Diameter of the extendable boom in the nose of Bismarck

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

Moderator: Bill Jurens

User avatar
tommy303
Senior Member
Posts: 1528
Joined: Mon Oct 18, 2004 4:19 pm
Location: Arizona
Contact:

Post by tommy303 »

yes that would be it. It extended downwards at approximately 45 degrees and seems to have been a feature in Bismarck, Hipper, and Scharnhorst classes. as well as the light cruisers except for Emden. Schmalenbach's Kreuzer Prinz Eugen has a nice photo of the installation hers, while in drydock for repairs following the collision with Leipzig (plate 54). I have no knowledge if it was fitting also in the Panzerschiffe.

trf

Their shoulders held the sky suspended;
They stood and Earth's foundations stay;
What God abandoned these defended;
And saved the sum of things for pay.
User avatar
Ulrich Rudofsky
Contributor & Translator
Posts: 844
Joined: Sat Oct 16, 2004 9:16 pm
Location: State of New York

Post by Ulrich Rudofsky »

I have looked at the Blohm & Voss 1:100 yard plans of Tirpitz. The Breyer plans in the Baron's book also show this structure at the extreme bottom of the bow. It is called 'Bugschutzanlage'. It does not seem to have anything to do with mine protection. On the 1:100 plan it is a tube, rod,or piston 5 mm diameter and 100 mm in length that angles upward at about 30 deg. and is connected to another tube or rod 2.5 mm diameter and 115 mm long which rises perpendicular up to the deck an has a funnel-like opening on deck. Near the front of the lower tube or rod is what appears to be a small electric motor and somesort of lever arm or sensor arm connected to the tube. It just does not look to me like a part of minesweeping setup. That boom whould have to be above the surface. Could it be a depth sensor or hydraulic fender in shallow water like the canal?
Ulrich
User avatar
José M. Rico
Administrator
Posts: 1008
Joined: Sat Oct 16, 2004 10:23 am
Location: Madrid, Spain
Contact:

Post by José M. Rico »

tommy303 wrote:The bowspirite referred to is actually an extendable boom which is underwater (Ausfahreinrichtung für Stenge Bugschutzgerät), and it appears in drawings of Bismarck in von Müllenheim-Rechbergs book. It is also in plans of Scharnhorst and Hipper Classes. It is a boom which can be extended from a tube or channel in the bow and angles down at about 45 degrees. How it was rigged with cables and such for towing paravanes is something of a mystery to me, although it looks as though the cables might have been extended with the mast or boom.
Ausfahreinrichtung für Stenge Bugschutzgerät

Image
User avatar
José M. Rico
Administrator
Posts: 1008
Joined: Sat Oct 16, 2004 10:23 am
Location: Madrid, Spain
Contact:

Post by José M. Rico »

Here are a couple of photos:

Image
Bismarck with the straight stem during her launching on 14 February 1939.

Image
Bismarck with the new "Atlantic" bow inside floating dry dock No. V-VI in Hamburg, June-July 1940.
User avatar
Ulrich Rudofsky
Contributor & Translator
Posts: 844
Joined: Sat Oct 16, 2004 9:16 pm
Location: State of New York

Post by Ulrich Rudofsky »

Those are exactly what I am refering to. I just don't think it has anything to do with mineweeping. It is a sort of hydraulic fender. A sweep boom would have to be above and level with the surface and much longer. Besides, most sweeping was done with a rubber bow protector and the vanes extended from the sides of the ship or even from the stern. I am still not sure what those paravanes on the Bismarck really are used for.
Ulrich
User avatar
tommy303
Senior Member
Posts: 1528
Joined: Mon Oct 18, 2004 4:19 pm
Location: Arizona
Contact:

Post by tommy303 »

Garzke & Dulin call it a paravane tube and list it in the minesweeping department on the detail plans of Bismarck in their volume on Axis battleships.

trf

Their shoulders held the sky suspended;
They stood and Earth's foundations stay;
What God abandoned these defended;
And saved the sum of things for pay.
User avatar
tommy303
Senior Member
Posts: 1528
Joined: Mon Oct 18, 2004 4:19 pm
Location: Arizona
Contact:

Post by tommy303 »

It would seem that to have a bow boom above the water would not work as effectively as having the spar underwater and angled downwards. To protect the bow, the lines from the spar would need to run deeper than the ship in order to foul the mooring cables of contact mines and push them outwards and back towards the otters which would then cut the cables. If the lines did not start below the level of the bow, they could miss snagging the mine's cable and allow it to hit. See also S 85, Schmalenbach, Kreuzer Prinz Eugen.

"Die vorderen Haltepunkte der Sägeleinen werden durch Öffnungen in der Bugschutzpier gebildet. Diese Spier ist etwa 9 m lang. Sie liegt mittschiffs und is gegen den Horizont ca 35 grad nach vor und 2,4 m unter der Unterkante des Vorstevens. Die erwähnten Scheren werden von fischänlichen "Ottern" getragen, die am äußeren, hinteren Ende der Sägeleine so befestigt sind, daß erfaßte Ankertaue von der Leine in die Schere geführt werden."

trf.

