Not one for the sonar girls :p

[DangerousDaze]

A question for the nukes out there. It's the job of the shaft seals to stop water entering the people tank where the shaft penetrates the hull. It does this by using pressurised water from the auxilliary seawater system to leak "outwards". My question is, what happens if the pump fails? Is there a chicken switch to seal the shaft more completely possibly at the loss of propulsion? Thanks for any help.

Great site, btw. :)

Nick

[lesrae]

If I remember correctly there's an emergency/maintenance inflatable seal that can be used (I haven't seen it but imagine it's like a toroidal airbag) but the shaft can't/shouldn't turn while it's in use.

[Kapitan]

they have that problem with the russian oscar class submarines if the shaft isnt turning then water comes in (what helped kill the Kursk crew).

so clamps and special air bags have been fitted to some submarines just not all of them.

[DangerousDaze]

Thanks for the replies!

Nick

[Konovalov]

if the shaft isnt turning then water comes in (what helped kill the Kursk crew).



Is this true of all modern submarines? :o

[Kapitan]

not all i dont think as i believe only the oscar class have this issue its such a big issue with them that they have to clamp the submarines shaft before it reaches the pier hence why its toed in and out by two or three tugs.

[lesrae]

if the shaft isnt turning then water comes in (what helped kill the Kursk crew).



Is this true of all modern submarines? :o

No, it's not. Sounds like a design or maintenance fault.

[Kapitan]

its a problem with oscar and also the typhoons and delta's seems only to be with twin screwed subs western subs no clue

[Bill Nichols]

If I remember correctly there's an emergency/maintenance inflatable seal that can be used (I haven't seen it but imagine it's like a toroidal airbag) but the shaft can't/shouldn't turn while it's in use.

Righto! USS Tullibee had to use the emergency seal when their screw fell off in the Med. :o

June 16, 1978: "The propeller shaft of the TULLIBEE snaps just outside the hull causing limited engine room flooding and loss of propulsion while TULLIBEE is submerged in the Mediterranean. The flooding is stopped by tightening the emergency packing on the propeller shaft. The submarine quickly surfaces and is assisted by other US naval ships. The TULLIBEE is subsequently towed to Rota, Spain, for repairs."

http://navysite.de/ssn/ssn597.htm

[Konovalov]

How does the propellor shaft snap? Is it metal fatigue or something else?

[Kapitan]

never heard anything like that not a total loss of a propellor, heard about throwing a propellor blade HMS Onyx threw a blade during one op.

but a whole propellor what the heck?

[Letum]

throwing a blade can snap the shaft - althow i doubt this is possible in a sub

[joea]

throwing a blade can snap the shaft - althow i doubt this is possible in a sub

Arrgggh I clicked on your sig link ... braaainzzz. :hulk:

[Bill Nichols]

How does the propellor shaft snap? Is it metal fatigue or something else?

In Tullibee's case, it was a combination of corrosion and metal fatigue. :oops:

[Abraham]

Arrgggh I clicked on your sig link ... braaainzzz. :hulk:
Graaaagh!

Me too...
:oops:

Brainz, Brainz, Brainz
Where can I get a new set?
:-?

[Konovalov]

How does the propellor shaft snap? Is it metal fatigue or something else?

In Tullibee's case, it was a combination of corrosion and metal fatigue. :oops:

Ok. Thanks for the info. Should I take it that this should not have happened? Can you confirm if there was a review or alteration of maintenance/service procedures after this incident?

