For Questions That Don't Merit Their Own Thread

[Racescort666]

What is the transition speed/mach number from friction heating to compression heating in aircraft/spacecraft?

@ARS, you should play World of Warships, excellent battleship duels. It is worth noting that historically, hitting the conning tower (bridge during combat) is bad but not totally fatal to a combat ship. Hitting the magazine on the other hand, well, HMS Hood went down in 3 minutes after the Bismark hit her in the magazine and only 3 men survived. 

[DDE]

3 hours ago, ARS said:

On 1-1 battleship duel, if one battleship (with sheer luck) managed to land a main gun shell on another's bridge, causing it to explode and completely destroying the bridge, does it becomes an ship equivalent of "headshot"? Does it disables the ship, heavily crippling it or not a big deal at all and still combat capable? Especially since the bridge is the command center of the entire ship

The bridge included a tiny battle comparment, a conning tower, that was clad into up to half a meter of steel. Everything else was paper-thin, a powerful protection against shells in itself as they tend to overpenetrate readily. Plus there was also a degree of redundancy that allowed full combat operations to be resumed within minutes from backup command posts, and the enclosed CIC was beginning to emerge by WWII.

That said, battleship captains avoided the conning towers - and it’s unclear how great the cost were. Say, South Dakota was blind and deaf for much of the battle of Guadalcanal. Was that because Kirishima’s battlegroup thoroughly raked her superstructure with artillery - or because some time prior an engineer locked her breakers open and the ship was entirely out of power? One thing’s clear, an armoured bridge would have probably saved some trouble for Hiei, which, some time prior but in nearly the same place, came under machine gun attack from a destroyer 6 meters away

[kerbiloid]

Spoiler

4 hours ago, p1t1o said:



 

Is this button switch to the right from the door the only way to open it?

[Gargamel]

9 hours ago, ARS said:

On 1-1 battleship duel, if one battleship (with sheer luck) managed to land a main gun shell on another's bridge, causing it to explode and completely destroying the bridge, does it becomes an ship equivalent of "headshot"? Does it disables the ship, heavily crippling it or not a big deal at all and still combat capable? Especially since the bridge is the command center of the entire ship

WWII era battle ships also had "directors", which were basically spotters that helped coordinate the firing of the guns.  They were usually located in spots other than the bridge, and would continue to  press any attack.  Without direct order's from the bridge, however, they would have to choose their own targets, and that might not be the best tactic for the ship over all at that time, running against the ideas of whoever was trying to re-establish command of the ship. 

[ARS]

But what about steering gear? If the bridge gets destroyed, then there's no control of rudders right?

[magnemoe]

31 minutes ago, ARS said:

But what about steering gear? If the bridge gets destroyed, then there's no control of rudders right?

You can control rudders from other places at lest machine room even on civilian ships. Its hydraulic after all. 
Main problem is you loose coordination, some has to order the machine room to do an turn, tell the guns that target to prioritize and so on. also if you have to turn fast to avoid torpedoes you have an problem. 

[DDE]

5 hours ago, ARS said:

But what about steering gear? If the bridge gets destroyed, then there's no control of rudders right?

An auxiliary steering room is invariably present, almost always pretty close to the actual steering gear. That’s located aft - remember where the wheel was on sailships?

11 hours ago, Gargamel said:

WWII era battle ships also had "directors", which were basically spotters that helped coordinate the firing of the guns.  They were usually located in spots other than the bridge, and would continue to  press any attack.

That said, they had to have direct LOS, and this weren’t the most protected part of the ship, although there tended to be at least two covering every sector. They handled not tactical command but actual gun plotting, literally controlling turrets and housing the radars and the gun computers.

Here’s one for the big guns:

And here’s a small post for a destroyer’s 40 mm:

Before the age of radar really set in, these things were mounted as high as possible. So, the topmost bit on the Yamato is a movable sensor turret, with a massive old-school coincidence rangefinder backfitted with a pair of radar antennae.

As the final backup, you had individual turret crews controlling their weapons manually.

Edited January 26, 2019 by DDE

[Gargamel]

13 hours ago, magnemoe said:

Main problem is you loose coordination,

That's the thing.   Everything on these age of ships was controlled manually, in some form or another.   They didn't increase the throttle and the engines immediately sped up, they sent a signal to the engineer and they increased the throttle.  

Ok, there were some things that were directly controlled, like the rudder, but they all had manual backups of some sort.  

But as Mag said, you needed someone to coordinate all of it together, and that was the job of the bridge. 

[XB-70A]

9 hours ago, DDE said:

zip

I went to visit the museum of the USS Alabama (BB-35) during last December, turrets no. 1 & 2 are open and somewhat accessible, here is a picture of the (monstrous) telemeter and the post of its own fire director in the 2nd turret:

 

 

 

[Green Baron]

Well, the rudder(s) of huge merchant or military ships can't be controlled manually. They are too heavy and profiled and love to move about when not in perfect equal flow. Forces in the range of many tons are needed to move and hold them in the flow. This can only be done with the help of hydraulics. For a balanced steering there can be two cylinders left and right of the shaft that push and pull equally against an eccentric (what is the correct technical term for a lever at a right angle on an axis ?) on top of the rudder shaft(s).

