School of the Boat for 5 Nov 08 (Torpedo Tubes)

[JTheotonio]

sterns shots were harder (make that more difficult)

[Darrin]

Or so I have heard, although how hard could it be honestly to take a bearing on a target and then add 180 degrees to get your stern on the track that it needed to sink it's intended target?

Me thinks that it was the Officers who had the problems shooting the stern tubes and not our bretheren TM's

[JTheotonio]

agree on that - no TM problem, it all came from the conn.  But think about the shot - instead of adding, there is a lot of subtracting going on.  Both you and the target are moving away.  Angle of the bow, speed and distance are all increasing or can be increasing.  You're talking periscope data and TDC inputs, so everything is backwards. 

[Mark Sarsfield]

Even more complicated is if you are driving the boat in reverse to get a better angle for a stern shot.  I've gotten confused more than one time doing stern shots in various sub sims.  It's a lot to remember when it's just one person.

[etkfixr]

Concerning the tubes, what are water slugs and air shots and how did you do them?  Any other cool questions about the primary weapon system?  Terry

[Darrin]

Terry,
the one thing that you have to remember about the tubes is that a "water slug" is what is used to exercise ALL of the tube mechanism's  at their required depths without shooting a weapon out.. Now with a "air shot' that is a new term to me and that I think is just cycling the valves for maintenance which I have done many times on a newer version of these tubes on a Balao.

[JTheotonio]

Terry - here is some more information.

Water slugs are fired as training, exercising the tube mechanisms, and to check the firing valve clearances. 
When checking the firing valve clearance water slugs were used with the idea of determining impulse tank pressures which would 1) eliminate the launching bubble as much as possible, and 2) favor the run of the torpedo launch in such a way to have the minimum tendency to either cause the torpedo to broach or to take an initial dive.  At one time the impulse tank pressure was not varied for depth.  With the impulse tank pressure at 400 psi, the firing valve should exert a tube pressure of about 59 to 65 psi while on the surface.  Later after a lot of testing we used different impulse tank pressures based on depth of the sub when firing a torpedo.  Impulse tank pressures varied form 300 to 525 psi.

When firing a water slug we did not have the poppet valve on because without a torpedo or even a dummy in the tube it would open immediately when the service line pressure was allied to the operating cylinder.  So we gagged the poppet to fire water slugs.

Air charges were fired inboard.  Again this procedure was used for training and exercising certain operating mechanisms of the tube such as the firing mechanism, stop mechanism and the gyro setting spindle retracting mechanism.

To fire a air charge you open the breech door and leave it open until the interlocking mechanism has been reconnected and locked.  Then withdraw the depth and speed spindles.  If you have a torpedo loaded you need to withdraw the gyro setting spindle and pull the torpedo back a few inches.  This prevents it from getting pushed forward past the stop bolt.  Then you can unlock and remove the padlock from the firing interlock signal arm and raise the arm to a vertical position. Open the firing impulse stop valve. Charge the impulse tank to about 100 psi (we were warned not to go above this pressure). Throw the firing interlock level to the Tube Ready to Fire position.  The tube was then ready to fire the air charge.  So when ordered you fired the tube. Then return the tube to normal making sure all the interlocks are back in place and locked.

If you just got out of the shower, you could stand at the breech door and “blow dry” your hair.  (OK just kidding)

[BrokenArrowtiger]

I got a question for yall. How Long would it take to load,fire and then reload a torpedo during ww2. I know the crews of the Wahoo Tautog and silversides could do it quit well. Its wierd the torpedo tubes on the outside of the boat look soo smaller then the torpedo it self.

[Mark Sarsfield]

I've heard as short as 3 to 5 minutes for experienced crews and as long as 12 minutes for trainees/NQPs.

[BrokenArrowtiger]

Sweet! todays subs are more machinereized and electronics. Those precious minutes could determine weather u get out alive or not

[Darrin]

everything is done by hydraulics now in the torpedo rooms and from what I understand it is nearly all push button and very little man power these days

[BrokenArrowtiger]

Yep. but on one hand if u were ina fight u would have quicker chances to fire ur torpedo or rocket off

[Mark Sarsfield]

We would like to get a "light weight" mock-up of a full-size torpedo for Batfish made so that we can demonstrate loading to a captive audience.

[Darrin]

Terry,

For a "quick response" the torpedo is by far the best option because of the depth and speed that you can launch one from these days, we practiced "SNAP SHOT'S" all the time.  And what that means IF someone fires on you and you start hauling arse out of the way of the incoming weapon and you will litteraly fire and forget the weapon and turn and burn as fast as you can out of it's way, very fun evolutions for us TM's and for those on the Helms/Planes watch and the Throttleman because you litterallly get to see how fast you can get the boat to go as quickly and as noisily as possible.  Sad part is if the TM now MM is half asleep or the boat was going at a pretty good speed already, he may not get the outer doors open before the speed gets too fast. BTDT a few times.    The Honolulu when I was on her could open her outer doors at a higher speed than any other 688 in the fleet due to a mod (that was taken out during the '93 shipyard period), that was nerve racking when I rode other boats and their tubes wouldn't/couldn't open at the same high rate of speed that I was truly used to.

A Tomahawk you had to come up to a certain depth and a slow speed to launch it and as soon as it broke the surface of the water and then EVERYONE knew exactly where you were and then you had to run like you know what if someone was in the area and taking the boat as deep as it could go trying to find the thermal layer (sound bounces off of a cold water layer BTW).

[BrokenArrowtiger]

Dang! High weopontry mark if u had a mock up torpedo ya i would be in the audience no doubt!
Darrin i would be scared as hell to fire off a missle iv heard of WW2 subs doing the exact same thing u described ur being shot at and u better get ur arsh as far away as u can and pray u scored a lucky shot now a days though the technology is so great that being accurte on those kind of shots is quite possible technology has grown soo much over the past 10 or 20 years its just amazing how nuclear theese subs truly are i can garuntee some of theese subs can carry  Small atomic bombs and i bet some probley do in worst case senario