[Bill Nichols]

The rest of the story:

"Near Catastrophic" incident on sub probed
Mon, August 14, 1978
The Lowell Sun
Boston (AP) The Navy is investigating events that led to the breaking of a propeller shaft of a nuclear sub while she was submerged, including allegations by the crew that they would be hesitant to ever serve under the skipper again, according to a report in a Boston newspaper.
The submarine Tullibee broke its single propeller shaft June 16 while submerged in the Mediterranean Sea. The engine room flooded and some crew members said they were lucky they made it out alive. The sub is now in drydock in Rota, Spain, for repairs.
The Navy, which termed the incident "near catastrophic," is investigating reports that crewmen told the captain, Cmdr. Charles Arnest, that the shaft was cracking in seven days before it broke, according to the report. Cmdr. Arnest did nothing about the crew's warnings and omitted any reference to the warnings in his report about the incident, according to allegations by some crewmen reported by the newspaper.
Crewmembers contacted by the newspaper said the breaking shaft was the latest in a series of alleged incidents they say make them hesitant to ever serve under Arnest again.
THE NAVY, in a two-page statement, disputes the various incidents but says the shaft breaking and the unheeded warnings are being investigated by the Navy Judge Advocate General.
According to the crew members interviewed by the newspaper, the engine room crew noticed sand leaking from the shaft's bearing on June 8, shortly after the Tullibee left Naples, Italy. The shaft is a hollow tube filled with sand, which gives it stability. The engine room crew assumed the shaft had cracked inside a bearing because sand was leaking through the bearing and piling up in the bilge.
The crewmen showed the sand to the captain, who said it wasn't coming from the shaft. "His exact words were, 'No, no, that's just sand from the Naples harbor,' " one crewman said.
The crew said the captain came under immense pressure once the shaft broke on June 16 and the engine room flooded. The sub couldn't surface immediately because destroyers were manuvering overhead. Arnest ordered the ships away but had to wait a few minutes. The engine room flooded and the stern dropped about 15 degrees. However, the crew said Arnest kept "a very cool head."

Read another article here:

"Danger and Dissent on U.S. Sub"
http://www.geocities.com/weatherman5/NewspaperArticles/danger.html

:arrgh!:

[DangerousDaze]

Wow, that's not pleasant at all. I would hazzard a guess that if that shaft broke at or beyond the shaft seal they probably wouldn't have survived. As it was it sounds (from the attached article) that it broke just an inch away. Some would call that a lucky break.

Nick

[Bill Nichols]

Wow, that's not pleasant at all. I would hazzard a guess that if that shaft broke at or beyond the shaft seal they probably wouldn't have survived. As it was it sounds (from the attached article) that it broke just an inch away. Some would call that a lucky break.

Nick


Ouch! :dead:

[caspofungin]

so what ended up happening to the captain?

[Squeezmo]

The Tullibee's shaft broke due to a rear end misalignment combined with a machinsts error. The original shaft machinist went too deep on a cut between two sleeves (into the shaft metal, which is why it broke where it did)... and while in Rota the Charleston shipyard tiger team actually moved the front and back shaft holes by several inches apiece (weeks of welding, plating, and boring). After a cursory JAG investigation during which I was told it was my word vs the captain's... The skipper lied to the JAG and then in front of the crew at quarters on the work barge in Rota (it ain't slander unless it's false) about no one telling him (even though we had wrenches and air masks hanging from pipes back in shaft alley for 3 weeks before the break; AND I PERSONALLY TOLD THE Captain AND SHOWED HIM our evidence of the break)... and we eyewitnesses got told to shaddup or go to Leavenworth. NIS tortured me over this for 4 hours in a hothouse on the Goose Creek Weapons Station and forced me to sign a false (DICTATED) confession which has made my life hell to date. Come get me you Jerkoffs! I'm old enough to no longer care. Btw, the lying skipper kept his job until he later beached us at Daytona while arguing right of way issues with a sailboat over a megaphone). I got accused of calling the Boston Globe about the incident (the quoted news story in this thread), but it wasn't me... I was on watch in drydock during pumpdown when the Globe reporter was called from Rota).

