US NAVY BEACH JUMPER UNITS
FORMATION, TRAINING & EQUIPMENT
Beach Jumpers were US Navy special warfare units, which specialized in commando style operations, deception and misdirection to confuse the enemy. The Navy had active Beach Jumper units from 1943-1946 and 1951-1972. Their basic mission was “To assist and support the operating forces in the conduct of Tactical Cover and Deception in Naval Warfare”. To reach their goal, they learned to simulate very large amphibious landings with very few resources, of which crash boats became an essential part. Using specialized deception equipment, a few dozen Beach Jumpers could make the enemy believe they were a large amphibious landing force, when in fact the actual assault force would usually attack many miles away.
The initial announcement to naval personnel stated “The Navy is requesting volunteers for prolonged, hazardous, distant duty for a secret project”. The first group of 15 recruits reported to the Amphibious Training Base at Camp Bradford, Virginia in March 1943, and formed Beach Jumper Unit 1 (BJU-1). They were housed in tents on the perimeter of the base to try to keep them segregated from other units based there. Training continued at the base until December 1943, when it was moved to the isolated Advanced Amphibious Training Base at Ocracoke Island, North Carolina where they carried out full-scale exercises.
The volunteers were taught seamanship, boat-handling, pyrotechnics, demolition, ordnance, gunnery and meteorology, and were trained to be able to operate in any of the boat’s crew positions. Weapons training covered everything from the standard issue pistol up to the 40mm cannon. They learned to use smoke generators and how to use smoke screens. All together this package of deceptive skills was put together to simulate an amphibious assault.
Initially they were assigned just ten 63ft Aircraft Rescue Boats powered by Hall-Scott engines. It is unclear how the 16 model 168 Packard powered 63ft Aircraft Rescue Boats ordered in 1942 fit into this group but it seems obvious that they were intended for “special ops”. Each crew totaled seven, just one less than a standard crash boat crew but certainly with a specialized skill set.
Deception gear on the BJU craft consisted of a multi-component audio transmission system known as a “Heater” which took six men to carry. It consisted of two “Presto” disc wire-recorders – using glass discs similar to 78 rpm records on acetate bases. The amplifier was 5-phase with a 1000-watt horn speaker with generators for power installed in the boat to both record and emit pre-recorded sounds of amphibious landings. Sound effects were either recorded in the harbour area of ship and boat activities or on army training grounds of tank engines etc. Sound tests were carried out which showed that the acoustic deception was most effective at a distance of 2000 feet from the target. Later raids in the Mediterranean put the Beach Jumpers that close to the enemy shore batteries.
Electronic deception was achieved by using jammers i.e. transmitters which would drown out the normal radar echo. In simple terms – normally a target would appear as a vertical spike on the radar, but by generating random noise (jamming) on the radar frequency the real target would be lost in a multitude of false echoes known as “grass”. This became one of the Beach Jumpers main deception techniques. There were two basic types of jamming, Spot or Barrage but “Barrage” jamming was the general broad frequency jamming method. The transmitters were pre-tuned evenly to cover all the known enemy frequency bands so blocking as many as possible. Operators were not needed for this method. By late 1944 the Beach Jumpers had several “Jammer Transmitters” to use.
The radar deception illusion was enhanced by another type of deceptive technique – radio countermeasures or communications deception, especially manipulative deception. This entailed the transmission, in the clear, of a scripted dummy voice or code traffic simulating actual assault force communications. Beach Jumper specialists used this to fool the Germans and the Japanese into believing that, rather than small boats operating offshore, they were a large amphibious force preparing to launch assault troops in landing craft; that they were, in the real attacking force. Operations were executed to a pre-determined script, which helped to make the deception quite realistic. False signals, radar reflections, smoke screens, and sound effects were timed so that they gave the impression the small BJU force was a much larger enemy assault force.
When deployed on missions, Beach Jumper Units were frequently deployed with PT boats and British crash boats. I have not seen any documentation indicating that USAAF crash boats participated in these composite units.
