This is coolbert.
During that first half of the year 1968 four submarines having gone to the bottom due to unexplained circumstances. A fifth boat also possibly lost.
* Dakar. Israeli.
* Scorpion. American.
* Minerve. French.
* K-129. Soviet.
* K-27. Soviet.
From the book "Silent Steel" by Stephen Johnson:
"On January 25, the Israeli Navy submarine Dakar . . . was lost a day's sailing from Haifa."
"Just two days after the Dakar's loss, the French diesel-electric submarine Minerve sank off Toulon"
"The outbreak of submarine disaster had not yet run its course. Before the end of the year, the secretive Soviets would lose two submarines - - one on March 8 in the Pacific and another rumored lost in the Arctic Sea. The Scorpion would be lost on May 22."
At least four submarines sunk with all hands lost with a period of less than six months, that first half of 1968.
Unprecedented and most troubling and as might be expected controversial.
That rumored fifth submarine apparently run afoul but not necessarily gone to the bottom perhaps the Soviet K-27, major reactor problem with loss of life, the vessel never sailing for an additional combat mission.
Submarines in the modern era assigned missions of considerable length, able to operate at greater depths and higher speed for a prolonged period. EVEN A NUCLEAR POWERED BOAT ABLE TO SUBMERGE AND REMAIN SO FOR MONTHS ON END.
Consider that the current HMS Astute [nuclear powered English fast attack boat] is considered to be the MOST COMPLICATED THING EVE4R MADE BY MAN.
Taking into account the totality of the vessel, the ship itself, the weapons [missiles and torpedoes], the reactor, the electronics with associated computer controlled systems, etc. Complex.
American submarine commanders too even encouraged to take risks on some occasion that can be reasonably seen as FOOLHARDY WITH HINDSIGHT. Measured audacity it would be referred to. Nothing ventured nothing gained I guess was the outlook.