[Squeezmo]

M-Div determined the shaft was breaking 3 weeks before it broke. The Captain was a real hard charger and didn't want to hear our message. So we studied prints, determined our flooding line of death and expected flooding rates so we'd know how long we had. We.... the cut all lockwire and removed the locking devices from the backup shaft seals and had duct tape wound around the last two blocks holding the emergency packing from compression so all we had to do was hit the tape and the blocks were gone. We had EAB masks modified to deliver constant pressure for working underwater and ratchet wrenches with the sockets super-glued on. The masks and wrenches joined the bands of tape as standing out hanging from the overhead at the back end of the ship. For 3 weeks, duty officers toured this area... they carried our message to the captain and were told to knock it off. During Field Day in Naples,the skip visited me while I was cleaning in the dogshack. He was in his whites (ice cream man uniform). he asked me about our evidence and I showed it to him. He later told JAG (who told me that my story was at variance with the captain's and that my word would lose) that no one warned him the shaft was breaking. I know this to be a lie and will gladly take any lie detector tests anytime.

[CaptainMattJ.]

Great Details, Mate :up:


So, pardon the ignorance, but if the shaft seal breaks, why wouldnt the sudden breach in the hull cause explosive decompression at depth?

[Oberon]

Not if you feed them regularly... :03:

[Osmium Steele]

So, pardon the ignorance, but if the shaft seal breaks, why wouldnt the sudden breach in the hull cause explosive decompression at depth?

It would be compression, not decompression, and would be totally dependant upon depth and size of the opening. A minor leak below the waterline on the surface would be a major event at test depth.

As you know, air is compressible. Assuming there is nowhere for the air in the engine room to go, flooding may be controlled when internal air pressure equals sea pressure at the given depth. "IF" people can survive at such pressure, damage control can continue. Yes, this is considered an extreme measure, not a first option.

If I've read correctly, the Tullibee's shaft broke just a hair outside the pressure hull, but close enough to leak sand back into the boat. In which case there would be time for the damage control crews to work their magic at all but extreme depth.

I'm pretty sure I have a couple of pics of "Building 597", she was pretty much welded to the pier by the time I was in Groton. She was one tough luck boat.

[Squeezmo]

The shaft broke between the inner stern tube bearing bushing and the shaft seal bushing. After the bushings were installed on the shaft, a machinist cut a relief between them that was then filled with rubber for the emergency shaft boot to seal against. The remains of the shaft plugged all but about 3 square inches of the hole the shaft went thru. Since part of the shaft was still in the hole, that 3" was our flooding rate. But we knew it would do this before it broke because we researched it after the command blew us off.

[Squeezmo]

We sent our diver into the water and he told us the prop was still with the boat, just a ways back. When the shaft broke, it slid out the stern tubes but hung up at the end where the shaft had mushroomed a bit while twisting apart. We cabled it to the boat for the tow home. Looked funnier than hell when they pumped down the drydock.

[Squeezmo]

The screw is also at the center of the hull cross section so the boat on an even keel would flood at least 50% if the shaft hole were suddenly opened up fully. We would have been dead with the water 6 feet lower than the shaft penetration in the engineroom. As it was, our feet got wet in Lower Level before we began moving water off the boat and we had calculated our demise would occur at 6" above the lower level deckplates due angles caused by the loss of balance causing ballast tank air to spill out which would have been all she wrote for us.

[Squeezmo]

We did shoot a Red Combo flare... in record time (we'd practiced this, too)... and we had a manual signal ejector aft... Control didn't think of that either. I yelled over the chain we were gonna do it as I ran by Maneuvering. We also hooked a submersible pump to a hose connection on the suction of the drain pump and moved water off the ship at twice the design rate... we thought that one up and practiced it in advance, too. But no one knew the shaft was breaking...

[Squeezmo]

nuff said

[Bubblehead Nuke]

I find it interesting that I had posted on this thread years ago about the shaft seals and how they worked.

I find that that post is now gone, as it many of my older posts concerning things of this nature....

Very interesting.

Back on topic:

Great Job Squeezmo.

