View Full Version : IJN submarine cruiser or else ?

04-03-2009, 07:36 AM
A frriend of mine at subsim claims to have received this photo in 1999, and that it is an Imperial Japanese Navy Submarine.

I furiously looks like the french Surcouf even if the turret is more slanted.

any ideas ?


04-03-2009, 03:58 PM
A frriend of mine at subsim claims to have received this photo in 1999, and that it is an Imperial Japanese Navy Submarine.

I furiously looks like the french Surcouf even if the turret is more slanted.

any ideas ?


I think the picture is of M2 aka X2. British, based on a converted K-Class Hull. Two turreted versions were produced, one with 1x 8-inch gun, one with 2x 6-inch guns.
The one with the 6-inch guns was later converted further as a seaplane carrier, with the hangar replacing the turret.

This could be a rare picture of that submarine before it was converted to the seaplane carrier configuration.

Surcouf was essentially a French copy of the same vessel, though about 10% larger, IIRC.

(Source for this is Purnell's : Submarines since 1919.)

I have no recall whatsoever of the IJN having a submarine in the Surcouf/X2 class, as a U-Cruiser.

Regards, Uyraell.

Major Walter Schmidt
04-05-2009, 11:24 AM
Thats from a movie, Loreli...


in the movie it was called I-507(fictional)...
The setting was that the sub was a modification of a captured Surcouf.

04-07-2009, 10:23 AM
link on subsim :

image :

Denis says he received that picture in 1999, so that's 6 years before Lorelei was made, I have that movie and also thought it was that boat, I asked Denis and he said that it wasn't.

any other ideas ?


Major Walter Schmidt
04-07-2009, 05:07 PM
Thats really weird >>
The thing on the back of the conning tower, resembles the Type N Mini Sub from the movie, and all the elements match.
Maybe its a photo from pre production? or maybe he got the date wrong...

10-15-2010, 02:47 AM
Link to video of the M2, compare size of deck!



10-17-2010, 04:45 PM
I watched the clip.
Unfortunately, it shows M2 post-conversion.
A clip showing M2 prior to conversion would be extremely useful.
That said, I'm of the opinion any such clip, or photograph, would be a rare find indeed, if it exists.

For years, on and off, I researched both M2 and M1, mainly from interest that the British were so innovative, not a trait the UK was noted for back then, or at least, not a trait or which many records/documentation survives.

It always struck me as odd that it was the French and Japanese that picked up the concept and furthered it, even though both those nations were also ultimately less than optimally successful.

Thus my interest when this thread was originally opened.

Further research after I posted above has turned up pre-conversion photos of M2, dated 1920.
It is very very plain, from looking at those pictures, that the photo this thread OP shows is based on the Surcouf.
With that, I'm satisfied the matter ends there.

Respectful Regards, Uyraell.

10-18-2010, 12:02 PM

IJN did not have turreted submarines.

The large cruiser submarines (Junsen, Ko-Gata, Otsu-Gata and Hei-Gata classes) were built for the planned decisive naval battle against the US-Navy. Recon aircraft were rated more useful for this task in the large Pacific Ocean. So most cruiser submarines were equipped with a hangar for at least one aircraft and not with gun turrets.

The Sen-Toku class submarines were the largest submarines of WW2 (around 40% larger than Surcouf) and these were also planned as aircraft carrier for 3 specially designed dive bombers.


tom! ;)

05-11-2012, 03:52 AM
Right, but indeed, there was an I 507 in the IJN, NOT FICTIONAL, Cagni class italian submarine., named Ammiraglio Cagni, , built by CRDA Monfalcon and launched on 20 July 1940 , surrendered to the Japanese off Colombo in september 1943, renamed as I-507, broken up in 1948-.

Completely to the IJN service, she was renamed as I-507 and used as school ship, because to her low speed impeded serve for another function. Mussolini tried to recover to the Cagni in 1944, but the Japanese refused this.
In July 1945, she was attacked and sunk by 2 B-25 bombers in the shallow waters of the Gōtō Islands. The hull was raised by the U.S in November 1945 (two months after the Japanese surrender) and scrapped in 1948.

These submarines were designed as commerce raiders for oceanic operations. They had high endurance and a large torpedo load for extended patrols. A smaller 450 mm torpedo was chosen, rather than the standard 533 mm, as the Italians believed this was adequate to deal with merchant ships. The boats were designed to have the range to sail non-stop from Italy to Kismayu, Italian Somaliland where a new submarine base was to be built. In order to operate in the Indian Ocean Monsoon the submarines were fitted with large conning towers and armed with two 100 mm guns.
The large conning towers were rebuilt to a smaller German style as a result of war experience. The Ammiraglio Cagni carried out a 4.5 month patrol in the South Atlantic during 1942-43. The other three boats were used as transport submarines to supply Italian forces in North Africa.