Emergency Radio Room

The emergency radio room was located on the main deck aft and provided for emergency communications with the outside world in the event of the destruction of the main radio room forward.  Originally the main piece of equipment in this space was the TCS radio transmitter and receiver.  Also on display here aboard the SLATER, is the High Frequency Radio Direction Finder (Huff/Duff).  The Huff/Duff was developed to intercept German radio transmissions from U-boats.  The equipment, originally developed by the British, played an important role in the detection and location of German submarines during the Battle of the Atlantic.  

Generally an effort was made to fit at least one ship in every escort division with Huff/Duff. As originally built SLATER was not fitted with Huff/Duff. However, because it was such a critical piece of destroyer escort history, when the opportunity came to acquire the unit, it was incorporated into the historical display.

Emergency equipment in the Emergency Radio Room aboard USS SLATER.

World War II "Huff Duffers"

 

Huff/Duff aboard USS SLATER DE-766.

 

Huff/Duff operator aboard HMCS SWANSEA

By: James Saladin, RM1, USS JACCARD (DE355)

HUFF DUFFERS was a term sometimes used to identify special 3-man crews of radiomen aboard specific warships, operating direction finding equipment, to help locate enemy German submarines. The acronym was derived from the “HF/DF” identity of the equipment.

During the early years of WWII in the Atlantic, German “Unterseeboots” (U-boats) were sinking Allied ships faster than replacements could be built. In fact, a few sinkings took place just off the East coast. U-boats were also operating in “wolf packs”, which added to the destruction. A means of quickly locating these enemy subs was given high priority.


Huff/Duff operator aboard HMCS SWANSEA

 

American and British engineers working together, developed new and sophisticated equipment for rapidly pinpointing radio transmitting German submarines; using a new High Frequency Radio Direction Finder, operating in the band of 1.5 to 30 Megacycles, now called Megahertz. It was in this frequency range that the enemy subs transmitted when surfaced at sea. The new top secret equipment was known as DAQ. Along with its specialized antenna system, the DAQ was installed primarily aboard DEs and Destroyers. The antenna array was installed aft of the ship’s stacks, about halfway to the fantail.

The antenna consisted of two crossed, rigid vertical diamond (rhombic-type) arrays, with a vertical sense antenna attached at the apex, and mounted on a mast about 25 feet tall, as I remember. Feed lines connected the antennas to the DAQ, normally located near CIC.

The DAQ married an AM receiver to a goniometer – a piece of equipment mounted just below the receiver. A revolving magnetic field surrounded the goniometer’s scope, which was about 7 or 8 inches in diameter. During radio reception, the amplified signal voltage was fed to the goniometer, producing a pattern on its scope resembling a two-bladed airplane propeller pointing in two directions, 180 degrees apart. Immediately, the DAQ operator rotated a ring on the scope containing cross hairs through the two propeller tips. By applying the received signal from the sense antenna, the two blades folded forming an arrow pointing in the direction of the received signal. Quickly, the operator scanned the calibration chart for the particular frequency being received to determine the direction accuracy. If the received signal strength was strong, and the image appeared clean on the scope, with no ragged edges, indicating a probable RF ground wave from a nearby sub, the operator grabbed the TBS radio remote handset, installed next to the DAQ and spoke, “BUZZ, BUZZ,” and gave the correct bearing to all ships, as well as his ship’s CIC. Since the time element was critical, we operators had previously been instructed to forego transmission permission from the bridge. In each convoy, at least two warships were equipped with the DAQ, stationed some distance apart for a better triangulation and would transmit each ship’s bearing of the sub’s signal. Triangulations would quickly pinpoint the enemy sub for whatever action might be needed.

Should the enemy sub’s signal be weak and show a ragged pattern on the scope, normally indicating a distant transmission, we would simply copy the signal (no typewriter, pencil and paper only!) and note the type of transmission–which we’ll get into later. The various sub’s CW signal speeds varied, but was normally around 12 words-per-minute which made for easy “stick” (pencil) copying.

The DAQ training facility was located at Casco Bay, Maine, probably early 1943, and my class may have been the first. There we became familiar with the DAQ equipment, and learned some supplemental CW codes employed by the Germans. They, of course, used international Morse code, but also used a number of umlaut characters. For instance, a number of alphabetical letters transmitted in Morse code would have a dash (“dah” in radiomen’s language) added to create an umlaut character. True umlauts are modified vowels; however, the Germans modified a number of consonants for specific submarine warfare purposes, such as identifying a sighting transmission; an attack transmission; a homing signal, possible for other U-boats to join up, and other conditions. I no longer remember what certain umlaut characters meant for specific purposes. A transmitted letter “L” in international Morse code would be “dot-dash-dot-dot,” or “dit-dah-dit-dit” in radiomen’s language. The added dash could only be applied to a select few international CW letters, otherwise adding it would represent a different alphabetical letter.