Their shoulders held the sky suspended;
They stood and Earth's foundations stay;
What God abandoned these defended;
And saved the sum of things for pay.
User avatar
Ulrich Rudofsky
Contributor & Translator
Posts: 844
Joined: Sat Oct 16, 2004 9:16 pm
Location: State of New York

Post by Ulrich Rudofsky »

I stand corrected. That is the right answer. It served for anchored mines at far below the surface. The people at http://www.schlachtschiff.com just told me that there is a difference between actual minesweeping and pushing away of anchor mines with the paravanes in self-defense. They say that 2 otters were cabled to the bowsprit and 2 boomed out amidships, and 2 were kept as reserves. So pointing the bowsprit 35 deg. down from the lowest point of the ship suddenly makes sense to me. I appologize for adding to the confusion........... :silenced:
Ulrich
User avatar
BB_57
Supporter
Posts: 13
Joined: Sat Jun 04, 2005 4:07 am
Location: SoCal USA

Great information Gentleman!

Post by BB_57 »

I would have never figured this one out alone as completely as all of you have. Thanks for the information! I find it fascinating!!! :clap:
iankw
Member
Posts: 196
Joined: Wed Nov 10, 2004 11:41 pm
Location: Rotherham, England

Post by iankw »

OK, having solved one enigma let's move on.

Why does it need to go up to the deck?

Am I missing something obvious here?
User avatar
BB_57
Supporter
Posts: 13
Joined: Sat Jun 04, 2005 4:07 am
Location: SoCal USA

Bulkheads!

Post by BB_57 »

If I'm understanding your question correctly then could it have been to keep the pole from extending into other bulkheads to minimize the risk of flooding issues.
User avatar
Ulrich Rudofsky
Contributor & Translator
Posts: 844
Joined: Sat Oct 16, 2004 9:16 pm
Location: State of New York

Post by Ulrich Rudofsky »

Josef @ http://www.schlachtschiff.com explains it all!

Das habe ich aber auch geschrieben, wie das funktionierte: Schäftseil durch den Rohrkanal abgelassen, Kopf des Schäftseils mit dünnen Leinen ein- und an Oberdeck geholt, Sägeleinen angeschlagen am Kopf des Schäftseils, Ottern am anderen Ende, zu Wasser gelassen, Spiere ausgefahren und Übung macht den Meister!

I have already written about that too [at schlachtschiff.com] and how it functioned: a line was passed down the shaft; head first, the shaft line was lowered with a thin line and brought back to the upper deck, the cutting lines were attached to the head of the shaft line, and the otters on the other end, and lowered into the water and the sprit was run out and practice makes perfect!

I still have a little problem with that routine, but somehow the line went down the tube, was retrieved and brought back on deck........ :? :?

I also agree that the tube protected from entry of water into the ship. It also seems to be a very vulnerable contraption. I wonder what happend to this thing when the Bismarck took a hit in th bow. A leak down there would be hard to deal with.
Ulrich
User avatar
tommy303
Senior Member
Posts: 1528
Joined: Mon Oct 18, 2004 4:19 pm
Location: Arizona
Contact:

Post by tommy303 »

I have a problem visualizing exactly how that was done myself, Ulrich. I would think it to be most difficult to retrieve the lines without some sort of float arrangement---otherwise, how to haul the thin line back topside to attach the Otters to the cutting line. I frankly dont see how this could be done unless the ship were stopped or barely making steerageway. I think we still have a few details to iron out.


trf

Their shoulders held the sky suspended;
They stood and Earth's foundations stay;
What God abandoned these defended;
And saved the sum of things for pay.
User avatar
tommy303
Senior Member
Posts: 1528
Joined: Mon Oct 18, 2004 4:19 pm
Location: Arizona
Contact:

Post by tommy303 »

I have noticed that the Vittorio class, KGVs, Richilieu, and Dunquerque classes all had a forefoot plate with holes through it, and several shots of the KGV and Vittorios show them steaming with lines running up to the forecastle from the bow's forefoot. Presumably this was also a pravane attachment point. After a bit of a search I found a foto of Hipper with some very thin lines rigged in simialr fashion. They are quite thin but look very much like they run down to the boom (see German Cruisers by Whitley, p. 102). Presumably the ship might have steamed with those rigged when in shallow waters in case it became necessary to rig the otters. Otherwise, I dont see how it could be done underway.

trf

Their shoulders held the sky suspended;
They stood and Earth's foundations stay;
What God abandoned these defended;
And saved the sum of things for pay.
User avatar
Ulrich Rudofsky
Contributor & Translator
Posts: 844
Joined: Sat Oct 16, 2004 9:16 pm
Location: State of New York

Post by Ulrich Rudofsky »

What you are suggesting is that Bismarck may have had this contraption rigged before departing Gotenhafen or Norway, since they knew for certain that the Denmark Strait was mined. That may have exposed the bow section to serious problems when it was hit.
Ulrich
Post Reply