...Those Marvelous Tin Fish: The Great Torpedo Scandal Avoided

[phx1138]

How about a water ram? Post-war, but the tech is not that hard to develop pre-war. Your hot run is by hydraulic action expelled and you clear datum (noise) to try again later?

I'm not sure clearing the tube was the problem so much as the hazard of it happening in the first place. I'm guessing a water ram, if fitted, would be faster than the wartime standard system, which appeared to need the tube to flood, first. (Unable to overcome the friction, otherwise?)

A water ram (or similar non-impulse system) would also remove the firing bubble, which would be a good thing. (That said, the war boats could "swallow" that, at the expense of increasing internal pressure.)

 

[McPherson]

I'm not sure clearing the tube was the problem so much as the hazard of it happening in the first place. I'm guessing a water ram, if fitted, would be faster than the wartime standard system, which appeared to need the tube to flood, first. (Unable to overcome the friction, otherwise?)

A water ram (or similar non-impulse system) would also remove the firing bubble, which would be a good thing. (That said, the war boats could "swallow" that, at the expense of increasing internal pressure.)

Dumping a hot-run torpedo with the attendant bubble was a sure way to attract attention. At least with a water column doing the shoving, you can save time on the trim out during the ejection, it should be slightly less noisy and the tube can be cleared faster. The down side is that one bets that hot-fish will be a circle jerker wanting to come back home to mother, so there might be some fancy plane and rudder work with a nose heavy boat? Not too good even with a hydraulic ejector.

 

[phx1138]

Dumping a hot-run torpedo with the attendant bubble was a sure way to attract attention. At least with a water column doing the shoving, you can save time on the trim out during the ejection, it should be slightly less noisy and the tube can be cleared faster. The down side is that one bets that hot-fish will be a circle jerker wanting to come back home to mother, so there might be some fancy plane and rudder work with a nose heavy boat? Not too good even with a hydraulic ejector.

Yeah, if you're anywhere close to an enemy, you could be in big trouble. Except, if you've got a hot run, chances are good you're setting up to shoot him anyway, so... Or you're far away & it doesn't matter.

As for the combination of hot run & circular, yeah, that could be a fun day. I'm unaware of it happening together, tho. I wouldn't rule it out, but I wouldn't say the odds are high.

 

[SsgtC]

As for the combination of hot run & circular

This just triggered something for me. Is the tech there to install an an anti-circular run feature on the Mk14? That would solve fish getting a return-to-sender message AND it would solve the hot run issue. The boat makes a 180° turn, the fish deactivates.

 

[NHBL]

I seem to recall (from long ago, so memory could be faulty) that there was talk of an anti-curcular run device, but the idea was also tossed around that it might be an option if an enemy destroyer was over a submerged boat.

Would an anti-circular run gadget turn the fish off, or simply make it dive to the bottom. A deactivated fish is still armed and dangerous, and close to the sub.

 

[SsgtC]

I seem to recall (from long ago, so memory could be faulty) that there was talk of an anti-curcular run device, but the idea was also tossed around that it might be an option if an enemy destroyer was over a submerged boat.

Would an anti-circular run gadget turn the fish off, or simply make it dive to the bottom. A deactivated fish is still armed and dangerous, and close to the sub.

I think most of them immediately deactivate the engine and then let the fish sink. If a fish is on a hot run in the tube, having it try to dive won't do any good. It'll still overheat and explode.

 

[zert]

Thanks for the update DaveJ576. The testing is starting to pay off and discovering the limitations now will lead to more ships sunk, less foul ups, and saved US lives. With being able launch air dropped torpedoes at a higher speed and elevation, this can also assist in allowing those TB crews to survive for future battles.

 

[phx1138]

AIUI, the Mark XV system was a rudder-throw limiter.

 

[McPherson]

AIUI, the Mark XV system was a rudder-throw limiter.

Yup.

The best cure for a wet heater hot-run-in-the-tube is to install a kill switch in the same leads that set the gyro in the tubed torpedo (1944) that can send a disconnect or valve close command to the fuel line to the engine. Now you have a dead fish. Eject at slow hover, turn away and let her sink.

