All myths solved

[yellowtail3]

Karl is actually one of our more senior members and one of the few that has donated anything to the site, besides information of course.

Oh.

And I hate to admit it... but yes you have trolled... posting nonstop.

well, perhaps I misunderstood what a troll is. What is considered to be an appropriate interval between posts, that will avoid earning the sobriquet of troll?

Karl is welcome to address the substance of my post(s) that induced him to call me an idiot and a troll. My experience is that some peeps - esp. the thin-skinned types? - quickly resort to dismissive nastiness, when they don't have good answers or when their prejudices are strongly challenged. Is that what has happened, here?

regards,
The Troll (?)

[Bgile]

Apparently, Karl, you're easy to provoke. But you're being unkind, Karl, along with unfair and inaccurate - I've not trolled.

Karl is actually one of our more senior members and one of the few that has donated anything to the site, besides information of course.

And I hate to admit it... but yes you have trolled... posting nonstop.

Huh? Posting nonstop is trolling? What's going on here?

[yellowtail3]

Huh? Posting nonstop is trolling? What's going on here?

Apparently I've offended Karl. Perhaps I should have asked permission before posting in this forum. Is there an 'introductions' thread, where one can get permission - from Karl? - to participate in Naval History Forums?

[Legend]

Troll- One who is overly active online. Similar to a spammer. I said trolling in the context of "acting like a troll"

I merely mean to show that a certain amount of respect is due to some of the senior members. Mr. Hiedenreich, BGile, and lwd being some of the more elderly and educated among them.

No offense to anyone,
Matthew

[Mostlyharmless]

About the rudder arragement: Which WWII (or contemporary BBs) had a rudder arragement that would have prevented a similar situation if hit by a torpedo as Bismarck was?

North Carolina, Washington, Massachusetts, Indiana, South Dakota, Alabama, Iowa, Wisconsin, Missouri, and New Jersey.

As far as I can see, the South Dakotas have a more vulnerable arrangement than say Yamato and all the American BBs can be reduced to steering with engines by a single hit. However, Iowa or North Carolina can steer with engines better than Bismarck and the outer shafts are well separated from the rudders. We know that the KGVs were equally vulnerable as Bismarck from the case of PoW. However, Vittorio Veneto actually has two well separated sets of rudders and survived a hit in that region at Matapan. Thus VW is my answer.

[yellowtail3]

excellent point, Mostly. And those Italian ships were pretty. Some more training, and three or four months in Norfolk - for new directors, shells, and 5"/38s? - and she's have been a first-class, short-ranged battleship. To your point... plenty of rudders, there!

[yellowtail3]

I think this is Vittorio Veneto after taking a torpedo up the (stern) - note floatplane askew. It was at an Italian site...

[Bill Jurens]

The discussion here seems to revolve primarily around the relative resistance to torpedo damage of American vs German battleships, or -- more precisely -- American battleships vs Bismarck, particularly in the area of the rudders.

In general, examination of the ships drawings, would indicate that the steering gear of the American ships was significantly better protected against ballistic attack, and probably somewhat more resistant to underwater attack, i.e. damage from explosions near the bottom. In the case of a torpedo hitting in the 'same place' as on Bismarck, the amount of flooding would probably have been similar, i.e. it is likely that the steering gear compartment(s) would have probably flooded in either case.

The torpedo that struck Bismarck struck on the rudder itself, and as the rudders per se on both Bismark and the American ships are similarly protected -- i.e. not protected at all -- the results on all ships under discussion would probably also have been similar. Whether one ship or another retained more maneuverability afterwards would probably have depended more upon the nuances of the actual explosion itself, e.g. the angular position of the rudders when struck and the exact location where they were struck, than on any individual differences in design.

All ships would have most likely ended up with flooded steering gear compartments, and both rudders -- for one reason or another -- out of commission. It would seem probable that all ships would have lost use of the shaft immediately adjacent to the blast, rendering Bismarck with two workable propellers and one of the American battleships with three. It is unlikely that this would have made any signficant difference is subsequent maneuverability. In practical terms, regardless of differences in geometry, the ability to steer by engines alone at any significant forward speed with jammed and distorted trailing rudders, is usually essentially zero.

Bill Jurens

[yellowtail3]

thanks for that post, Bill.

Here's something interesting, directly relevant to your post. I think this supports the position - my position - that the four-shaft arrangement of US BBs was substantially superior to Bismarck's convergent three-shaft design, in terms of maneuverability and especially damage resistance. This may not be new info to the folks on this board, but it is interesting and relevant ~

The Intrepid (CV-11) was hit on her rudder post by a Japanese air-launched torpedo on Feb of 1944. Don't know which torpedo, but probably had a larger warhead than that carried by Swordfish that crippled Bismarck. Anyhow... this torp detonated under the fantail, vented into the hull, ruined steering gear, jammed (single) rudder 6+ degrees left and distorted it... leaving all four shafts undamaged. The carrier was not left DIW, but retained a good deal of speed and some ability to maintain desired course at speed.

1. At 0011, 17 February 1944, Zone plus 12 Time, the U.S.S. INTREPID was hit, by an aircraft torpedo, just forward of the rudder post. The night was clear but dark. The resultant damage presented various problems which may be of interest in handling similar damage in the future.