OPERATION HUSKY – INVASION OF SICILY
As a pre-requisite for the operation Allied Forces seized the small island of Pantelleria. In preparation for the invasion BJU crews prepared and tested their equipment and loaded it aboard the ARBs. Speakers for the “Heaters” were swivel mounted on the sterns of the boats so that they could be turned towards the beach no matter what direction the boat was travelling. The electric generators were set up with the wire recorders in the cockpit. To simulate 20mm gunfire, roman candles were mounted on pieces of 2 x 4 tlumber nailed in an “X” shape, with jury rigged pyrotechnics – these were lit and floated off into the sea from the ARBs.
At 10:00PM on July 11, 1943 the British boat ARB-39 positioned 1000 yards ahead of British 63 ft boats 39,48,49 and 69, was laying a thick smoke-screen as PT-213 closed the beach firing all its weapons, and then circled back out to sea behind the smoke screen. The sound boats ran up and down the coastline playing their pre-recorded “invasion” sound effect recordings and sending out phoney inter-ship messages, the decoys creating the effect of an armada of large vessels standing offshore. ARB-39 was laying more smoke pots when suddenly they were caught in the beam of a searchlight from Cape San Marco – so they moved away but later returned at high speed to fire rockets at the beach.
The deception had worked as the coastal defenses had opened up on the imaginary fleet. On their return, orders were received to continue the deception the following day, but this time combining the theatrical deception with an electronic package. The next day the BJU crews intermittently jammed the known radar frequencies, while others sent out scripted radio signals between the landing craft of the imaginary invasion force.
The success of the mission was undeniable. German news reported on July 13th that their forces had repelled a landing attempt between Sciacca and Mazzara de Vallo. The few weeks after this operation were spent conducting coastal patrols before returning to Bizerte. After WW II, captured documents and reports from prisoners proved that the date and scale of the landings had been a big surprise, and that an entire German reserve division had been held in place because of the deception tactics.
Beach Jumper Units, often combining U.S, and British boats, were active in the Mediterranean during WW II, including OPERATION AVALANCHE, in the Gulf of Gaeta where they captured 90 German soldiers at a radar installation. They also operated out of the island of Vis, off the coast of Yugoslavia, out of which they captured the island of Solta and its German garrison. They also participated in OPERATION BRASSARD, the landing on Elba.
Prior to the Normandy invasion it was determined that we would not have the resources available to simultaneously invade southern France. Beach Jumpers were deployed in OPERATION ANVIL-DRAGOON to convince the Germans that we were planning to invade Southern France at the same time as the Normandy invasion. After the successful Normandy landing the Beach Jumpers were assigned to OPERATION BIGOT-ANVIL with the task of convincing the Germans that the Allies would leap-frog up the coast of Italy to Genoa, rather than landing in Southern France. This caused the Germans to withdraw troops from Southern France and shift them toward Genoa, thinning out the defenses in the Cannes -Toulon area of Southern France, making the invasion easier.
TORPEDO & MISSILE RECOVERY
At the end of WW II, many of the small craft operated by the US Navy were surplus. A significant number of these boats were disposed of in the Philppines as well as other overseas locations. Rescue boats in the US were auctioned off for either commercial or private use in the late 1940’s. However, a number of the boats were kept by the US Navy, and quite a few were either modified or converted for post-war weapons trials and test programs. The layout of the 63ft rescue boats lent itself to being easily adapted for three roles, torpedo recovery, noise measurement of submarines, and drone launchers. Finally, some were simply used as targets. Rescue boat numbers and prior service history of most of these boats has not been found.
