Source: ADM 199/184
Operation DM4 6.10.39
OPERATION DM4
From: Vice
Admiral, Dover
Date: 3rd October 1939
To be carried
out, weather permitting, on Friday 6th October 1939. Zero
hour 1545 (Subject to confirmation).
Ships
taking part
Minelayers: Hampton, Shepperton
Destroyers: As detailed by Captain (D) 19
Minesweepers: Available ships of 5th M/S Flotilla
Surveying ship: Franklin
Mines to
be laid
Hampton will lay groups I1, I2, I3 and I4
Shepperton will lay groups I5 and I6
Embarkation
Mines to be
placed alongside the ships at 0700 on Thursday 5th
October.
Depth
adjustment
Group |
No. of Units |
Depth Reel |
Chain |
Adjustment |
I1 |
102 |
70ft |
14ft |
Remove 9 ft chain |
I2 |
10 |
60ft |
14ft |
Remove 4
ft chain |
I3 |
10 |
60ft |
14ft |
Remove 4
ft chain |
I4 |
52 |
70ft |
14ft |
Remove 7
ft chain |
I5 |
220 |
50ft |
14ft |
Remove 6
ft chain |
I6 |
44 |
70ft |
14ft |
Remove 5
ft chain |
Procedure
Should it be
necessary to postpone the operation the new zero hour will be
signalled by Vice Admiral, Dover. After minelayers have left
harbour, SO Minelayers is to use his discretion as to postponing the
operation should he consider this necessary on account of weather or
for any other reason.
Minesweeping
Minesweepers
are to leave harbour in time to sweep over line I before zero hour.
The depth of the sweep is to be 3 fathoms. When the minelayers have
passed the Varne a skimming sweep over the mines just laid between
the Searched Channel and the Varne is to be carried out at a depth
of 35 feet below the Chart Datum.
Escort
Captain (D)
19 is to detail three destroyers to screen the minelayers during the
operation.
Leaving
Harbour
Destroyers
are to leave harbour before the Minelayers, SO Minelayers signalling
his intended time of departure. FRANKLIN is to leave harbour as
convenient for carrying out any necessary surveying work before
making a rendezvous with the Minelayers.
Method of
Laying
Line I will
be laid from West to East with breaks on the Varne and the Ridge.
Hampton will finish her lay on arrival at the Ridge. Shepperton
starting after the break. Mines will not be laid within 5 cables of
the NE Ridge Buoy.
Franklin will
lead Hampton onto the line and Shepperton will be stationed 2 ˝
cables on the Port beam of Hampton. On completion of her lay Hampton
is to disengage to starboard, increase speed and cross ahead of
Franklin from Starboard to Port. This manoeuvre should be carried
out as quickly as possible in order not to blank Franklin’s view of
fixing points more than necessary. A compromise may be necessary
between high speed and prevention of funnel smoke.
Laying
Signals
The Black
Flag will be worked by Franklin as in previous lays but, in view of
the breaks in laying, the pendants of the ship to lay will also be
flown at the yard-arm.
Spacing
Mines are to
be laid 150 feet apart.
Return to
Harbour
On completion
of laying, minelayers are to return to harbour independently. One
destroyer is to be ordered to return with Hampton.
B H Ramsay
Vice Admiral,
Dover