NARRATIVE

2. At the time the torpedo hit the INTREPID was in a left turn using 15° left rudder and at 25 knots. The detonation ruptured the bottom of the steering engine ram room and motor room, immediately flooded these two compartments and jammed the rudder. Propellers and engines sustained no damage. The crosshead and the rams of the steering gear were completely wrecked. The rudder was severely distorted and the fin which fills in over the counterbalance of the rudder was blown off, (See enclosures). The detonation opened a hole in the starboard side which extended from near the keel to above the fourth deck. The fourth deck in way of the explosion was completely missing. The third deck in the Chief Petty Officers' country was pushed up to the overhead of the second deck, and missiles penetrated the hangar deck. Complete details of the damage are contained in the Action Report. The net result of this damage insofar as ship control was concerned was to create the permanent effect of approximately 6½° left rudder. The INTREPID had the advantage of having made the standardization trials for the CV-9 class. One of the tests conducted was to lock an outboard shaft on one side, go ahead full power on the two shafts on the other side and determine the rudder angle necessary to maintain a steady course. This rudder angle during the trial proved to be approximately 6½°. After the torpedo hit it was found that the combination needed to maintain a steady course approximated the condition found during trials.

read report & see photos here http://tinyurl.com/yz2mzjs ...to see how they navigated after being hit.

Had Bismarck's stern been as well-designed, she might have been better off May 26/27 - Intrepid was able to do 20+ knots with a modest degree of control after taking a torpedo under similar circumstances as Bismarck. Intrepid's crew had more time to deal with the damage, and wasn't under quite the same pressure as Bismarcks, but... they managed.

[tommy303]

I wouldn't necessarily say Bismarck's stern was more poorly designed than Intrepid's; merely it was designed differently with different criteria. The designers cut down on deadwood--skegs, rudder support stocks, etc.--in an effort to reduce drag and improve maneuverability. In addition, the damage was such that the rudders were jammed at a significantly greater amount of deflection than the six or so degrees suffered by Intrepid. According to Baron von Muellenheim-Rechberg, the rudder indicator showed 12*. Had Interpid been subject to heavy seas and adverse winds, and had her rudder been jammed at a greater degree of deflection she may well not have had control to any significant degree either.

[dunmunro]

Just a quick note to point out that PoW's rudder was not damaged, and given time the crew would have restored it's function.

[Bgile]

Yellowtail,

Thanks for that post. I was aware that a US carrier had received that type of damage, but hadn't seen a photo until now.

[Terje Langoy]

Not to question superiority of design, American vs German, but I did make a post on this a while ago where I made my stand that any rudder, regardless of stern construction, always will be vulnerable to a direct hit as long as you use the traditional blade to steer with. It will always be exposed. Should one attempt to determine superiority the criteria would perhaps be protection of the steering gear itself. (Rudder stock and engine plus access)

One could try to determine the better screw arrangement, three vs four, to evaluate steering quality of screws alone but keep in mind that this in turn is related to external conditions. The fact that Bismarck could not steer by her screws are due to several factors, not all of them contributed to the nature of design. Had Bismarck lost her entire rudder instead of having it jammed she would not suffer counterproductive effects, this being the unfortunate `blocking´ of prop thrust and drag effect upon the keel itself. A jammed rudder will counter-steer whenever the keel attempt to steer in any direction but the fixed rudder position. This works very much like in a car where the front wheels, if toe in-toe out is incorrect set, will cause the car to constantly seek away from steering straight forward.

That said, Bismarck was also severely influenced by external factors - sea state and wind direction. This was not a calm day in the Baltic with a cool breeze and sea flat as a floor, Bismarck was trapped by huge Atlantic waves and strong winds, forcing the ship in directions not desirable. It is not hard to imagine that the screws, being two, three or four, would have to perform miracles regardless of arrangement. To steer they would have to constantly monitor and predict the ship´s movement, distribute proper amount of thrust and power and finally apply this to the right screw at the right time - this while also compensating for a jammed rudder plus shifting wind and seas. I imagine it most likely impossible for any ship suffering this kind of damage and conditions to steer by screws, let alone the fact that the ship still must be able to generate enough forward thrust to successfully evade her pursuers as well.

The only thing that could save Bismarck would be a tug accompanied by an armada of escorts for protection - or a set of bow thrusters. It is in my opinion ridiculous to use this episode as evidence that Bismarck´s stern design was flawed...

[yellowtail3]

It is in my opinion ridiculous to use this episode as evidence that Bismarck´s stern design was flawed...

ridiculous? that's uncharitable. The circumstances in which the two ships were damaged was very similar. Both hit aft in (nearly) the same place by an air-dropped torp. Intrepid was running 25 knots, 15 degrees left rudder when struck. I think Bismarck had her rudder over a similar amount, same direction, but was running a few knots slower. No doubt about it, though - Intrepid retained substantially more mobility afterward.

Had Bismarck lost her entire rudder instead of having it jammed she would not suffer counterproductive effects, this being the unfortunate `blocking´ of prop thrust and drag effect upon the keel itself.

If you didn't read the linked report, check it out... very interesting. After they got back to Pearl Harbor - no mean feat, that - the rudder was removed with the idea they'd better steer w/screws, if unencumbered with a jammed rudder. It turned out that the ship was even more difficult to control without any rudder, than with a jammed 6 degree rudder. Bismarck may or may not have suffered similarly, but I'll bet she would have been even harder to steer with screws.

read para 4. It must have been a very exciting time to be on the bridge, and very wearing down in main control... and probably entertaining to watch from any nearby destroyers - "stay out of her way!"

It is in my opinion ridiculous to use this episode as evidence that Bismarck´s stern design was flawed...

No, not ridiculous... just an adverse data point.

[José M. Rico]

The Prinz Eugen was hit on the stern by a 21-inch torpedo from the British submarine Trident off Trondheim on February 1942. The rudder was entirely lost (PG had only one) and the stern collapsed. However the three propellers were not affected and the ship managed to reach Trondheim by her own.