Sinking the Shinano 11-29-1944

ancient46 · 10-02-08, 01:11 PM

From the Official Patrol #5 Log of the SS Archerfish CDR Joseph F Enright commanding, to COMSUBPAC. Source: www.ussarcherfish.com

November 28, 1944
1718 Surfaced.
2034 Sighted Inamba Shima. Distance about 12 miles but no radar contact.
2048 Radar contact 24,700 yards, 028° T. Started tracking from ahead. Ship
Contact #4.
2140 Identified target as aircraft carrier, base course 210, speed 20. It appeared he only had one escort. With sky overcast, and dark horizon to north, started surface approach on starboard flank.
2230 Escort on starboard beam sighted. Not possible to make surface approach on this side. Changed course back to his base course.
2250 Target group closing and we are off the track too far to submerge. Carrier turned on red truck light for about 10 seconds, then off for 20, and on again for 10. Range to closest escort 6100 yards and to carrier 15,000. Sent lookouts below and watched for gun flashes or splashes. Escort continued to ignore us - Called lookouts back.
2300 Enemy group now determined to consist of large carrier and 4 escorts. One on either beam, one ahead and one astern.
2330 Sent contact message.
2340 Looks like big zig in our direction.
2400 Probably a base course change to the west. We are now on his port flank further off the track than before. Changed our course to 270 and coaxed a few more turns from the already overloaded motors.

November 29, 1944 From here on it was a mad race for a possible firing position. His speed was about one knot in excess of our best, but his zig plan allowed us to pull ahead very slowly.
0241 Sent second contact message when it appeared he planned to stay on 275 and not much chance of us reaching a firing position.
0300 Looks like another change of base course or big zig to southward. Range closing rapidly and we are ahead.
0305 Changed course to 100 and submerged. Range to carrier 11,700 yards. Sighted carrier in periscope at 7000 yards. Changed course 10° to left to keep from closing track too much. A small starboard angle on the bow and range 3500. Escort closed carrier to receive blinker message. This caused him to pass nicely ahead of us at 400 yards.
O316 Carrier zigged away about 30°. Picture improves. Good positIon, 70 starboard track, 1400 yards. Gyro shots necessary due to late favorable zig.
0317 Started firing all bow tubes, MK 14 torpedoes, set depth 10 feet - First gyro 28° right, track 100, spread from cards, aft to forward.
0317-47 Heard and observed first hit just inside stern near props and rudder. Large ball of fire climbed his side.
0317-57 Second hit observed and heard. This was about 50 yards forward of the first.
With hits seen, a destroyer about 500 yards on our quarter, and wakes visible, started deep.
Four more properly timed hits on our way down. The time corresponded to the firing interval and sounded the same as the two that were observed. The six hits with a spread can be explained by considering the data as correct, the overall spread from the card for 600 foot target is 10° and our target, 750 feet long is 10½° at 1400 yards.
The six hits are certain.
Breaking up noises started immediately.
With the bright moonlight the identification is quite accurate. The carrier appeared to be similar to the Hayntaka class except it is believed to had a raked stern. Perhaps our recco plane over Yokohama has a picture to further identify this one.
0325 Started receiving a total of 14 depth charges. Closest one was perhaps 300 yards away.
0345 Last depth charge. The hissing, sputtering, and breaking noises continued. At one time they covered 90° of scale on the sound receiver.
0405 Last breaking up noise. Our starboard sound head training gear damaged by a broken roller and a holding down lug. Either from depth charge or pressure. Both training motors grounded out by bilge water as it was necessary to use a 10° up angle. Credit is claimed for a sinking because of these items:
(a) Six certain hits. (2 observed)
(b) Heavy screws stopped and did not restart.
(c) Loud breaking up noises for 47 minutes.
(d) Escorts give us slight attention and closed carrier, probably picking up
survivors.
0610 Daylight and first periscope observation. Nothing in sight.

Does anyone have copies of the spread cards used for this historic sinking? Are they adaptable for use in SH4? I found a formula for calculating spreads in the Torpedo Firing Manual that could be used to construct the cards but not the cards Enright mentioned.

