AROUND THE WORLD
Anti-submarine Indicator Loop stations in the United States
Peaks Island/Fort Elizabeth
Drawing by Gerry Butler
Loop receiving stations, as they
were known, were operated by the United States Navy. We have most
information on those along the North Eastern coast. Added information on
other installations would be appreciated. Defence of the harbors
however began 300 years earlier when Governor Winthrop authorised earthwork
fortifications to protect Boston against attack by sea (May 1632). This
fort was known as Fort Hill. It was later demolished an eventually rebuilt
as Fort William in 1673 This report draws heavily on a review
of station logs and war diaries for Naval Unit 1F (Peaks Island and Fort
Williams) made by
Dave Pierson at National Archives and Records Administration
(NARA), Trapelo Road, Waltham, Massachusetts in April 2000. These logs
and diaries were handwritten and typically cover two to three days per
page. They were all stamped ‘secret’ but are now declassified. The other
Naval Units' records await a later trip to Waltham.
The following gives some of the
day-to-day details at Peaks Island and Fort Williams loop stations from
1942 to 1944.
This information has been extracted from the Waltham, Massachusetts archives by
Dave Pierson. He can be contacted at:
davep@quik.com In April 1942 a site was selected
for the station. Possible sites included Fort Williams, "Smiths" on Peaks
Island; the 8th Maine Regimental Property (on Peaks); the Smith
House – opposite head of beach, 600 feet from tail cables; the knoll to
the east; west end of beach – 800 feet to tail cables. The USN decided
against Fort Williams for several reasons, notably - because of the greater
distance to the loops and tails; the need to add extra ‘tails’, the proximity
to the heavy gun emplacements (vibrations upset galvanometers); and the
risk of damage to the landing tails by the rocky shore. Eventually, the
Peak Island site was chosen – a cottage about 1 mile from the gun emplacements.
A quick lick of paint and then they moved in. The officers were stationed
in luxury at Oak Cottage, about 1¼ miles from the loop station. Two loops - initially called 1 and
2 - were laid by the army. As they had cable laying ships for the controlled
minefields in the area, this proved ideal. These loops were soon renamed
Affirm and Baker. They were both of the three-legged design (see Indicator
Loop technical page for details). Affirm consisted of three 3000 yard legs,
spaced 120 yards apart (3000, 120 + 120); Baker was a 4000, 160 + 160 loop
arrangement. Both were in water 15 fathoms deep. The tails were connected
to the loop station on 21st April 1942.
A week later (27 April) the electrical
equipment was installed in the loop room. It consisted of General Electric
Flux Meters (galvanometers) and a teletype machine. Testing then began.
What appears to be the first magnetic signature recorded was that of the
37,000 ton battleship USS North Carolina, just before she headed
off to the Atlantic to defend convoys against the German battleship Tirpitz.
Signatures of a cruiser and an aircraft carrier were recorded and all were
mounted on cards for reference and training purposes (see below). Two Lights to Baileys Island Loops
Taken together these gave an inner
ring of loops from Fort Williams to Peaks Island to Long Island, and an
outer ring from Two Lights to Bailey's Island. The inner ring was
also fitted with moored and radio linked-moored hydrophones. All
other navigable passages into Portland Harbor were closed with Anti Submarine
Nets for the duration of WWII.
More problems
On September 22nd, the
station was officially changed in status from Naval Signal Station No.
6 to a loop receiving station (USN LRS). All of the signalling equipment
thus had to be returned. This included 150 flags, one 12" searchlight,
one rheostat and one typewriter. In return, four rifles were sent over
to be "left loaded in strategic positions" near the loop station and the
petty officer was henceforth required to carry a pistol.
Shift to Fort Williams
By 8th December the Navy
decided that the cables were not functioning properly and relaid Affirm
with ‘slack lay’ to reduce the pertubations caused from laying a cable
too taut. The following lengths of Type 111 cable (in yards) were added
to the cables: Affirm – inner 135, middle 300, outer 450. To Baker, 150,
135, 135 was added respectively. This seemed to improve sensitivity and
they were now getting between 200 lines (Affirm) and 400 lines (Baker)
although magnetic interference from minesweepers (up to 8 miles away) was
creating havoc particularly with Baker’s recorders. Interference continued
to be a source of problems at the start of 1943. Affirm was recovered and
relaid nearby as loop ‘Able’. The army cables near Baker’s tail cable made
balancing (centring) difficult. Various transmitters – such as those of
the Harbor Entrance Control Post produced continual interference particularly
on the 2150 kHz frequency. This caused fuses to blow in the resistor balancing
box. On April 3rd 1943, representatives of the NLDF (?) found
that the public power supply was improperly grounded and fixed that easily.