Each ship with a DAQ installed had to be “calibrated” before returning to service. This required the ship to anchor in open water while a small craft circled it and transmitted bearings to the ship on each of the numerous frequencies employed by the German subs. The calibrating crew included a radioman who came aboard and operated the DAQ, noting the small craft’s transmitted bearing against the DAQ’s reading. The calibrating vessel made a complete circle of the ship for each radio frequency the subs used, transmitting with minimal power for security reasons. Later, the ship’s DAQ crew developed operational charts, corrected for accuracy, because the ship’s superstructure affected the received signal’s bearing from certain quadrants by as much as 180 degrees. Any time the ship’s superstructure was modified, recalibration was necessary.

Potential DAQ operators attending the Casco Bay school were Radiomen 3rd Class, if I remember correctly. Toward the end of the training, 3-man crews were formed. And here is the good part: we were allowed to choose and form our own crews before reassignment. In many, if not most cases, this meant staying together as DAQ operators in the Atlantic, even when transferring among ships.

And now for a particular crew: Dale Evans and I, both Radiomen 3rd Class, transferred from the USS RODMAN (DD456), our first ship, to Casco Bay on March 17, 1943. Arriving the same day was Jack Thompson, from the USS EARLE (DD635), also a Radioman 3rd Class–a Navy classmate from Northwestern University. We were approved as a 3-man crew early on. Following completion of training, we were assigned to the USS CARMICK (DD493). Later, we were transferred to the USS COONER (DE172). On September 18, 1944 we boarded the USS JACCARD (DE355) for the rest of the war. Our duty aboard the USS JACCARD as DAQ operators was short lived, as we cleared the Panama Canal on October 27, 1944 en route to Hollandia, New Guinea to join Admiral Kincaid’s 7th Fleet. Our many months together as a HF/DF crew of Huff Duffers had come to an end; we now became regular Radiomen 2nd Class with a great crew of radiomen.

With the war over, we started counting home-going points. Thompson departed Subic Bay aboard the USS EDWARDS (DD619) for San Diego and discharge. I left Cavite, PI aboard the USS CRUX (AK115) for a nonstop, 26-day “turtle-crawl cruise” to San Francisco for discharge, sleeping on bare bunk springs with two blankets, two meals a day, and saltwater showers, but it didn’t matter – I was coming home! Dale Evans, who advanced to RM1 when I left the ship, stayed behind to complete his USN 6-year hitch. Of a Chief and eight radiomen aboard the USS JACCARD at the end of WWII, only Thompson and I are still living.

This article cannot end without returning to 1944 and an incident that occurred in the Atlantic – in late August, I believe. The USS COONER (DE172), along with many other warships, was escorting a huge convoy (97 ships we were told–ships everywhere) from the States to the Mediterranean, where we were attacked by German aircraft. We encountered foul weather and heavy seas somewhere beyond the halfway point. An unfortunate merchant ship in the convoy lost its screw and became dead in the water. We were ordered to stand by it, screen for enemy subs, and render whatever assistance we could. The next morning a decision was made to tow the stricken vessel, but after two failed attempts, we headed on to rejoin the convoy. But exactly where were we, and where was the convoy? Unable to take celestial readings, things could have been better. Our navigator asked the Huff Duffer on watch, Jack Thompson, if could we get a bearing on the convoy if radio silence were broken? With a positive probability, the DAQ receiver was tuned to the appropriate frequency and radio silence was broken. The Flag replied and the convoy’s bearing was obtained! But all was not well. The indicated bearing put the convoy almost in the opposite direction, which the skipper said was impossible. Going through the corrected DAQ frequency charts, one was selected that nearly matched the radio frequency used for our contact. Guess what? The chart revealed the bearing obtained had REVERSED SENSE!! The captain accepted the corrected bearing, the Quartermaster commenced drawing lines, engine RPM increased, and the next day we, again, began screening the convoy! The ol’ - no, the young HUFF DUFFERS had done their thing. We never learned the fate of that unfortunate merchant ship.

Continue Tour: Crew’s Head