Précis of
Attacks by SPEEDWELL and MARNE
Date: 13.4.42
Time: 2029
Position: 73° 23’ N, 19° 30’ E.
Depth of Water: Over 100 fathoms
Weather: Wind SW Force 3, Sea calm, Visibility 4 cables.
NARRATIVE
SPEEDWELL was stationed on the starboard side
of Convoy QP10 and at 2026 obtained an asdic contact on her
starboard bow at a range of 1,500 yards. SPEEDWELL turned to
investigate and at 2029 a U-boat was seen on the surface steering
as if to attack MARNE or a leading ship of the Convoy. SPEEDWELL
increased to full speed in order to ram, apparently not having
been observed by the U-boat. It was considered essential, however,
to open fire on the U-boat in order to force it to break off its
attack and dive. The first salvo was well over the target but had
the desired effect as the U-boat dived immediately and the
attention of MARNE was called to the bearing. SPEEDWELL adjusted
course to carry out a depth charge attack aiming 40° ahead of the
contact, and at 2032 dropped a pattern of four depth charges by
recorder. The depth charges were set to 150 and 250 feet and were
seen to fall immediately ahead of the U-boat’s line of advance.
The port thrower misfired but the charge from the starboard
thrower was seen to fall in the middle of a large air bubble of
about 20 feet in diameter. This air bubble was thought to indicate
that the conning tower hatch or some other vent had not been
properly closed when the U-boat dived.
MARNE had altered course to counter-attack, and
SPEEDWELL had to turn sharply to avoid a collision. SPEEDWELL
regained contact however at a range of 800 yards before turning to
attack again. MARNE's counter attack was frustrated but she
obtained contact whilst opening the range for a deliberate attack.
This was commenced from a range of 600 yards as it was feared that
the U-boat might surface and escape if contact was lost. At a
range of 300 yards the bearing of the contact moved rapidly to the
left and MARNE altered course to head it off. At 2037 a pattern of
five depth charges was dropped set to 150 and 250 feet, contact
being held until the time of firing. MARNE regained contact at
2040 but classified it as ‘doubtful’. Further doubtful contacts
were obtained and at 2040 SPEEDWELL dropped a single depth charge
set to 350 feet roughly in the position of her first attack. It is
stated that on the run-in, echo contact had gradually faded and
the target appeared to be stationary.
Both ships searched in the vicinity and at
about 2115 SPEEDWELL states that a large patch of oil was sighted
but that there was no wreckage. As the Convoy was without
protection on the starboard side, both ships set course to rejoin
the convoy and at 2144 had regained their station.
SURFACE EVIDENCE
U-boat was sighted on the surface after asdic
contact by SPEEDWELL. SPEEDWELL's first attack was seen to be on
the U-boat's track. SPEEDWELL saw oil after contact had been
lost.
ASDIC EVIDENCE
Asdic conditions were good until wakes and
depth charge patterns caused interference. Both ships have
forwarded track charts and SPEEDWELL has forwarded a recorder
trace.
CO'S OPINION
SPEEDWELL considered it very unlikely that the
U-boat could have survived either attack.
RAD
HF's OPINION
It is considered that both ships used too deep
depth settings on the depth charges. The interval between the
U-boat diving and the attacks being carried out was so short that
the shallowest settings compatible with the ships’ speed should
have been used. The result of the attacks cannot be definitely
stated owing to the lack of visible evidence. It is considered,
however, that the charges exploded abaft and below the U-boat in
both attacks and although the U-boat may have been damaged there
is no evidence of destruction.
SUBMARINE TRACKING ROOM'S OPINION
There is no tracking evidence of damage.
DECISION OF U-BOAT ASSESSMENT COMMITTEE
It is considered that these attacks , whilst
they certainly frustrated an attack on the convoy or its escorts
were insufficiently close to inflict damage. From the narrative
and track chart it seems likely that SPEEDWELL's depth charges
were set too deep whilst MARNE’s attack appears to have missed
astern. The result is assessed as ‘Insufficient evidence of
damage'.
18th June 1942
