From: Christophe Chazot To: All Date: 17 Nov 02 11:54:00
Subject: Re: Info on a French sub
After TM Oliver's posts, I dug out several precise details from serious
historical sources. I re-arranged what I found in three parts, respectively
about the characteristics of SURCOUF, its operational limitations, and about
its loss. MAIN CHARACTERISTICS
length 110m, beam 9m, draught 7.18m, height from keel to top of bridge
15,44m. displ 3303 tons surfaced, 2984 tons Washington, 4318 tons submerged (all in
metric tons). max operating depth 80m (262ft), calculated limit 178m (583ft), hull crush
limit 491m (1610ft).
general arrangement : two decks, nine watertight bulkheads, pressure hull
in three trunks and 22mm thick.
eleven pairs of ballasts, with a total volume of 1027 cubic meters.
engines : two diesels, 3800hp each, two 490kW generators, two twin
electrical engines, max power 4x850hp.
fuel 361 cubic meters (more or less 288 metric tons), gasoline 2000 litres
(for the plane and the motor crafts).
batteries in 480 cells, total capacity 6550Ah.
speed 18.5kt surfaced, 8.5kt submerged.
range 10000NM at 10kt surfaced, 70NM at 5kt submerged.
crew 8 officers + 3 chief petty officers + 21 petty officers + 85 enlisted
+ 2 air crew, total 119
torpedo tubes :
4 fixed tubes (FC Mediterranee 1917 type) of 550mm (21.7in) at the bow
two turnable banks (OSd 1925 type) in the aft superstructure, each with
1x550 and 2x400mm (15.7in)
torpedoes : 14x550 and 8x400mm (all reloads were stored inside, in the
fore torpedo room)
artillery : 2x203mm (8in) in a fore turret streamlined with the bridge, powered by
hydraulic engines
trainable +/-135deg in circular, 0 to 30deg in elevation, with 300
shells, one optical telepointer
2x37mm AA detection :
one active sonar 30kHz,
one set of sixteen passive hydrophones (detection range 15000m on fast
target) three periscopes (one for search and alert, one for attack and
artillery, one small as a spare)
aircraft facilities :
one cylindrical hangar abaft the bridge for one floatplane
one mast (1929) later replaced by a collapsible crane (1938),
no catapult
plane was first a Marcel Besson MB-35, replaced (1938) by a MB-411
the spotter MB-411 was capable of 190kph (100kt), 400km, but carried no
armament total acquisition cost 86.9 millions francs
(note 1 : a REQUIN class submarine costed 20 millions, a NAIADE class 13
millions). (note 2 : SURCOUF costed half the price of a DUQUESNE class heavy
cruiser). OPERATIONAL LIMITATIONS
the first salvo of 203mm could only be fired 4mn30s after surfacing
the plane needed 25 to 30 min to be assembled, fueled, put at sea (sub had
to stop for this) and run
the turret lacked power to overcome the joints' efforts and could not be
trained if the roll exceeded 8deg
(thus the recommended limitation of +/-15deg on each side if the sea was
not still) the fire control set (telepointer + electromechanical computer) was
optimized for ranges up to 12000m
however, fire was possible up to 16000m using the periscope
for greater ranges (the guns could fire at 26000m at max elevation), the
plane was required to spot the splashes
the turret had no continuous remote control and could not follow
automatically a target
the practical number of salvoes was limited to 14 consecutive ones (28
shells in the hoisting chain)
reloading the hoisting chain from the wells let the sub exposed on
surface for too long
the external TT could only be reloaded when the ship was in sheltered and
calm waters because of its heavy topweight (turret : 198tons), trim was very difficult
to handle the huge superstructure generated additional trim problems when the sub
dived or surfaced
crash dives were too long because of the large number of ballasts
THE LOSS OF SURCOUF
SURCOUF was lost between February 12th and 19th, 1942, to an unknown cause,
roughly in 11N-079W, with all its crew. It had passed east of Guantanamo and
was heading to Balboa, on a transit from Saint-Pierre to Tahiti and Noumea.
Its last message was sent on Feb.12th. According to this message, on Feb
17th at 13:00 the sub was to be 340NM NNE of Panama, running at 7.5kt on
the surface, and was to reach Balboa on the evening of the 19th.
It was first believed that the SURCOUF had been rammed at night by the cargo
USS THOMPSON LYKES, and this is still the most commonly cited cause of its
loss. By the way, several points don't comply with this scenario :
(1) the THOMPSON LYKES did hit something at 22:30 on Feb.18th, in
10:40N-079:31W, but the pictures I saw of its bow in drydock show only minor
damage (some crancked plates, the underwater bow itself slightly bent about
3ft to starboard, practically no damage above waterline). Since the THOMPSON
LYKES had more or less the same size (4700t, 125m) than SURCOUF (110m), and
that SURCOUF had a solid pressure hull, there's no doubt that a collision
between them should have caused a much greater damage.
(2) OOD of the THOMPSON LYKES said that the incoming ship crossed the route
of the cargo (then heading 015 at 13kt to Guantanamo). This does not comply
with the route of the SURCOUF, that was 210.
(3) the bridge of the SURCOUF was as high as that of THOMPSON LYKES, and the
OOD and watchers of the cargo only sighted a small hull.
(4) the collision did not slow down the THOMPSON LYKES.
(5) no wreckage was found by the THOMPSON LYKES that stayed more than 9
hours near the accident. One man was briefly sighted but could not be
rescued. Considering this, my conclusion is the same than TM Oliver : SURCOUF was not
rammed by THOMSON LYKES.
So what? Other possibilities have been evoqued. Among them, SURCOUF could
have been mistaken for a U-Boot by a patrol plane. Two A17 and one B18 from
Rio Hato did attack a "very large submarine" 50NM North of Panama at 07:13
on Feb.19th. At this time, SURCOUF was supposed to be 30 to 50 NM from
Panama. This could be the truth, but no evidence has ever been found since
no serious investigation was led. One of the pilots confirmed in 1990 that
he had bombed and sunk a surfaced sub there, that's all. Several corpses
were found on the coastline by civilians some days later, and they were
buried without any form of identification.
Such confusions occurred : french subs CENTAURE, CONQUERANT and PERLE were
all three mistaken for U-Boote and sunk by US forces during the war - as
some US subs were.
The loss of SURCOUF will remain a mystery, except if the wreck is found one
day or a serious investigation is made - 60 years later!
If someone wishes me to post some picture on alt.binary.pictures.military or
to give further details on the sub, please tell.
Regards, Christophe
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