how far will a ship roll without capsizing? - Page 6 - PeachParts Mercedes-Benz Forum

chazola · #76 05-12-2011, 01:20 PM

You may well be right about Churchill never travelling on the QM, this is wiki after-all... but I believe the QM was faster than any warship of the time and could easily outrun U-boats, so maybe would be a good choice to travel on if you were PM...

t walgamuth · #77 05-12-2011, 05:20 PM

I would have said he always traveled in military vehicles too. I know Roosevelt did. Battleships or as Hattie said fast cruisers.

MTUpower · #78 05-12-2011, 08:46 PM

As long as the CG (center of gravity) is inboard of the CB (center of buoyancy) then the vessel has a GZ (righting arm) and will return to upright after a roll. If you want to know what the roll of a specific vessel is:
T= .44 x B divided by the square root of the GM.
T= rolling period in seconds.
B= ship's beam
GM= metacentric height

MTUpower · #79 05-12-2011, 08:55 PM

Here's a a few good ones:
You are on a course of 251 pgc and 241 per magnetic compass, when you observe a range in line bearing 192 pgc. The chart indicates that the range is in line on a bearing of 194T. The variation is 16E. What is the deviation of the magnetic compass?

You are underway and intend to make good a course of 040T. You experience a current with a set and drift of 190 T at 1.4 knots, and northwest wind produces a leeway of 3. You adjust your course to compensate for the current and leeway, while maintaining an engine speed of 10 knots. What will be your speed made good over the intended course of 040 T.?

Botnst · #80 05-12-2011, 09:18 PM

Quote:

Originally Posted by dynalow

The 64k question Bob is: Did any DD gun turrets roll out at 52 deg?

I suspect not, but one never knows.

On a small vessel like a destroyer or corvette they don't have turrets, they have mounts. A mount is attached to the deck under it while a turret extends down several decks, perhaps to the keel. When the turret turns the whole aiming system and magazine turn with it. When it fires the recoil gets absorbed by the decks of the whole vessel through which it passes. A gun mount transfers all recoil energy directly to the deck. For a small bore weapon that's acceptable. But for a 16" dia rifle accelerating a half-ton shell down it ... you need a turret.

A turret will fall out of a capsized vessel.

BobK · #81 05-13-2011, 06:58 AM

Dad's ship had 5 inch guns. For awhile his general quarters station was on the ammo level for one of the guns. He stuffed the rounds into the hoist that sent them up to the barrel, the hoist arming them as they made the trip up. One time a live round came down the other side where spent cases were supposed to come down. There he was holding a live round with the timer running! Did the only thing he could think of: he opened the hatch, ran to the rail and pitched it overboard! It was supposed to be impossible for a live round to come back down.
Another station he had was on a 20mm pom-pom gun. he was one of 4 loaders. They would drop four round clips of ammo into the gun. Even as slow aas it fired, all four loaders were busting their butts to keep the thing fed.

t walgamuth · #82 05-13-2011, 07:06 AM

Wow! That is a story! I gotta wonder how much a shell for a five inch gun weighs?

Botnst · #83 05-13-2011, 07:54 AM

Little over 50# for the whole cartridge.

t walgamuth · #84 05-13-2011, 12:58 PM

Hard to believe it is that light. Is it a cartridge like for a rifle?

Hatterasguy · #85 05-13-2011, 01:08 PM

On the 5in? The new ones are self contained, I believe the old had separate powder charges.

http://www.youtube.com/watch?v=QZXpWtBzFSc
I find it hard to imagine one can have any hearing after serving on one of those ships. One little BS blank charge is loud! Hard to imagine all the 5's going, Bofars, and probably return fire screaming around/impacting and metal chunks screaming through the air.

http://www.youtube.com/watch?v=4-5fCigJK5E

dlevitt · #86 05-13-2011, 01:49 PM

Actually, the current generation [mk 54, 5"/62] can use 'semi fixed' rounds, with an extended propellant charge. This requires a double loading cycle.

BobK · #87 05-13-2011, 01:50 PM

Dad's hearing is not too good. Then again he is 80 and raised 7 kids (and we were never quiet!) Bet it was really loud. Think the 5 in rounds they had were self contained. This was 1950-54 I think.

Botnst · #88 05-13-2011, 08:00 PM

That would probably have been the 5" 38 cal. http://en.wikipedia.org/wiki/5%22/38_caliber_gun

projectile and charge delivered separately. My mistake, I confused it with the 3" naval artillery, which is a single cartridge. Incidentally, my dad was skipper of a Fletcher class destroyer in the Pacific (Korea) during that time.

Hatterasguy · #89 05-13-2011, 09:37 PM

Can't forget the monsters, a 2,000 pound shell over head will wake you up!

This are extremely impressive weapons, IMHO its hard to appreciate them unless you have seen them. They go way, way below deck, massive comes to mind.

Heck I got lost in the Massachusetts when I stayed overnight on her, OMFG the powder rooms all look the same after awhile!