On smaller boats (if not tiller steering) the helm turns a cog over which a chain runs, that ends in wire cables on both ends. These are turned around under deck and one end goes from the one side, the other from the other side around a quadrant that sits right on the rudder shaft. This mechanism can be configured without slack and holds even in dynamic conditions. It is old and works.

Tall (sailing) ships have more than one steering wheel (helm) along an axis and more than one chain to move the quadrant(s). On occasions, more than one person (6, 8) are needed to hold a course. I can tell from experience that a 14m boat in dynamic conditions can not be steered against the sheets and flow even by a strong person.

All of these methods need a mechanism to report the exact rudder position and for fine adjustment of the mechanics and they must not slack, not even slightly, or bad things can happen :-)

Was that understandable ? Sorry if not ...

tl, dr: Big ship: hydraulics, small manually controlled ships: quadrant. Or tiller. Or outboarder ...

Edited January 26, 2019 by Green Baron

[Gargamel]

3 hours ago, Green Baron said:

Well, the rudder(s) of huge merchant or military ships can't be controlled manually

When we said manually, we were referring to independently of the bridge.   As in the engineering crew has the ability to control them if needed. 

[Green Baron]

16 hours ago, Gargamel said:

When we said manually, we were referring to independently of the bridge.   As in the engineering crew has the ability to control them if needed. 

Yep, if they are hydraulic, then they can potentially be controlled from anywhere where a cable leads.

Edited January 27, 2019 by Green Baron

[Racescort666]

On 1/26/2019 at 3:18 PM, Green Baron said:

what is the correct technical term for a lever at a right angle on an axis ?

Bellcrank, although I would have called the quadrant you linked a bellcrank as well.

[wumpus]

On 1/27/2019 at 4:40 AM, Green Baron said:

Yep, if they are hydraulic, then they can potentially be controlled from anywhere where a cable leads.

The Bismark was doomed when a bomber destroyed her ability to steer (so the Royal Navy could "simply" go finish her off).  I've always assumed the rudder was hit (I think that is often the explanation), but it could have been anywhere that didn't have the required redundancy.

[StrandedonEarth]

15 minutes ago, wumpus said:

The Bismark was doomed when a bomber destroyed her ability to steer (so the Royal Navy could "simply" go finish her off).  I've always assumed the rudder was hit (I think that is often the explanation), but it could have been anywhere that didn't have the required redundancy.

I haven’t read the account of her sinking, but the bomb could have jammed it up so it simply couldn’t move no matter where it was controlled from. No doubt the engineering crew was frantically working to get the rudder moving again (fixing the actuators or clearing the jam), assuming it wasn’t blown clean off. 

[p1t1o]

Looks like the rudder itself was physically jammed.

"The torpedo hit aft, however, doomed the
German battleship, since it jammed her rudders
while Bismarck was executing a sharp port turn.
According to the senior surviving officer, the rudder
indicator locked at 12 degrees to port after the hit.
As is typical when hits take place near the bow or
stern, the ship experienced a rather severe transient
whipping response that damaged equipment not
designed to resist such forces. The most severe
damage was to the stern overhang structure. Tears
were opened in the side shell and bulkheads
adjacent to the damaged area and the smoke-screen
generating plant was completely destroyed. The
propellers, also quite near the blast, were
undamaged. Judicious use of these permitted the
ship to maintain headway, but little else. Unable to
steer, Bismarck could no longer avoid interception
by her vastly superior fleet of pursuers.  "

 

"A MARINE FORENSIC ANALYSIS of HMS Hood and DKM Bismarck"

https://web.archive.org/web/20110728032446/http://legacy.sname.org/committees/design/mfp/website/recent/research/hood_bismarck_1.pdf

 

 

And to speak to its "combat worthiness" at this time:

"Although Bismarck’s main and secondary
armament was in essentially perfect condition at the
beginning of the action, her gunfire control systems
on were destroyed very early in the engagement and
she scored no effective hits on her enemies."

 

An interesting note - a torpedo hit was actually recorded on her superstructure - although this, apparently, is not completely unheard of when a ship capsizes.

[tater]

<sigh>

 

[tater]

(for those of you who are substantially younger than I am, the above image is Judy Resnik. I had a huge crush on her back in the day, and 33 years ago she was on Challenger.)

[Mad Rocket Scientist]

10 hours ago, p1t1o said:

Looks like the rudder itself was physically jammed.

