as Getsuyo maru-owner Toyo Kaiun K.K.-registry port, Tokyo-renamed Mogamigawa Maru in 1936-Requisitioned by IJN and used as a "Tokusetsu Fusetsukan" (ACM) until 10/02/1942 and as a "Tokusetsu Kokuki Umpansen" (IJN aircraft transport) from then till her loss-Fate sunk on 31 July 1943:
"South China Sea. N of Truk. At 2307, LtCdr (later Rear Admiral) George H. Wales�s USS POGY (SS-266) torpedoes and sinks MOGAMIGAWA MARU by the stern at 11-04N, 153-18 E."
- Tenyo Maru-6843Grt-LPP=132.6m-B=17.8-D=9.8-Machinery=1D-service speed13.5knts.-completed on 28/03/1935-owner Toyo Kisen K.K.-registry port, Tokyo-Requisitioned by IJN and used as a "Tokusetsu Fusetsukan" (ACM)-Fate sunk on 10/03/1942 off Lae, New-Guinea by Aircraft from CV-2 Lexington and CV-5 Yorktown.

Cheers
Gilbert

[Gilbert]

And here is a painting of Kumagawa Maru by Ueda Kihachiro

Gilbert

[Dan K]

Excellent. Thx, Gilbert.

[Graham Boak]

I've just obtained a Hasegawa Heian Maru. It suggests the decks are tan. Is this also the considered opinion of the board, or should they be grey? I'm thinking that if the carrier decks weren't camouflaged, neither would these be.

[Gilbert]

I've just obtained a Hasegawa Heian Maru. It suggests the decks are tan. Is this also the considered opinion of the board, or should they be grey? I'm thinking that if the carrier decks weren't camouflaged, neither would these be.

Graham,

I would follow Motoyuki san kit's model colours : http://ww6.enjoy.ne.jp/~iwashige/heianmaru.htm

Regards
Gilbert

[Graham Boak]

Yes of course, I should have thought of that.

There are a number of points of difference. The reduction in the number of lifeboats makes sense, but two of the main guns are in a different position - forward rather than aft. This does seem consistent with other vessels. The AA is differently placed too, with better firing arcs, though I do wonder a little about the structure on top of the bridge for a multiple mount. The interpretation of the camouflage pattern differs too.

Entire agreement on teak decks, however.

[bootneck42]

Hi Graham,

I read somewhere, possibly on this or the j-aircraft.com site, that the wood used for Japanese vessels was a redwood. This gave the decks a deeper tone rather than the light colour of teak.

Can anyone else confirm this?

Hope you enjoy building the Heian Maru

Mike (bootneck)

Here is an example of the deck of Yamato - a large scale model in Japanese museum

[Gilbert]

Hi Graham,

I read somewhere, possibly on this or the j-aircraft.com site, that the wood used for Japanese vessels was a redwood. This gave the decks a deeper tone rather than the light colour of teak.

Can anyone else confirm this?

Mike,

It depends of the ships. Yamato, had a Hinoki Cypress wood deck which tends to "greyish" when weathered but most of IJN ships wood decks used Bei-matsu (pine) which tends to "dark(ish)". Anyway, as you stated, the tone is different from a light teak colour.

HTH
Gilbert

[Ron Wolford]

Hello Everybody
Graham, for what it worth, here are a couple of black and white photos of the promenade deck of a Heian Maru Class ship. Not sure what type of wood they used, but I think it was a light color wood. Also the number two hold is capped with a steel sheet, the only entry is a long (as long as the hold)narrow cut out just wide enough for the torpedo to be pull out through.
A. Entry and Exit hole for Torpedoes
B. High pressure cylinders
C. High pressure Torpedo Charging Station (I think) This little building sits between the Number 2 hold and the front part of the superstructure. It is about twice as tall as the hold and has 2 hatches on the front.
D. Three exercise Torpedo Warheads.
If you are modeling her as she was, when sunk, do not place the large deck guns alongside the Number 2 hold. They were removed sometime in 1943 (I personably do not think that they were ever installed there, but that is just my opinion). I have some bad underwater photos of this area, and if you want I can post them but it's hard to make anything out. Please post a photo when you get her built. Thanks

Ron Wolford


Heian Promenade deck 1
http://i50.tinypic.com/ofpksj.jpg

Heian Promenade deck 2
http://i46.tinypic.com/2ztee1e.jpg

[DougKn]

How close is Heian M. to sister Hikawa Maru's current decks? There were some pictures taken by a visitor a couple of years ago. Sorry, I don't remember who it was to give proper credit to.

