Head on Collision

Georges Guay

Georges Guay

Member
As far as a rotating compass card, what Hichen saw was a rotating card caused by the ship along with him turning to port. The description used the ship as the frame of reference., just like Murdoch and the lookouts saw an iceberg approaching them, when it was them approaching an iceberg. :)

Or you could have said that the berg altered course to port toward Titanic starboard side and while the stern was veering to port after the allision, the pole star moved to westward in front of Titanic! :)

Samuel, we are talking about a brand new liner outfitted with the very best British main and standard maritime compasses. These compasses were fully adjusted, their bowl completely filled by the exact anti-damping and antifreeze liquid of specific density, their cards made significantly smaller in diameter than the bowl to minimize swirl error, the card oscillation could not have happened since the vessel was sailing in a sea as flat as a mirror, heeling deviation only occur at large angle, oscillation effects are maximum on north and south headings and so on. We are thus very far from a piper magnetic compass.

Nevertheless, when a vessel is turn for maximum rate of turn and steady with a sudden hard over counter wheel, the inertia of the card along with the insidious liquid movement, will make the compass card to overshoot the terrestrial magnetic field horizontal and directional component. But swiftly afterward, the magnetic moment created will force back the card to line up again. Samuel, I own 2 commercial vessel magnetic compasses. I have made a dozen turns with one on them this morning, some at unattainable rate of turn for a vessel, to port and to starboard, on a north/south and east/west initial heading. When the card was stable and lined up to the magnetic field, I turned the compass 45° to 90° to a desire appoint and repeated the experience. On any initial steady heading followed by the swing the compass, the card remained entirely fix whereas the lubber’s line was unambiguously seen veering or backing in the proper direction. When you stop swinging, the compass card keeps swinging to angles proportional of the rate of turn. If you swing slow, the compass card overshoots to a few insignificant degrees away from the desired steady lubber’s line, and then settles back. But if you swing very rapidly, the compass card overshoots the desire new steady heading to about twice that few degrees. Really nothing to be concerned about; just imagine what would have been the consequences in channels if it would not have been the case!

Therefore, when Hichens confirmed the wheel hard over, as a capable quartermaster he was watching the lubber’s line backing unmistakably to port, certainly not the compass card veering to starboard! The only thing he could then do if trained for, is to call every point that were decreasing by, which was apparently not the case....
 

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Samuel Halpern

Samuel Halpern

Member
Georges, if you turn a compass by hand the lubber line will of course turn and the compass card will try to remain pointed in a fixed direction. But in the case of a helmsman steering a ship, it is the ship that is turning carrying the helmsman and the compass in front of him with it. To the helmsman the lubber line is not moving but the compass card is rotating. But you know all that, and just trying to have a playful discussion.
By the way, unlike a ship's compass,the magnetic compass in a small Piper or Cessna aircraft is not suspended by gimbals. It consists of an inverted bowl with a magnetized bar attached. The bowl is balanced on a low friction pin, and the bowl and pin assembly is enclosed in a case filled with kerosene.
 
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Mark Baber

Staff member
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Moderator's note: Two messages containing only personalized commentary about other participants in this discussion have been removed.
 
Steven Christian

Steven Christian

Member
Sort of off topic again today but did degaussing a ship affect the compass accuracy? Do they even degauss anymore? Curious because I had a good friend where I worked who spent his enlistment degaussing warships at Pearl.
 
Jim Currie

Jim Currie

Senior Member
Hello Steven.

The first new-built Merchant vessel I served on after WW2 was the SS Ormsary in 1953. She was fitted with a set of degausing wires all around her uppermost continuous deck. Most older ships had them because even at that time, ships were still being sunk by magnetic mines in the North Sea.
However, by that time, ships did not use the Standard Magnetic Compass because they nearly all had gyro compasses.
 
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Steven Christian

Steven Christian

Member
Try turning an airplane with an inoperative direction gyro by following the mag compass. You can experience lead or lag, depending on the planes initial heading. Multiple forces at work there.
Yes you got that right. When I was working on my instrument rating shooting VOR approaches and practicing different scenario's rolling in/out early or late to catch the lead lag was a lot easier on paper than doing it for real. Especially when monitoring different instruments at once with the blinders on. But it was interesting and fun if not frustrating at times.
 
Steven Christian

Steven Christian

Member
Hello Steven.

