Torpedoes on Bismarck???

Discussions about the history of the ship, technical details, etc.

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tommy303
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Post by tommy303 » Wed Mar 22, 2006 6:18 pm

The recommendation for torpedos aboard KM capital ships was made by Fleet Commander Luetjens following his return from the raiding cruise with Scharnhorst and Gneisenau. His recommendation was that the torpedo was more efficient than main, secondary or tertiary armament in sinking a merchant ship quickly particularly in a situation where there were multiple targets, as in a convoy action. In such a scenario, the time it might take to sink a merchant ship, particularly a tanker, with gunfire, could allow others to escape if weather and visibility were poor. A torpedo was more certain in those circumstances, and while the torpedo itself might be more expensive, gunfire is not just cost of ammunition, but also wear and tear on the guns themselves which will eventually have to be replaced or relined.

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Post by marcelo_malara » Wed Mar 22, 2006 6:25 pm

ok tommy, your explanation makes sense. But lets go deeper, other than merchant raiding, is there any need for torpedoes on a battleship?

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Post by tommy303 » Wed Mar 22, 2006 11:40 pm

None whatsoever. They are much more a liability than an asset in my opinion, which is why most 1930s battleships entered service without them In the traditional role of the battleship, there would have been few opportunities to use them.

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Ulrich Rudofsky
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Post by Ulrich Rudofsky » Thu Mar 23, 2006 2:13 am

.....however, for some obscure reason Bismarck had depth charges (WABO) onboard and was equipped with mine-sweeping paravane equipment and mine-detonating charges. Why would any battleship need those things?
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Bismarck's Accessories

Post by wadinga » Thu Mar 23, 2006 1:11 pm

Ulrich,
Although a fanciful theory suggests depth charges could be used to mislead enemy gunnery spotters, (Antonio! -maybe once in a blue moon) they were actually held for scare tactics on an attacking sub or even killing sabotaging divers. PG's charges disappear from the stern during the Denmark Strait action, but then no-one would want hundreds of pounds of high explosive sitting in tin cans on the upper deck during a battle, so I believe they would have been jettisoned as soon as possible. This might be possible by remote control, but more likely some lucky sailor had to run out there and cut the lashings adrift.

The paravanes which most major warships deployed when steaming in water depths suitable for moored mines were purely a self defence feature. They had to be brought aboard once speed was increased as speed would tear them adrift. Active minefield clearance was left to more expendable vessels and crews.

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marcelo_malara
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Post by marcelo_malara » Thu Mar 23, 2006 2:27 pm

How exactly does a paravane work? It seems that you can cut loose a moored mine AFTER the ship has passed, so what is exactly the function on a battleship?

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Post by Ulrich Rudofsky » Thu Mar 23, 2006 2:38 pm

I agree fully with you on that with you. Another odd item aboard Bismarck was a load of minesweeping equipment ammo [Minenräumgerät-Munition]
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Post by Ulrich Rudofsky » Thu Mar 23, 2006 2:53 pm

I will post a diagram in a few minutes, when I find it.
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Post by wadinga » Thu Mar 23, 2006 3:04 pm

Marcelo,

A chain or heavy wire takes a towpoint for the paravanes down the ship's bow to the forefoot and the vane flies through the water, with its tow-wire going back from the bow at maybe 30-35 deg to the centreline. The tow wire is let out maybe 40-50m, so the paravanes fly parallel to the ship, one each side. If a mine's mooring wire strikes the tow wire it is shouldered aside by the tow-wire, pushing the mooring wire and mine further away from the ship, until it hits a cutting blade close to the paravane. With the wire cut the buoyant mine pops up to the surface, and if no sharpshooter can hit a horn, their rifle shots hole the casing and the mine harmlessly sinks to the bottom.

However, deploying and retrieving paravanes requires a fair bit of manual handling, and tow loads mean they must be retrieved to allow the vessel to go more than slowish cruising speeds. Heavy weather makes them difficult to handle, and the vessel must limit violent manouevring whilst they are deployed. Of course they offer no protection against magnetic or acoustic mines.