[Graham Boak]

Thanks for the information. I picked this up at a bargain price, and it isn't near the top of the build list, but fingers do itch....I thought this would be a straightforward build to play with camouflage, but I should have known better. I have made the original boxing: I thought I'd made the passenger liner too but if so it seems to have sailed away out of the storage.

I don't care too much for the very light appearance of the WEM Oak decks, so I'm grateful for the suggestion to tone it down.

I'll modify the hatch for the number 2 hold, and leave off the guns. The instructions have them not there but at the rear - I presume this aft placing is just wrong, leaving her with just the two big guns.

One point does intrigue me and that is the AA fitting. Was the bridge top strong enough to take the triple mounting, as offered? Or even the twin, as seen in Motoyuki-san's book? I suppose that some strengthening would have been easy enough, and it is clearly the best position for a good field of fire. However, were there no other AA mountings? Two seem very light, and extra positions to the rear of the superstructure would seem obvious. Was it just that prewar assumptions were retained without upgrading before her loss?

[Gilbert]

One point does intrigue me and that is the AA fitting. Was the bridge top strong enough to take the triple mounting, as offered? Or even the twin, as seen in Motoyuki-san's book? I suppose that some strengthening would have been easy enough, and it is clearly the best position for a good field of fire. However, were there no other AA mountings? Two seem very light, and extra positions to the rear of the superstructure would seem obvious. Was it just that prewar assumptions were retained without upgrading before her loss?

Her AA armement varied during the war. According to her TROM "23 October to 7 November 1943:
Yokosuka Navy Yard. Refitted. Four 152-mm guns are replaced by one 120-mm AA gun (10th Year Type), two Type 96 25-mm twin mounts and two Type 93 13.2-mm twin mounts In addition, a Type 2 sonar is installed. The crew complement is increased to 242 men. HEIAN MARU's dazzle camoflague pattern is possibly applied at this time."

Gilbert

[Dan K]

An unshielded twin 25mm mount weighs approx. 4000lbs. Chances are that a little reinforcement was needed but, bridge trusses and planking are close together so, its probably pretty sturdy to begin with.

Model Art has released booklet #4 on merchants, this one covering Hikawa Maru. Some recent color pics show the wood on the covered promenade deck to be new or restored. Color is a light to meduim wood tan.

[Graham Boak]

Gilbert: the TROM is somewhat confusing, at least to me. I have no reference suggesting that the Heian Maru had more than four such guns (although six different positions are suggested), but other(s) that say two. Two may mean originally six minus this four, but if the TROM means that all the 152mm guns were removed, then the 120mm gun would presumably go on the aft mount (and can be modelled by any convenient, presumably open, weapon) but what would happen to the front position? Would this be modified to be a position for the two twin 25mm? The photo in Motoyuki-san's book does perhaps suggest a lower structure on the forecastle than aft. Also, are these four AA mountings to be taken as the total AA defence, or were they placed on the mountings of the replaced 152mm and additional to that already present - and if so, what was this?

I certainly want to do her camouflaged, and am happy with the two lighter AA on top of the bridge, if only because it appeals to my prejudices on the matter! I find the positioning of the mountings in the Hasegawa kit (behind the bridge) somewhat doubtful, as better fields of fire could be found on the aft superstructure. If two 152mm guns were retained (which means she started with six...which no-one says), this would perhaps be the best place for the 120mm, and the Hasegawa position becomes more logical.

Option 1: 120mm aft, new platform with 2xtwin 25mm forward, 2xtwin 13.2mm in bridge wings

Option 2: 2x152mm, 1x120mm aft superstructure, 2xtwin 25mm behind bridge, 2xtwin 13.2 bridge top.

The first seems to be the best fit, but both seem a little light in AA for late 1943. I'm inclined to add another couple of twins in the position of the lower removed 152mm, and/or even retain the pair in the Hasegawa position, but somewhere there is a cross-over from making reasonable assumptions in the face of limited conflicting information, and building a "what if". Comments?

[Gilbert]

Graham,

If you look at her TROM and click on her name , you will get access to her data including her armament:
"Six 5.9-inch (150-mm) single mount guns, one 3.5 m range finder, two dual 13.2-mm machine guns. In 1943 changed to one 120-mm AA gun (10th Year Type), two Type 96 25-mm twin mounts and two Type 93 13.2-mm machine gun twin mounts."

Therefore, as four 15cm guns wer removed in november 1943, to me, she retained 2 15cm guns afterwards + the other guns stated in her TROM. Motoyuki-san's model depicts her in mid-1943 with four 15cm guns and two dual 13.2mm on top of bridge. I would go, if you want to depict her as in late 1943, with the following gun configuration:

Option 3: 2x152mm (behind forward mast), 1x120mm aft superstructure, 2xtwin 25mm front platform, 2xtwin 13.2 bridge top.