The first new-built Merchant vessel I served on after WW2 was the SS Ormsary in 1953. She was fitted with a set of degausing wires all around her uppermost continuous deck. Most older ships had them because even at that time, ships were still being sunk by magnetic mines in the North Sea.
However, by that time, ships did not use the Standard Magnetic Compass because they nearly all had gyro compasses.
Thanks for the reply Jim. I looked into it a little more. Seems modern ships have degaussing coils built in them located at different parts of the ship. And some use different methods also built in. I remember my friend telling me they had to string cables around the ships. He said it was mostly mine sweepers up to destroyers. Must have been labor intensive. I built mines when I was in the navy but they were a different kind. We had what they called destructors (MK 40's if I remember right). Basically it was a 2000lb general purpose bomb with a special fuse that was a magnetic field detector. I dont believe they use them any more but a lot were used during Nam. You could use them on land or in the water. I looked at a website that said after the war a whole lot of mine sweepers were sunk or damaged trying to clean up the left overs. When the navy quit looking it said there were still over 13,000 mines not yet accounted for...:oops:
 
Cam Houseman

Cam Houseman

Member
FWIW, this is Edward Wilding's take on the possible consequences of a head on collision with the berg:

20269. You mean it did not strike a fair blow? - If she struck it a fair blow I think we should have heard a great deal more about the severity of it, and probably the ship would have come into harbour if she had struck it a fair blow, instead of going to the bottom.

20270. You think that? - I am quite sure of it.

20271. (The Commissioner.) I am rather interested about that. Do you mean to say that if this ship had driven on to the iceberg stem on she would have been saved? - I am quite sure she would, my Lord. I am afraid she would have killed every firemen down in the firemen's quarters, but I feel sure the ship would have come in.

20272. And the passengers would not have been lost? - The passengers would have come in.

20273. Then do you think it was an error of judgment - I do not by any means say it was a negligent act at all - to starboard the helm? - It is very difficult to pass judgment on what would go through an Officer's mind, my Lord.

20274. An error of judgment and negligence are two different things altogether. A man may make a mistake and be very far from being negligent? - Yes.

20275. Do you think that if the helm had not been starboarded there would have been a chance of the ship being saved? - I believe the ship would have been saved, and I am strengthened in that belief by the case which your Lordship will remember where one large North Atlantic steamer, some 34 years ago, did go stem on into an iceberg and did come into port, and she was going fast? - I am old enough to remember that case, but I am afraid my memory is not good enough.

Mr. Laing: The "Arizona" - I remember it.

The Witness: The "Arizona," my Lord.

20276. (Mr. Rowlatt.) You said it would have killed all the firemen? - I am afraid she would have crumpled up in stopping herself. The momentum of the ship would have crushed in the bows for 80 or perhaps 100 feet.

20277. You mean the firemen in their quarters? - Yes, down below. We know two watches were down there.

20278. Do you mean at the boilers? - Oh, no, they would scarcely have felt the shock.

The Commissioner: Any person, fireman or anybody else, who happened to be in that 100 feet, would probably never have been seen again?

20279. (Mr. Rowlatt.) The third class passengers are there too, I think, some of them? - I do not think there are any third class passengers forward of the second bulkhead, and I believe she would have stopped before the second bulkhead was damaged. It is entirely crew there, and almost entirely firemen - firemen, trimmers, and greasers.

20280. Your opinion is that the ship would have suffered that crushing in in the first two compartments, but that the shock would not have shattered or loosened the rivets in any other part of the ship? - Not sufficiently. As it would take a considerable length, 80 or 100 feet to bring up, it is not a shock, it is a pressure that lasts three or four seconds, five seconds perhaps, and whilst it is a big pressure it is not in the nature of a sharp blow.

20281. (The Commissioner.) It would, I suppose, have shot everybody in the ship out of their berths? - I very much doubt it, my Lord.

20282. At 22 1/2 knots an hour, and being pulled up quite suddenly? - Not quite suddenly, my Lord. 100 feet will pull up a motor car going 22 miles an hour without shooting you out of the front.

20283. (Mr. Rowlatt.) What you mean is that the ship would have telescoped herself? - Yes, up against the iceberg.

20284. And stopped when she telescoped enough? - Yes, that is what happened in the "Arizona."

Edward Wilding's testimony may be accessed by way of The Titanic Inquiry Project
But if most of the Firemen, greasers, trimmers, and engineers had been killed in the impact, would they be able to get home? They would need people to shovel coal, trim the ship to prevent the ship from listing to port or starboard, or capsizing. They would need enough Engineers and electricians to keep the power going, and find a speed for Titanic to be safe enough to make it back to Southampton or Halifax. Or, to keep the wireless going so Titanic can be towed, like when it was reported that Titanic was being towed by the Parisian. Would they be able to close the watertight doors? Britannic's frame was warped by the mind explosion. What if that happened? Would passengers have to stand in for the lost crew? And, how would they get Titanic off the iceberg without doing more damage? Maybe Titanic ran into and over the iceberg, smashing through the iceberg, leaving the propellers partially or fully out of the water?
 
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meyre76

Member
I was just arguing with one of my buddies about this. He claims that it most definitely would not have sunk if it hit directly head on. I kind of understand his side considering there wouldn't have been multiple breaches along the side, but to me it just seems crazy that the front of the ship could have withstood that kind of force given the sheer mass of the ship (the iceberg as well) and the velocity it would have been traveling at when impact occurred. I am hoping there may be some structural engineers lurking around that could shed some light on this.
 
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