The Sinking of U-297

[Osmium Steele]

While it had been tested on a few VIIs previously, snorkel operations were still relatively new at that time. U-297 was among the first snorkel boats lost.

If the estimated speed is even close to accurate, I'd be inclined to believe the scopes were down. Especially considering the Sunderland's first atack run failed to release any depth charges and still went undetected by U-297.

If someone had been on the scope, I'd certainly believe they would have noticed the big plane either coming or going.

Inexperienced crew, utilizing new equipment with untested operation procedures.

[Penguin]

Maybe the fate of the Sunderland is the reason why U-297's loss was so long unclear, most older literature states it was sunk by water bombs from the HMS Loch Insh and HMS Godall.

I want to add that the wake could also have other reasons than coming from the snorkel, for example it could also come from a damaged pressure tank. Hirschfeld mentioned problems like this in his book. While they were taking part in Operation Drumbeat, they had a problem like that and he said that the trail was visible for several hundred meters. I am not sure if an airplane crew can differ between those little nuances, especially not while moving fast in a combat situation.

It still is a mistake not to check the trail the sub leaves on a regular basis, so dear subsimmers: Keep an eye on the wake!

Originally Posted by Osmium Steele

Inexperienced crew, utilizing new equipment with untested operation procedures.

^This is the verdict. An almost sure death sentence in late 1944.

Btw: Does the book state what snorkel was used? Afaik the Kriegsmarine had 3 "official" types of Schnorchels, and lots of improvised ones.
10-12 knots sounds awful fast for a snorkel ride, but it would depend on the type. In "Die Festung", Buchheim wrote about several snorkel rides, but the one they used was more or less hammered together by the dock workers while Brest was already under siege. They could not even provide one for every boat. He said that they could not go more than 7,8 knots without risking to damage the snorkel.

[Osmium Steele]

Originally Posted by Penguin

I want to add that the wake could also have other reasons than coming from the snorkel, for example it could also come from a damaged pressure tank.

Possibly, however they first saw smoke at 5 miles. Most likely a snorkel.

Originally Posted by Penguin

Btw: Does the book state what snorkel was used?
<snip>
He said that they could not go more than 7,8 knots without risking to damage the snorkel.

It does not. I also believe the 10-12 knot estimate to be quite high.

I'm trying to find the email addesses of the author and both divers involved to pick their brains about some details.

[Jimbuna]

If the schnorkel was raised then the 10-12 knot speed will be wrong IMHO.

[Jimbuna]

Originally Posted by Osmium Steele

While it had been tested on a few VIIs previously, snorkel operations were still relatively new at that time. U-297 was among the first snorkel boats lost.

If the estimated speed is even close to accurate, I'd be inclined to believe the scopes were down. Especially considering the Sunderland's first atack run failed to release any depth charges and still went undetected by U-297.

If someone had been on the scope, I'd certainly believe they would have noticed the big plane either coming or going.

Inexperienced crew, utilizing new equipment with untested operation procedures.

More than likely.