Tirpitz accompanies Bismarck in Operation Rheinubung

[Bgile]

A fair amount of Bismarck's main (lower) armor deck would be "shaded" by her upper side belt at ranges of 25,000 yds or so. If you are going to assume that a shell hitting the upper deck would be deflected downward when penetrating that deck, you have to also assume the upper side belt would deflect shells into a flatter trajectory, making penetration of the lower deck very problematic.

[RF]

The problem with this is if the Germans haven't shown up in a day or two then the British are left with two possibilities.
1) The Germans have broken into the Atlantic.
2) They haven't.
In the case of 1 there's not a whole lot they can do until they get more intelligence. The Atlantic is just too big. However if the Germans are still north of Iceland and especially given a CV for scouting then there is a good chance of trapping them. Especially since more (small) units will have been showing up. There is also the chance that a random fishing or patrol boat or plane will spot the Germans. In this case they risk being cornered in narrow seas.

The ocean north of Iceland, where the Atlantic borders the Artic Ocean is also a very wide sea area. Granted the British would have the advantage of the very long daylight hours, but the Germans holding area was in the region of Jan Mayan Island and Spitzbergen, beyond the range of land based aircraft. Also the proximity of northern Norway affords the Germans some air cover. And remember this was the time before the Arctic convoys to the USSR started.

[lwd]

Looks to me like if you go north of Iceland the total distance from Greenland to Norway is less than 5-600 miles. A CV should be able to do a decent job of checking out everything within say a 200 mile radius weather permiting. Then there is sea ice to consider.

[Bgile]

Looks to me like if you go north of Iceland the total distance from Greenland to Norway is less than 5-600 miles. A CV should be able to do a decent job of checking out everything within say a 200 mile radius weather permiting. Then there is sea ice to consider.

What aircraft were available for that purpose and what was their range? Would that subject the CV to Luftwaffe attack?

[David89]

A fair amount of Bismarck's main (lower) armor deck would be "shaded" by her upper side belt at ranges of 25,000 yds or so. If you are going to assume that a shell hitting the upper deck would be deflected downward when penetrating that deck, you have to also assume the upper side belt would deflect shells into a flatter trajectory, making penetration of the lower deck very problematic.

The downwards deflection by the upper deck is only significant over ranges greater than 25,000yds to 30,000yds. The shorter distance a shell has to travel at higher angles of impact to penetrate the main deck is countered by the shell traveling slower at greater ranges, so the time delay for Bismarck's 15in gun would still detonate the shell before the shell penetrated the main deck even beyond 30,000yds if it wasn't for the effect of the upper deck increasing the angle of impact on the main deck.

Okun comments that the KM 15in AP shell has a comparitively short time delay, and any inaccuracy in the fuse that resulted in a slightly longer time would enable the shell to penetrate Bismarck's deck from much closer. I can't find any precise figures on the time delay of the RN 14"/45 AP shell, but since it seems to be set up for more underwater damage, it seems logical that the time delay would be slightly longer than average, and even if only fractionally longer than the KM 15in it would still be able to penetrate as soon as the angle of impact increased enough to allow it to penetrate the 4.4in effective thickness of the armour above Bismarck's engine room.

[David89]

Of course, is good for the "allied cause" to claim a KGV class was worth the money invested because was able to "just slow down" a German BB.

And how much money and resources were used on the 4 ships of the Bismarck and Scharnhorst classes? That money and those resources could arguably have been better used on smaller raiders and submarines.

[Karl Heidenreich]

David89:

And how much money and resources were used on the 4 ships of the Bismarck and Scharnhorst classes? That money and those resources could arguably have been better used on smaller raiders and submarines.

You´re right. A couple of years ago I, myself, advanced such a proposition in this very forum and (even) calculated more or less how many subs, or Tiger Tanks or Me-109 could have been built with the raw materials of Bismarck, Tirpitz, Schanhorst and Gniesenau. From Bismarck displacement alone we could extract 70 Ocean Going U Boats like the U-47. With only half of them at the time in the North Atlantic the British would have had a much worse time.

Battleships are beautiful and I love them, specially the axis ones like Bismarck or Yamato, but, being sincere, they oulived their master´s need. The new weapons, CVs and Uboats would have been the focus. And in this respect Raeder is to blame in Germany as the Fleet Faction is in Japan. Imagine two more brand new Japanese Fleet Carriers the size Yamato and Musashi (well, two Shinanos) in the Pacific. That (if they have the Air Fleets in order to man the air arm) could have given the operational advantage to the Japanese at Midway. Or those 70 (140 not building Tirpitz along Bismarck) U Boats in the Atlantic.

Battleships were a bad investment. U-Boats were the future...

[lwd]

Looks to me like if you go north of Iceland the total distance from Greenland to Norway is less than 5-600 miles. A CV should be able to do a decent job of checking out everything within say a 200 mile radius weather permiting. Then there is sea ice to consider.