But I agree on the lack of photo evidence to support this configuration. However, it seems logical to have a front platform with AA guns as many "Marus" were fitted with such a light AA configuration.

HTH
Gilbert

[Graham Boak]

Thanks, though I still find the text ambiguous regarding whether the AA described in October 1943 was additional or total, and the TROM does not support either source showing four big guns. She either had six, or two. I did find this dive report on the wreck
http://www.michaelmcfadyenscuba.info/vi ... age_id=229
It suggests ("turret") that the 152mm guns were still on the end platforms, at least the bow, which rules out the 2xtwin AA in this position. They were not found on the hold decks - as indeed Ron advised. It also places the AA exactly where Hasegawa has them despite my doubts, but at least I did qualify that for the 120mm being aft.

Option 4: single 152mm on each endcastle (as kit), 120mm on aft superstructure (exact positionmounting unknown), 2xtwin 25mm aft of bridge (as kit), 2xtwin 13.2mm on bridge ends (as Motoyuki-san). Perhaps another pair of twin 13.2mm?

Seeing how much AA some of the supply ships carried, she still seems underarmed for an auxiliary, but if the records and the wreck agree (to that extent), so it must have been.

[Gilbert]

Graham, thanks for the link. I agree now after reading the divers' report about the 15cm guns position. What still troubles me, in this case, is the positioning of the 12cm gun. Looking at Motoyuki-san's model I don't spot any clear and logical place aft of the rear superstructure for it but it might be possible to place it behind the funnel, on a platform, just aft of the two "ventilators". On the other hand, regarding the number of light AA guns, I remember reading an article saying that the Japanese were encountering severe shortages by mid 1943 for these AA guns and Marus captains were complaining about this situation. On the other hand, if you look at Ueda-san and Yuki-san paintings, some auxiliaries are well-fitted with AA guns, other don't have many aboard.
Therefore, unless some new evidence appears, I would stay with 2 twin 25mm and 2 twin 13.2mm, but, once again, it's only my two (euro)cents.

Gilbert

[Gilbert]

@ Graham and all interested by Heian Maru,

I just got an e-mail from Gengoro S. Toda which will hopefully clarify her final armament. Its seems the TROM is in error resulting from a misinterpretation of Fukui's statement. Gengoro-San says the following :

" Heian Maru was originally fitted with four 15cm guns and two 13mm twin AA guns.
Armament was changed starting on 23 Oct 1943 and completing on 7 November 1943 at Yokosuka.

Four 15cm guns were all removed.
Two 12cm AA guns were newly fitted.
Two 25mm twin AA guns were newly fitted.
Two 13mm twin AA guns were moved to the other position.

It seems to me that two 13mm twin guns were originally fitted on the bridge.

So final position of armament may be:-

Two 12cm AA guns (bow and aft?)
Two 25mm twin AA guns (on the bridge?)
Two 13 mm twin AA guns (?)"

To me, this makes full sense with Motoyuki-San model and hopefully clarify her post refit gun arrangement. Regarding the diver's report with the "turrets" still in place on the wreck, maybe they spotted a gunshield and called it "turret" instead but I will rather rely on Gengoro-San statement.

Gilbert

[Graham Boak]

Thanks. That does make the number and type of guns clear, if not the positioning.

120mm AA guns with shields? Odd. Other IJN examples would be interesting, as a guide. I don't know of any. Like you, I presume there must have been something present to justify the use of "turret", whatever interpretation we then put to the word.

Motoyuki-san's (and indeed Hasegawa's) model is of the early configuration but with camouflage appropriate to the later fit, if we are to believe that aspect of the text.

The phrase "moved to the other position" suggests to me that the twin 13mm were placed on the deck where the 152mm had been mounted. So fore or aft? Ron suggests not forward - but aft leaves me convinced that a better position is one deck higher. Time and effort may have counted against that, perhaps?

Ah well, I only had one pair of parts suitable for the lighter AA anyway.

[DougKn]

From the Pete Mesley Dive website: http://www.petemesley.com/truklagoonwrecksHEIAN.htm, They have a drawing of Heian as she looks today, lying on her port side. The gun tubs fore and aft are noted as empty (they could have been salvaged. though) and there is one gun lying on the port side near hold #3. Looks like a 120mm in their drawing, but could be anything, and could have fallen from anywhere. Hope this may provide a little bit more insight.