From the late 1940s to the mid-1950s a number of the 63ft rescue boats were converted to the role of Torpedo Retriever. The boats were often referred to as TR or TRB, which could mean either Torpedo or Target Retriever Boat. When the technology advanced to missile development, the 63’ boats operated by the USAF were converted to Missile Retrievers
The first boats converted to be Torpedo Retrievers were the WW2 vintage Model 314 boats, as these had the engine amidships, the cockpit aft, and thus was the easiest design to convert to the new role. The following profile and plan were taken directly from the reprint of the Official 1960 edition of the Catalogue of Boats of the US Navy. Whereas the plan is accurate and shows the detail of the torpedo recovery ramps, the associated winches and the deck storage of the torpedoes, the profile lacks the same detail. The profile does not agree with the plan in several areas, but the main difference is in the portrayal of the superstructure, particularly the flying bridge. The few photographs available suggest that this part of the profile is inaccurate. The boats were re-powered with twin diesels – these most likely to have been Gray HN64 type (known to be used in similar conversions of former USAF Mk3 boats) or Detroit Diesel engines which were used in other boats converted for Noise Measuring Boats.
The early Torpedo Retrievers were based at several locations including the two US Navy Torpedo Testing facilities at Newport, Rhode Island and at Keyport, near Seattle, Washington. The latter base at Keyport was locally known as “Torpedo Town USA”. Other areas where the boats operated were at San Diego, California; Key West, Florida and Norfolk, Virginia; all connected with testing areas and naval facilities supporting our submarines. Torpedo retrievers were also stationed at Pearl Harbor in support of the ranges and submarines operating out of Hawaii.
Shortly after World War II the U.S. Navy began to deploy acoustic homing torpedoes on board submarines. These torpedoes were significantly different than those used during the war. The new torpedoes could dive deeper, change course, and steer themselves toward the target rather than just run in a straight line, or manoeuver according to a well-defined pattern like WW II torpedoes. World War II torpedoes, especially early in the war, were very poor performers, many said not much better than junk. These new torpedoes also had improved versions of the contact exploder. By 1948-49 it became apparent to the Navy that Keyport's torpedo range in Port Orchard Inlet was much too shallow to test the new deep diving, acoustic Anti-Submarine Warfare (ASW) weapons that were coming off the drawing boards. In response to this, a nationwide search began for a protected body of salt water suitable for testing the new torpedoes. As a result of this search, Keyport began to shift torpedo testing operations to Hood Canal and the deeper Dabob Bay. In late 1949 the Navy received official permission from the U.S. Army Corps of Engineers to use parts of Dabob Bay and Hood Canal for “non-explosive torpedo ranging.” During the period 1947-1950 there was little production or testing carried out at Keyport, but as the Korean War started, during 1951 the facility was back again in full use. The facility has had several name changes over the years from the US Naval Torpedo Station in 1930, through when it was combined with the Naval Armament Depot at nearby Bangor in 1950 and became the US Naval Ordnance Depot Puget Sound. By 1978 it was apparent that the NTS role in undersea technology was no longer limited to torpedoes, so the name was again changed to NUWES (Naval Undersea Warfare Engineering Station), and later to NUWC (Naval Undersea Warfare Center).
From the dates of the boats being transferred to the Navy and since several were subsequently based at the Naval Ordnance Section at Key West, it is probable that they replaced all or most of the WWII era boats in service at the base, and included in that list would be those craft depicted below. Photos of the Mk3 boats converted to US Navy Torpedo Retrievers are also not very clear, but it appears that the conversions, were similar to the Mk2 boats with the flying bridge being cut down and shortened, and the gun tubs were removed. The conversion aft of the engine room was similar but made that much easier as the Mk3 boats already had a transom gate, which was easily modified for the recovery of missiles or later for torpedoes when in US Navy Service.
USAF Target Boat a.k.a. SEPTAR
(Self Propelled Radio Controlled Targets)
In the early 1950’s the USAF ordered replacement boats (Mk2) for their inherited WW II models and in the mid 1950’s a program of construction for the USAF Mk3 boats began. Several of these post-war built boats were subsequently converted and re-designated as Missile Retrievers (MR) by the USAF. (See Mk3 section for details). Subsequently a number of the Mk3 boats were transferred to the US Navy for further use, and again were either converted or re-converted for use as Torpedo Retrievers. The actual dates of conversion and service of the Missile Retrievers is not known. The USAF also converted some of the boats to missile targets and drone launchers.
SEPTAR, another view
Profile of Drone Launcher