What aircraft were available for that purpose and what was their range? Would that subject the CV to Luftwaffe attack?

Earlier in the thread it was postulated that the British had victorious. I'm not sure what her airgroup looked like but assume she had some bombers that could be used as scouts. Whether or not she's subject to LW attacks depends on how she's used and how hard the Germans are looking. I think if it were me I'd send her up off the Greenland coast about 200 miles with the slow BBs as company. I'd have the fast BBs about 200 miles to the East. With cruisers and perhaps DDs scouting both East and West of the fast BBs. I'm not an expert however in British search doctrine.

[Bgile]

Generally speaking, you can't operate carriers with slow battleships. They have to travel at high speed to launch aircraft, and it can complicate your operation quite a bit if you have ships that are very much slower than the CVs in the formation.

I doubt the Victorious had a 200 mile search capability. Remember, you don't just fly out and back. Normally a search arcraft flies a pie pattern.

From your description, it sounds like you are searching in only one area, concentrating on the area where we hypothesized the Germans are going. I don't think Tovey would do that, because then he runs a risk that the Germans go south of his force.

He split his heavy ships into two groups because he didn't think he could cover the whole area with just one. You seem to be assuming he can. There must be something he knew that we aren't seeing.

I played a game a few years back which tried to simulate the problems surrounding intercepting Bismarck and PoW, and it really isn't all that simple. For one thing, the weather can close in making aircraft almost useless and surface visibility very low.

[dunmunro]

Of course some of the FAA Swordfish were equipped with ASV radar, and were nominally, all weather, day/night strike bombers.

[lwd]

Just a quick check on Wiki shows that Victorious carried at least 9 Swordfish and their range is listed as 545 miles. 200 out and 200 back leaves 145 which might be pushing it a bit but is not unreasonable. I don't know if that range is with or without a torpedo if it's without then they should easily be good for 200 mile radius search. If you assume they can see for 15 miles either way then around 11 flights are required to cover the half circle in front of her. That means her Swordfish can do a pretty good scan out to about 200 miles.

Just checked and found that she carried 12 Swordfish of 825 squadron. Ref: http://www.fleetairarmarchive.net/Squadrons/825.html. She also carried a squadron of Fulmar's which had an even greater range and were apparently designed with a recon role in mind.

I was assumeing the slow BBs were operating loosely with Victorious. Ie she would stay close enough to them to fall back on them at night and in bad weather so there's not another Glorious episode. If radar equipped ships can scan a 30 nm radius and non radar equipped ones a 20 nm radisu then it doesn't take that many more to establish a pretty good picket line from Norway to Greenland. That's without considering sea ice.

[Bgile]

You can't count on a 30 mi radius with radar or a 20 mile visual radius.

Victorious turns into the wind. Depending on which way she is heading and how long it takes to launch all swordfish will effect search range. They take 2 hours to go 200 miles, right? So a 5 hour mission. How soon are you going to do this again? Are they all equipped with radar in 1941? That's really impressive! If you fall back on the battleships at night you are going to stop your continuous search flights then? Are you going to do this air search every 12 hours? Every 24? Remember aircraft maintenance and pilot fatigue is a factor. How many days are you going to keep this up? How many weeks? You don't know for sure where the Germans are. Maybe they are headed back to Germany.

[lwd]

You can't count on a 30 mi radius with radar or a 20 mile visual radius.

Quite right. I should have said diameter rather than radius.

Victorious turns into the wind. Depending on which way she is heading and how long it takes to launch all swordfish will effect search range. They take 2 hours to go 200 miles, right? So a 5 hour mission. How soon are you going to do this again? Are they all equipped with radar in 1941? That's really impressive! If you fall back on the battleships at night you are going to stop your continuous search flights then? Are you going to do this air search every 12 hours? Every 24? Remember aircraft maintenance and pilot fatigue is a factor. How many days are you going to keep this up? How many weeks? You don't know for sure where the Germans are. Maybe they are headed back to Germany.

Well they've got 2 squadrons that can search and based on what I found out about the Fulmars likely the Swordfish will either not be used or used to fill in the gaps. Weather will be a problem. I don't see them operating at night. Definitely wouldn't take weeks. You can probably sweep from Iceland to the ice pack in less than a week. I assume that the search planes are launched pretty much continuously as they are on solitary missions launch time shouldn't effect range all that much. It's not guaranteed by any means but if the Germans don't head back for Norway it's got a pretty good chance of turning them up. If you can engage them with the fast BBs then the slow BBs and Victorius can get a shot at anything that's slowed down significantly and even if not slowed down may intercept the Germans if they continue their mission.

[Bgile]

You can't launch continuously because the carrier has to head into the wind continuously then and god knows where you end up, with the old BB's many miles astern.

[lwd]

Continuously in launch a few planes then an hour or so later launch a few more. It's not like your trying to launch a big strike at any one point in time. Also without the torpedos did the British CVs really have to turn into the wind to launch a Swordfish?