Ballistic Missile Submarines In Deep Underwater Collision - Updated/Bumped

It is hard to calculate the odds of a deep underwater collision between two nuclear powered ballistic missile submarines, but on the night of Feb. 3rd or 4th the unthinkable occurred. On Monday, as I noted on Twitter the French SSBN Le Triomphant (S 616) was returning home in the mid-Atlantic from a deployment when she reportedly hit an 'object, which was most likely a container' resulting in severe damage to the sonar dome of the submarine. Today we are learning that object was actually a container for the strategic nuclear deterrent of Great Britain, also known as HMS Vanguard (S28). From the Daily Mail.

French Navy sources confirm that Le Triomphant, one of four strategic nuclear submarines of the ‘Force de Frappe’ (Strike Force), was returning from a 70-day tour of duty when it collided with HMS Vanguard.

During heavy seas in the middle of the night between February 3 and 4, French sailors heard a loud ‘bang’ that all but destroyed the submarine's sonar dome.

This part of the boat should have detected the Vanguard in the first place, but Le Triomphant’s crew of 101 neither saw or heard anything before the collision.

According to reporting of both The Sun and Daily Mirror, both submarines had to be towed to port and both had visible damage from the collision. Both are lead ships of their respective countries ballistic missile submarine class. It is hard to calculate the odds of two submarines running silent at the same depth in the same part of the Atlantic Ocean and neither submarine detecting the other prior to collision. It is also particularly disturbing that the French Le Triomphant (S 616) was hit on the sonar dome and had no warning prior to collision.

Western nations have spent a fortune to upkeep strategic nuclear deterrence underwater for decades, and part of that investment has to make ballistic missile submarines very difficult to detect by passive sonar. Apparently, mission accomplished. HMS Vanguard (S28) displaces over 15,680 tons and Le Triomphant (S 616) displaces around 14,335 tons; these are gigantic submarines making any collision deep underwater very dangerous.

It is a real credit to how much attention to detail goes into the safety and survivability of nuclear submarines that all of the damage reported from both nations appears to be specific to the hull and external systems. There are no reports of damage to the ballistic missiles on either submarines, nor any leak from either nuclear reactor that powers either submarine.

Updated: I expect the details of the first reports to be inaccurate, for example, the French are not confirming anything happened, but are confirming a frigate escorted (not towed) the submarine back to port, while the Royal Navy is also claiming the submarine was not towed.

For the truth regarding the details of the accident, we will have to wait, and may not ever get the whole story. Given how odd the story was Monday regarding the Le Triomphant (S 616) crashing into an underwater container in the middle of the Atlantic, and that we are hearing official word about damage to HMS Vanguard (S28), I do believe the collision did occur. There has to be a story regarding how the Le Triomphant (S 616) hit the other submarine with its sonar and never detected it. That is very odd.