C/W Watson
                      249 C/W Robertson
Top Secret.
    Copy No. 171    14
    U-boat  "U 249"
    Rec.     26.3.44.
    Reg No:  Top Sec. 30
    Encl.      ---____________
Current Orders No. 40 of Feb. '44.
  Tactics for night attacks by anti-submarine aircraft.  
1) A/S fighter aircraft fly their patrols over established routes which are changed daily, and are so arranged that the area searched is permanently covered.  Height of aircraft chiefly between 600-1800 m.  Locating apparatus sometimes switched on permanently, sometimes kept in reserve.  Range of the apparatus is great, normally  the broadside of the U-boat can be picked up at 20-30 nautical miles, in good locating conditions the range increases.  Aircraft anticipating the boat, sends off a wireless signal for bringing up reinforcements, and flies at low altitude in order to maintain contact, and to be able to go in to the attack at any time.  By maintaining contact, course and speed of U-boat can be gradually reckoned.  If reinforcements do not arrive promptly, the contacting aircraft attacks alone.
2) Attack at a height of 15m.  At the first approach from chosen direction.  On light nights after sighting a boat first choose a favorable position for attacking.  A diagonal flight over the boat is considered the most favorable.  Approx one nautical mile from the target switch on searchlights; on light nights or when there is much phosphorescence, no searchlight.  Dropping of bombs, 2-6 bombs by sighting.  At the same time dropping of flares and firing of aircraft guns,
  If the first bombing run does not succeed, a fresh run and dropping of bombs.  Lately target has been frequently lit up by flares, then an attack from favorable position.  A boat observed several times: after boat has been identified by searching craft, rendez-vous of 3 searching aircraft in the vicinity.  After approximately one hour, first attack whereby one aircraft is lit up, the attacker being the other.
3) After the bombing run over the target.  A new run is directed according to light and horizon:
  a)  If horizon is difficult, flying and curving must be done by instruments (artificial horizon), therefore withdrawal, blind curve, fresh bombing run to the location.  Aircraft returns after about 5 mins.  That means that the boat can submerge after the run.
  b)  If the horizon is clear, flying can be visual, as in daylight, thus: withdrawal, sharp curve, fresh attack after about a minute, which means that the boat remains on the surface.  Speed of second attack depends on whether the target remains in view during curving.
4) Most favorable for A/S fighters are moonlight, calm night; unfavorable, dark nights with poor visibility, fog or storm; bombing only possible by instrument, but too inaccurate.
5) Tactics for daylight attacks - see standing orders 181, appendix 3.
6) According to prisoners' statements carrier borne planes on U-boat patrol now attack in pairs, with different missions, probably crosswise in most cases; a fighter plane with cannon keeps down the Ack-ack of the ship.  This procedure is said to have been frequently carried out in the maritime area West of Norway.
  Defence:-  Boat is to pick enemy up on FUMB or FUMO and search for him  If boat must remain on surface, ward off aircraft by opening fire in succession in good time.  Do not allow aircraft equipped with guns to fire on the gun crew from behind.
7) A U-boat from North Waters reports its experiences in fighting off carrier-borne aircraft.  If time permits, dive immediately in the presence of carrier borne aircraft, since the contacting plane can bring to the spot in a very short time, as many planes as required.


    C/W Watson
          C/W Robertson
  Other times I have observed biplanes in combination with fighters.  
          Fighters attempt to force the boat to remain on the surface by immediate attacks, and call up reinforcements.  Should the U-boat dive, two depth charge are dropped by biplanes.  Should the boat remain on the surface, the contact plane should be kept at a distance only with 3.7 cm. (gun).  The 2 cm. guns should not be manned.  A few as possible should be on the bridge so that diving can be carried out quickly at a favorable moment.  



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