We had failing shaft seals on my boats as well. Primary seals were blown and the secondaries leaked so bad that greater than 300 or so feet we had to run the drain pump constantly to keep up with the engress. Everyone, and I mean EVERYONE in the engineering department, knew how to put the emergency seals on. We had an unofficial afterwatch watch assigned just to monitor them.

We were on an OP and considerations of the mission took priority. Captain came back more than once and said we were overreacting. This is with a spash skirt rigged around the shaft seals and the home made 'octopus' to get the water to various funnels so that seawater went into the after drain tank instead of the bildges.

Fun days were had by all. We hit the USA and were in the dock immediately after the two week post deployement standdown. They bumped a boat to get us in.

Oh.. and that Captain?? He is NAVSEA08 now. That scares the hell out of me more than the badly leaking seals did.

[nikimcbee]

How fast would the boat take on water? Could the crew even keep up with a failure like that? Could they even contain it?

[Osmium Steele]

nuff said

BZ brother. :yeah:

[Bilge_Rat]

How fast would the boat take on water? Could the crew even keep up with a failure like that? Could they even contain it?

Depends how deep they are and the outside sea pressure. The crew would have been in very serious danger.

USS Squalus sank in 1939 after failure of an induction valve. She was not very deep at the time:

http://en.wikipedia.org/wiki/USS_Squalus_%28SS-192%29

HMS Thetis sank in 1939 after someone opened the torpedo tube door in error. She was on the surface at the time:

http://en.wikipedia.org/wiki/HMS_Thetis_(N25)


USS Thresher was lost in 1963 during a deep dive. The most likely theory appears to be the failure of a joint in a salt water piping system due to the sea pressure.

http://en.wikipedia.org/wiki/USS_Thresher_(SSN-593)

[kraznyi_oktjabr]

USS Squalus sank after failure of an induction valve. She was not very deep at the time:

http://en.wikipedia.org/wiki/USS_Sailfish_(SS-192 (http://en.wikipedia.org/wiki/USS_Sailfish_%28SS-192))
Your link is to non-existent article on USS Sailfish (SS-192). Did you intend to link to this? http://en.wikipedia.org/wiki/USS_Squalus_(SS-192) (http://en.wikipedia.org/wiki/USS_Squalus_%28SS-192%29)

EDIT: Ah your link is broken because last ")" mark is not included in link.
EDIT#2: Same applies to all links.

[Bilge_Rat]

strange, for some reason I cant get the proper links to show up in Wiki?

[Squeezmo]

Our floodiing rate was about 5,000 GPM (calculated, and later confirmed using the high water marks in the bilge and the logs showing how long the flooding lasted). No way our pumps could keep up. As it was the drain pump was badly designed with gland seal from aux seawater.... so we lost seal pressure on the surface and the pump would get airbound sucking air in through the packing (yes, packing) if we tried to exceed about 75 GPM. We fixed that by hooking a submersible pump to a hose connection and pushing the water thru the pump... even then, it got us only 500 GPM (which was way above the pump ratings), so we had to stop the flooding to live.

[Squeezmo]

We also later found that the 597 had a corrosion pit in the engineroom bilges under some lead. When we cleaned it out we found it to be about 3 feet in diameter and half the hull thickeness deep (HY40). The Navy then limited us to a very shallow depth... a restriction promptly violated during a loss of CO2 removal casualty (the Engineroom Lower Level watch woke up the Control watchstanders as the ship was passing a grand and flying towards the bottom).

We had all kinds of close calls....

[nikimcbee]

That's scary stuff.:salute: Thanks for your service.:salute:

[Catfish]

Wow thanks for this story ! :salute:
Good job -


How was it done with the older Diesel subs - some of them also went down to 900 feet - what did they do to keep out the water ?

[Squeezmo]

mechanical seals seal tighter with increasing differential pressures.... with a good seal it leaks less at depth.