Accidents.

This is coolbert:

From the book "Silent Steel" by Stephen Johnson:

"Although the navy lost twenty-two submarines in noncombat mishaps between 1900 and 1968 - - an average of nearly one submarine every three years - - the loss of Scorpion marked a sharp break in that deadly cycle."

"Although accidents, fires, fatalities, and battery mishaps still occur, the U.S. Navy did not lose a single submarine between 1968 and 2004 [and since that time as well]. By any measure, this is a remarkable achievement in safety, although in was preceded by decades of tragedy and the destruction of two nuclear powered attack submarines with all hands within a five-year period."

American nuclear submarines [all submarines period during the era of the Cold War and beyond?] having to undergo periodic overhaul, refit, refueling.

That protocol for certifying a boat that has undergone "periodic overhaul, refit, refueling" ready for combat mission quite rigorous and extensive.

The vessel first certified as to seaworthiness. Merely able to sail, submerge, and do so with regard to tolerance and specifications.

Also needing to be certified as to combat readiness, the commander and crew able and ready to sail the ship into battle and sink enemy ships. A commander and crew able, fit proficient.

Only after the two stage certification process completed is a submarine allowed to depart on a combat mission or what might be deemed as routine patrol [some would suggest that no patrol is routine!]..

American submarines during that era of the Cold War carrying live torpedoes to include atomic munitions [modern attack boats do not carry atomic weaponry].

Certified does not necessarily mean the vessel during a voyage will not encounter problems of some sort.

During several missions prior to sinking the USS Scorpion for instance was reputed to have had:

* Excessive freon consumption [but not beyond acceptable levels].
* Excessive hydraulic fluid consumption [but not beyond acceptable levels].
* Excessive leakage at the seal where the propeller shaft meets the pressure hull [but not beyond acceptable levels].

As many AS SEVERAL DOZEN WORK ORDERS WILL BE GENERATED DURING A SINGLE SAILING OF A SUBMARINE! This is not considered to be unusual, NONE of those difficulties as encountered considered to be so serious as to endanger mission or the boat.

Don't even think any of this stuff is going to be easy. As previously mentioned, these submarines are among the most complicated if not THE most complicated things made by man.

NO ONE said this was ever going to be easy.

coolbert.