Spoiler

 

"The torpedo hit aft, however, doomed the
German battleship, since it jammed her rudders
while Bismarck was executing a sharp port turn.
According to the senior surviving officer, the rudder
indicator locked at 12 degrees to port after the hit.
As is typical when hits take place near the bow or
stern, the ship experienced a rather severe transient
whipping response that damaged equipment not
designed to resist such forces. The most severe
damage was to the stern overhang structure. Tears
were opened in the side shell and bulkheads
adjacent to the damaged area and the smoke-screen
generating plant was completely destroyed. The
propellers, also quite near the blast, were
undamaged. Judicious use of these permitted the
ship to maintain headway, but little else. Unable to
steer, Bismarck could no longer avoid interception
by her vastly superior fleet of pursuers.  "

 

"A MARINE FORENSIC ANALYSIS of HMS Hood and DKM Bismarck"

https://web.archive.org/web/20110728032446/http://legacy.sname.org/committees/design/mfp/website/recent/research/hood_bismarck_1.pdf

 

 

And to speak to its "combat worthiness" at this time:

"Although Bismarck’s main and secondary
armament was in essentially perfect condition at the
beginning of the action, her gunfire control systems
on were destroyed very early in the engagement and
she scored no effective hits on her enemies."

 

An interesting note - a torpedo hit was actually recorded on her superstructure - although this, apparently, is not completely unheard of when a ship capsizes.

Those line breaks make my brain try to rhyme the "verses" for some reason. It helps that it uses "doom" in the first line, which sounds like some kind of epic maritime ballad.

[tater]

Bismark was an anachronism, among other anachronisms (BBs commissioned right before or during WW2).

Bismark put up a lower mass of AAA fire than a single, later war refitted USN Fletcher Class DD. Gun laying for the primary turrets is meaningless vs aircraft (any aircraft). (OK, there's something to be said for the USN's 5/38 DP )

Edited January 29, 2019 by tater

[DDE]

18 hours ago, tater said:

(for those of you who are substantially younger than I am, the above image is Judy Resnik. I had a huge crush on her back in the day, and 33 years ago she was on Challenger.)

This thread just got a lot weirder. Do we start posting Anne Fischer images?

10 hours ago, tater said:

Bismark was an anachronism, among other anachronisms (BBs commissioned right before or during WW2).

Bismark put up a lower mass of AAA fire than a single, later war refitted USN Fletcher Class DD. Gun laying for the primary turrets is meaningless vs aircraft (any aircraft). (OK, there's something to be said for the USN's 5/38 DP )

It was anachronistic in more ways than one. It was, for example, the first battleship in years to have a conventional main armour belt at the expense of protecting the citadel against long-range plunging fire.

...or aircraft bombs.

Limited AA was, TBH, normal for the immediate pre-war years. If you didn’t have numbers “20” and “40” in your list of armaments you didn’t have a chance.

Bismarck’s AAA inferiority was further boosted by her non-DP 150 mm secondaries. It’s not the worst case - lots of pre-war Soviet Wunderwaffles had triple 180 mm secondaries.

Here’s Ansaldo’s proposal for the first Soviet battleship... but if anyone asks, we don’t cooperate with fascists:

We don’t cooperate with capitalists either:

And please don’t call it a battlestar.

Edited January 29, 2019 by DDE

[wumpus]

20 minutes ago, DDE said:

This thread just got a lot weirder. Do we start posting Anne Fischer images?

Considering the date, it seemed appropriate.  I also had no idea that the "main engineering lecture hall at Maryland" was named after her (must have been after I graduated: I don't think we had a "main lecture hall" in any engineering building when I was there, but there is a new engineering building now).

23 minutes ago, DDE said:

It was anachronistic in more ways than one. It was, for example, the first battleship in years to have a conventional main armour belt at the expense of protecting the citadel against long-range plunging fire.

...or aircraft bombs.

Limited AA was, TBH, normal for the immediate pre-war years. If you didn’t have numbers “20” and “40” in your list of armaments you didn’t have a chance.

Bismarck’s AAA inferiority was further boosted by her non-DP 150 mm secondaries. It’s not the worst case - lots of pre-war Soviet Wunderwaffles had triple 180 mm secondaries.

The rudder was destroyed by a biplane carrying a torpedo.  The armor was in the right place for the aircraft used against it (of course, had it lasted longer it would have been obsolete soon enough), but I'd expect any sort of anti-aircraft to be able to take out a biplane (although riddling cloth with bullets isn't all that effective).

No idea if the brits could have mounted proper bombs to the Swordfish or knew enough about the Bismark's construction (how do you hide the construction of a battleship?) to mount bombs.  Sometimes its better to be lucky.

[kerbiloid]

3 minutes ago, wumpus said:

No idea if the brits could have mounted proper bombs to the Swordfish or knew enough about the Bismark's construction (how do you hide the construction of a battleship?) to mount bombs.  Sometimes its better to be lucky.

Spoiler

 

[StrandedonEarth]

1 hour ago, wumpus said:

Sometimes its better to be lucky.

Gotta be good to be lucky, and lucky to be good!

(I believe that’s a goaltender’s/goalkeeper‘s motto)

[tater]

2 hours ago, DDE said:

This thread just got a lot weirder. Do we start posting Anne Fischer images?

It was the anniversary of Challenger.