 

[DaveJ576]

As to the hot run issue... the Mk 14/15 torpedo was designed in such a way that getting a hot run was very difficult - but not impossible. There is a tripping latch inside the tube that pushes the starting lever aft when the weapon is fired. It takes quite a bit of force (on the order of dozens of G's) to trip the lever and start the weapon. While not impossible to get a hot run on these weapons, this safety feature makes it unlikely to occur. Nautilus did experience a hot run of a Mk 15 in one of her topside tubes at Midway, but only because depth charge damage to the tube broke the starting lever on the weapon and lifted the starting piston off its seat. Most likely if this weapon had been carried internally in the torpedo room this would not have occurred.

The Mk 18 however was much more likely to hot run, and this was a dangerous situation. Being propelled by batteries, if there was a short circuit along the line the propulsion system could auto start. Short of an actual hot run, the batteries could also overheat due to short circuits, producing hydrogen gas in quantities sufficient to explode. The OTL Mk 18 was a tricky beast, mostly due to a Not-Invented-Here attitude at Newport which delayed and hampered the efforts of the Navy to get it to the fleet. Trust me, I will address this issue...

 

[McPherson]

Mark XVIII maintenance manual. After reading that horror novel, I sure wish someone had investigated aluminum seawater batteries in the 1930s instead of waiting until the 1990s.

 

[Shadow Knight]

I am really digging this TL. The research done is some of the best. Thanks for writing.

 

[DaveJ576]

Additional hot run info...

The Mk 8's carried by the PT boats also had a history of hot runs, even though their engines and starting systems were similar to the Mk 14. The tubes on the PT's were fired using a black powder charge. If the charge only partially fired - which was fairly common - the weapon only partially left the tube and got stuck, but the starting switch got tripped so you had a hot run. Without water to cool it the engine would overheat and fly apart sending shrapnel all over the deck. There was even the possibility of that event detonating the warhead and of course that would be a bad day for the PT. The fault laid not with the torpedo, but with the tube and its' firing system. Given the limited engineering capacity of the PT there didn't seem to be a better solution in 1940 when it was designed. But in my timeline there will be...

In the 1960's the primary anti-submarine torpedo in the USN was the Mk 37. It was an electric torpedo, 19" diameter, swim out, pattern running, with passive/active homing. The early versions though were quite buggy, especially in the area of her batteries. They were notorious for shorting out and overheating. Hot runs, while not exactly common, happened far more often than they should have. A hot running Mk 37 was one of the early theories that tried to explain the loss of the USS Scorpion (SSN-589). This was the leading theory until later study of debris from her wreck pretty well showed that the boat's battery, not a torpedo, was what exploded and caused her loss. By the time I arrived on the USS Darter (SS-576) in 1984 the Mk 37 had been thoroughly developed and was a pretty good weapon. Along with 12 Mk 48s in our forward torpedo room, we carried two Mk 37 Mod 3 versions in our after torpedo room until 1986 when they were finally retired for good.

 

[DaveJ576]

I am really digging this TL. The research done is some of the best. Thanks for writing.

Thank you for the comment. It is sincerely appreciated. I am glad you are enjoying the TL!

 

[marathag]

Given the limited engineering capacity of the PT there didn't seem to be a better solution in 1940 when it was designed. But in my timeline there will be...

Clamps that hard?

 

[zert]

Clamps that hard?

Wow, having the propellers open like this of a tossing wooden boat, is asking for trouble.

 

[McPherson]

Clamps that hard?

Mark XIII. And dump over the side;

is a lot safer than the gunpowder tube launch method described (^^^^) above.

 

[r1ncewind]

Will you contine this story during the war and if so will you show the war in general or continue to concentrate on torpedo rnd?

 

[DaveJ576]

It is my intention to show some of the effects that having good torpedoes would have had on the war, especially the early stages, but I do not intended to write a minute by minute narrative. As to what I think will ultimately happen, refer back to Post #1!

 

[McPherson]

Will you contine this story during the war and if so will you show the war in general or continue to concentrate on torpedo rnd?

At least 20 novels and over a hundred "scholarly" books have been written about the submarine war in the Pacific (many of them dreadful) which is astonishing, considering how little the general public knows about the bit of history. (Take me for example, I am getting an education here. Thanks, Dave.).