However all they could do about electrical storms and the Northern Lights
was to install double pole, double throw switches. This seemed to do the
trick. Things were looking up – the American Legion sent over a gift of
31 phonograph records.
Monthly reports
Severe magnetic disturbances continued
to cause problems at all stations. A comparison of signatures between Fort
Williams, Bailey Island and Cape Elizabeth during mid to late 1944 confirmed
that atmospheric disturbances were to blame. But by then, it didn’t matter
much.
On July 5, 1944, U-233, a German
Type-X1B minelayer (90 m long) was sunk by aircraft and USN destroyer escorts
USS Baker and USS Thomas after a 9 minute battle. It crawled its way 100
miles down the coast and entered Casco Bay where it finally sank. However,
no loop recording was made. As the threat from German U-Boats waned, the
loop stations were gradually wound down. What remains of them today is
not known. But we’re trying to find out. If you have any idea, please contact
Richard
Walding or Dave Pierson.
* Text reference in paragraph 1:
Butler, Gerald (2000). The Military History of Boston's Harbor Islands.
Arcadia Publishing, 2 Cumberland St Charleston, SC 29401 USA. 128 pages,
cost US$17 + US$9 p&h (overseas). Email: sales@arcadiapublishing.com.
Web address www.arcadiapublishing.com.
A fascinating book - 250 photos from 1860 onwards.
Additional information, including a chart
fo the loop locations, may be found in: And from the Gift Shop at
If
you worked there or have any feedback please contact me:
Email: Dr. Richard Walding (waldingr49@yahoo.com.au)
Research Fellow - School of Science
Griffith University
Home Phone: 61 (0)7 32064976
69 Summit Street, Sheldon, Q, 4157, Australia
LINKS TO SOME OF MY LOOP PAGES:
WW2 comes to Casco Bay
The United States entered the war
after the Japanese attack on Pearl Harbor, December 7, 1941. The next day,
the old coast defense guns at Fort Williams in Cape Elizabeth, Casco Bay,
Maine were test fired. The concussion of the firing blew the doors out
of four recently constructed garages near the battery. The Coast Artillery
quickly moved out its mobile artillery to Biddeford Pool and Popham Beach
to temporarily extend the defenses of the harbor. By April 1942, the US
Navy installed anti-submarine nets and the highly secret anti-submarine
indicator loops at all the entrances to the harbor (the indicator loop
technology was developed by the Royal Navy in WWI and modified by the USN
in the 1930s to suit local needs). The Coast Artillery planted mine fields
in the main channels into Portland Harbor. Coast Guard patrolled the waterfront,
and troops were sent to Maine to guard vital highway and railroad bridges,
such as the Grand Trunk Railroad bridge at Yarmouth Junction. The Navy
was a popular branch of the service in Maine, and a mass enlistment in
Navy took place in Portland June 7, 1942.
Peaks Island/Fort Williams Loop
Station
An outer ring of loops was established
from Bailey's Island to Two Lights.
The receiving station appears to
have been on Baileys. Three loops were laid, each covering roughly
2 miles, shown as loop E, F and G. This gave some localization of
the contact, and matched the capabilities of the loop technology.
USS New Jersey
This recording was made by S. Handler
at the Fort Williams Loop Receiving Station on 20th December
1943 when USS New Jersey, (shown above), under the command of Capt.
Carl Holden, made an inward crossing of Able Loop at 11.52 am. Visibility
was high that morning (10 mi). The galvanometer being used was the GE Type
OS-2, Serial No. #19, set at a shunt ratio of 125:1 and the sensitivity
control set at zero. An injected voltage of 0.06 V to the Right was used
for centring. The graph has the characteristic pattern of two crests and
one trough, with the trough height (31 "lines" of flux) about twice that
of the crests (18 "lines"). A "line" of flux is determined by the sensitivity
control setting on the amplifier. In this case, the setting was zero which
meant the sensitivity was left at it's base rate of 1000 lines per mm.