10-02-08, 01:11 PM	#1
ancient46 Officer Join Date: Apr 2008 Location: Pennsylvania Posts: 239 Downloads: 108 Uploads: 1	Sinking the Shinano 11-29-1944 From the Official Patrol #5 Log of the SS Archerfish CDR Joseph F Enright commanding, to COMSUBPAC. Source: www.ussarcherfish.com November 28, 1944 1718 Surfaced. 2034 Sighted Inamba Shima. Distance about 12 miles but no radar contact. 2048 Radar contact 24,700 yards, 028° T. Started tracking from ahead. Ship Contact #4. 2140 Identified target as aircraft carrier, base course 210, speed 20. It appeared he only had one escort. With sky overcast, and dark horizon to north, started surface approach on starboard flank. 2230 Escort on starboard beam sighted. Not possible to make surface approach on this side. Changed course back to his base course. 2250 Target group closing and we are off the track too far to submerge. Carrier turned on red truck light for about 10 seconds, then off for 20, and on again for 10. Range to closest escort 6100 yards and to carrier 15,000. Sent lookouts below and watched for gun flashes or splashes. Escort continued to ignore us - Called lookouts back. 2300 Enemy group now determined to consist of large carrier and 4 escorts. One on either beam, one ahead and one astern. 2330 Sent contact message. 2340 Looks like big zig in our direction. 2400 Probably a base course change to the west. We are now on his port flank further off the track than before. Changed our course to 270 and coaxed a few more turns from the already overloaded motors. November 29, 1944 From here on it was a mad race for a possible firing position. His speed was about one knot in excess of our best, but his zig plan allowed us to pull ahead very slowly. 0241 Sent second contact message when it appeared he planned to stay on 275 and not much chance of us reaching a firing position. 0300 Looks like another change of base course or big zig to southward. Range closing rapidly and we are ahead. 0305 Changed course to 100 and submerged. Range to carrier 11,700 yards. Sighted carrier in periscope at 7000 yards. Changed course 10° to left to keep from closing track too much. A small starboard angle on the bow and range 3500. Escort closed carrier to receive blinker message. This caused him to pass nicely ahead of us at 400 yards. O316 Carrier zigged away about 30°. Picture improves. Good positIon, 70 starboard track, 1400 yards. Gyro shots necessary due to late favorable zig. 0317 Started firing all bow tubes, MK 14 torpedoes, set depth 10 feet - First gyro 28° right, track 100, spread from cards, aft to forward. 0317-47 Heard and observed first hit just inside stern near props and rudder. Large ball of fire climbed his side. 0317-57 Second hit observed and heard. This was about 50 yards forward of the first. With hits seen, a destroyer about 500 yards on our quarter, and wakes visible, started deep. Four more properly timed hits on our way down. The time corresponded to the firing interval and sounded the same as the two that were observed. The six hits with a spread can be explained by considering the data as correct, the overall spread from the card for 600 foot target is 10° and our target, 750 feet long is 10½° at 1400 yards. The six hits are certain. Breaking up noises started immediately. With the bright moonlight the identification is quite accurate. The carrier appeared to be similar to the *Hayntaka* class except it is believed to had a raked stern. Perhaps our recco plane over Yokohama has a picture to further identify this one. 0325 Started receiving a total of 14 depth charges. Closest one was perhaps 300 yards away. 0345 Last depth charge. The hissing, sputtering, and breaking noises continued. At one time they covered 90° of scale on the sound receiver. 0405 Last breaking up noise. Our starboard sound head training gear damaged by a broken roller and a holding down lug. Either from depth charge or pressure. Both training motors grounded out by bilge water as it was necessary to use a 10° up angle. Credit is claimed for a sinking because of these items: (a) Six certain hits. (2 observed) (b) Heavy screws stopped and did not restart. (c) Loud breaking up noises for 47 minutes. (d) Escorts give us slight attention and closed carrier, probably picking up survivors. 0610 Daylight and first periscope observation. Nothing in sight. Does anyone have copies of the spread cards used for this historic sinking? Are they adaptable for use in SH4? I found a formula for calculating spreads in the Torpedo Firing Manual that could be used to construct the cards but not the cards Enright mentioned.