The following information will be of importance to interrogators when questioning sur-vivors of ships sunk or damaged as a result of enemy action.

GROUND MINES

CONTACT MINES

TORPEDOS

NOISE

Dull and prolonged (rather like a depth charge) Double ex-plosion often reported due to the time lag between pres-sure wave and kinetic wave.

Short sharp loud (like a gun).

As for contact mines, but sometimes slightly muffled by torpedo thending to enter hull.

FLAME

As a rule, no flame or smell of fumes and little smoke below 50'. Less than 50' possibility of flame, fumes, and smoke.

Flame generally seen and smell of fumes of-ten reported. Much smoke.

As for contact mines.

SPLASH

Height of splash depends on depth of mine. A 1500 lb. mine in 10 fathmos gives spalsh about 50' - 100 ft. high and approximately 100 ft. across. Splash follows pressure wave at interval of seconds, depending on depth of mine. (2 seconds interval to 100 ft.

550 lb. mine at 6 to 10 ft. below surface will give large splash about 200 ft. high but not so wide as ground mine. Splash and explosion are coincident.

As for contact mines, but splash may be spread less owing to penetrating hull.

Splash generally on both sides.

Splash on one side of ship only.

EFFECT

Lifts ship. Ship whips and vi-brates Crew thrown up into the air.

Ship lurches. Crew thrown to one side. Blast effect immediately noticeable.

As for contact mines, but torpedoes tend to penetrate
hull and explode inside; hence explosion appears less violent to those on deck.

DAMAGE

Engines almost always stop-ped. Damage to bearings, beds, and castings. Ship of-ten breaks back due to hog-ging and whipping. Damage extensive, although not al-ways immediately apparent. Ship generally sinks on an even keel.

Damage localized. Ship holded. Engines often continue to function. Damage immediately apparent. Blast and splinter damage. Ship generally lists.

As for contact mines.