The peak-to-peak distance is 18 + 31 (= 49 lines) which corresponds to
49000 Maxwells of magnetic flux linkage. This can give operators a idea
of the size of the boat. For example, a 250 ton undegaussed U-Boat has
a magnetic flux of 40000 Maxwells at 10 fathoms at this latitude. The speed
can be calculated from the vertical lines (1 cm apart) and 1 cm = 1 minute.
From start to finish took the 888 ft long USS New Jersey six minutes
which corresponds to about 1.5 knots, assuming the loops are each 150 yards
wide. Two weeks later, New Jersey headed off to it's first naval
engagement - in the Pacific Theatre.
Staffing
In mid-May (1942), six men arrived
at the station to begin duties. The USN believed that one man was sufficient
per four-hour shift as there was little traffic over the loops. Six raincoats
were ordered (one mile to the barracks) and typhoid shots were given all
round. The first bit of excitement was on the 11th May when
a crossing was recorded in thick fog where no visual sighting could be
made. The second was three weeks later (3rd June) when the station
went on submarine alert. But it was just a false crossing caused by interference.
To top it off, that afternoon a bottle of mucilage and a stapler were received
in good condition, followed soon after by two pistols, holsters and 144
cartridges. But it wasn’t all take – there was give. Three left-over cans
of Benjamin Moore paint were given back and the army carried them away.
By 1st June 1942, the
operators were still having difficulty with signals from Baker and one
of the operators tinkered with it to get it working. The repairman warned
the operators "don’t do that". However, both recorders still proved erratic.
Whenever the bay was swept for mines the recorders were disconnected so
as not to blow their fuses. On June 22, 1942 a German U-Boat was suspected
of making an inward crossing but due to faults in the other loop, it was
not detected on its way out. The fault turned out to be from a loose terminals
due to the continual doing/undoing so on the 27th July (1942)
a knife switch was installed. A litany of other problems were reported
– paper jams in recorders, all three recorders unsatisfactory, sensitivity
problems with galvanometers, telephone problems, teletype line down, clock
not working. One fluxmeter – the OS-50 – was found to have a resistor in
the amplifying circuit that heated up causing unsteadiness in the recorder
preventing the needle from centring. The flux meters used were labelled
OS-02-09 (on Able), OS-0-51 (on Baker). OS-50 became the spare. The amplifier
attenuation settings were usually 1:1 or 1:5. In cases where sensitivity
was low (from a weak signal), the ratio was changed to 1:125.
The first repairs to the cables
were made on 26th October. A break was found in the centre leg
of Affirm and when this was repaired and relaid, the recordings improved.
However, the army blasting continued, and the loop operators had to keep
turning the flux meters off. This was hardly good harbor defence so the
USN decided to relocate the loop station to Fort Williams. On 9th
November, USCG Pequot spliced the tail cables to the new location. Mr Simpson
and Lt Sigafoos from BuShips (Bureau of Ships) inspected the station and
approved it as ready for the grand opening. The new loop room was 8’ square
– hardly enough to swing a cat. Seven men were stationed there.
They were now recording monthly
crossings of about 365 ships across Able and 37 over Baker. Also done monthly
were loop resistance checks. The resistance – in ohms – were as follows:
Loop Able B-R 19.71, B-W 19.18, R-W 19.84; Loop Baker 28.03, 27.79, 27.63.
Recall that Baker loop was about 1/3 longer than Able, hence the increased
resistance. The sensitivity readings varied between 77 and 240 for Able
and 164 to 455 for Baker which were quite acceptable and gave good, clear
signatures. As usual, all recordings were burnt at the end of each month
(ie March recordings burnt at the end of May).
SOURCE MATERIAL
NARA
Naval Records
National Archives and Records Administration
Records of Naval Districts and Shore Establishments (Record Group 181)
1784-0981
Textual Records (in Boston): Station
logs, 1942-45. Operation (loop signature) logs, 1942-45.
Textual Records (in Boston): Station
logs, 1944-45. Weekly war diaries, 1942-45.
Textual Records (in Boston): General
correspondence, 1941-44. War diaries, 1942-43. Station logs, 1942-44. Operation
logs, 1942-43.
Textual Records (in Boston): Station
logs, 1944.
OUR THANK YOU
We appreciate the assistance of
the NARA archivists in making the Naval Unit files available for review.
Portland Head Light
and Fort Williams
Kenneth E Thompson Jr
The Thompson Group
55 Vannah Ave
PO Box 3897
Portland, ME
04104
Portland Head Light Museum
Cape Elizabeth,
ME
SOME USN INDICATOR LOOP LINKS