This underwater protection proved to be effective enough when, at Mers-el-K�bir on 6 July 1940, fourteen of the forty-four depth charges carried on the patrol ship " Terre-Neuve ", which were equivalent to 1, 400 kg of TNT or eight air-launched torpedo warheads, exploded within a few meters of the " Dunkerque " hull.
42.
The salvage operation was very dangerous because of the risk of radiation from the reactor, along with the presence of unexploded torpedo warheads ( about TNT equivalent each ), the 24 SS-N-19 " Granit " cruise missiles aboard ( about each ), plus a missile ejection charge ( about TNT equivalent ) in each silo.
43.
The seismic waveforms of the second event, known to be from the explosion of several torpedo warheads, also generated a high-frequency bubble signature characteristic of an underwater explosion of approximately 3 7 tons of TNT . When they compared the second event with the first, they concluded that the first event was also the explosion of a torpedo.