All navies used them during World War II. The dedicated minesweeping vessels would deploy a single paravane, and sail in en echelon formation, each vessel protected by the paravane of the one ahead. In theory. In reality, brave men like my wife's grandfather risked obliteration day in day out as unsung heroes as loose mines might hit the following vessels, or slight formation errors let unseen killers through.

Bis and Tirpitz had a fancy retractable mine spar- "Vorsprung Durch Teknik" to attach the chains which allowed the tow wire to be attached on deck then passed down the prow to the forefoot.

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Post by miro777 » Thu Mar 23, 2006 3:08 pm

hey
that there were WABOs on Bismarck is very interesting!!

but let's go back to my initial question.

Why did the HMS Rodney have TTs?

the rodney certainly wouldn't need it to sink enemy merchants...
so whats the use?

Anyone has an answer to that?
Die See ruft....

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Post by marcelo_malara » Thu Mar 23, 2006 3:13 pm

Wadinga, some doubts about your explanation. Why doesn´t the paravanes come close to the ship´s sides?, I mean how does they keep at a 30 degreee angle? What happens with a mine exactly dead ahead?

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Ulrich Rudofsky
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Post by Ulrich Rudofsky » Thu Mar 23, 2006 3:14 pm

http://www.kbismarck.com/oequipment.html

http://i18.photobucket.com/albums/b138/ ... tungen.jpg [property of Josef Kaiser, the author of two fine reccent books on Bismarck]

http://i18.photobucket.com/albums/b138/ ... gerat1.jpg

Schematic Representation of a Torpedo (Longitudinal Section)
(Length ca. 7 m, diameter 55 cm)

Sprengladung = explosive charge
Gefechtspistole = warhead detonator
Gefechtskopf = warhead
Führungsstück = guide piece
Luftkessel = air tank
Antriebsmaschine = propulsion engine
Tiefensteuerapparat = depth control mechanism
Geradlaufapparat = Straight-ahead drive control
Hinterteil des Antriebs- u. Steuermechanismus = Aft section of the propulsion and steering mechanism
Tiefenruder = depth control rudder fin
Seitenruder = lateral rudder (yaw)
Propeller = propellers
Schwanzstück = tail section


The Otter Equipment (mine protection equipment)

Mode of Operation
A mine is snagged and slides along the sweeping line to the starboard otter which will cut the anchorline. The mine will then rise to the surface of the water and can then be rendered harmless.

Otter in Schwimmlage von der Seite gesehen = Otter in swimming attitude, side view
Schlepprahmen = towing frame
Otter in Schwimmlage von oben gesehen = Otter in swimming attitude, bird’s-eye view
Schleppleine = tow line
Reißkeilschneider = ripping wedge cable cutter
Ruder = rudder
Schwimmer = floatation tanks
Schlepprahmen = towing frame

Der Reißschneider schneidet Minenankertaue bis etwa 38 mm Umfang = the ripping cutter cuts mine anchor cables of approximately 38 mm circumference.
Ulrich

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marcelo_malara
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Post by marcelo_malara » Thu Mar 23, 2006 3:23 pm

Wonderfull info Ulrich!!!
Thank you very much for the posting!!!

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Ulrich Rudofsky
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Post by Ulrich Rudofsky » Thu Mar 23, 2006 3:29 pm

What happens with a mine exactly dead ahead?
Your luck has run out.......(I don't know for sure, but I think there were massive rubber bow protectors in use on minesweepers.)
Ulrich

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Post by wadinga » Thu Mar 23, 2006 3:57 pm

Marcelo,
On Ulrich's drawing you may be able to see the tow point on the paravane is offset from the nose, so just like a kite in air, lift is created when the paravane is dragged through the water. Because water is 800 times denser than air, a lot of power is produced even at quite slow speeds. When the drag on the body and it's tow-wire balances the lift generated, the paravane achieves a stable position relative to the ship. The buoyant body keeps it close to the surface.

In a minesweeping formation, the lead ship aims to sail to one side clear of the mined area. Being lucky is very, very important.

I don't know about rubber bows but Sperrbrechers were German "mine Bumpers" with reinforced bows filled with extra buoyancy, to act as sacrificial leaders to a formation. Old, less useful merchant ships were detailed off for this, deployed their paravanes and hoped for the best.

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