The Welfreighter was a Second World War British midget submarine

Midget submarine

A midget submarine is any submarine under 150 tons, typically operated by a crew of one or two but sometimes up to 6 or 8, with little or no on-board living accommodation...

 developed by the Special Operations Executive

Special Operations Executive

The Special Operations Executive was a World War II organisation of the United Kingdom. It was officially formed by Prime Minister Winston Churchill and Minister of Economic Warfare Hugh Dalton on 22 July 1940, to conduct guerrilla warfare against the Axis powers and to instruct and aid local...

 (SOE) for the purpose of landing and supplying agents behind enemy lines. It only saw action once and was never particularly successful.

Design

After the success of the X class midget submarines

X class submarine

The X class was a World War II midget submarine class built for the Royal Navy during 1943–44.Known individually as X-Craft, the vessels were designed to be towed to their intended area of operations by a full-size 'mother' submarine - - with a passage crew on board, the operational crew...

, an attempt was made by SOE's technical division, Inter Services Research Bureau (ISRB) under the command of Lt. Colonel John Dolphin

John Dolphin

John Robert Vernon Dolphin CBE was a British engineer and inventor who became the Commanding Officer of the top secret Second World War Special Operations Executive 'Station IX' where specialist military equipment was developed. During his time there his inventions included the Welman midget...

 to design a submersible craft for covert missions. These would include the landing and supply of agents behind enemy lines, intelligence gathering work off hostile coastlines, and delivering explosive depth charge

Depth charge

A depth charge is an anti-submarine warfare weapon intended to destroy or cripple a target submarine by the shock of exploding near it. Most use explosives and a fuze set to go off at a preselected depth in the ocean. Depth charges can be dropped by either surface ships, patrol aircraft, or from...

s to enemy shipping routes. This design became the Welfreighter. It was intended that the Welfreighter could travel surfaced by night towards an enemy-held coastline, submerging as and when necessary to avoid detection. The special agents would then be disembarked and go ashore along with their equipment, stored in the special containers. The Welfreighter would then sail out to sea and submerge itself to wait until the next night. At a pre-arranged time, or upon receiving a sound signal from the landing party (made by a mechanical device) it would surface again and pick up the agents, before heading out to sea either to rendezvous with a larger surface vessel or return to base under its own power.

The initial concept was a true miniature submarine which could from a distance be mistaken for a conventional motor boat and which could hold two agents along with its crew of two men, and which could also carry up to one ton of supplies in sealed containers. The designed range was to be up to 600 miles (965.6 km) on the surface, with a range of 200 miles (321.9 km) at speeds of up to 8 knots (15.7 km/h). While submerged it was to be capable of diving to a depth of 130 feet (39.6 m) and travelling up to 40 miles (64.4 km) underwater.

Design work began towards the end of 1942 with the building of a 1/4 scale model which was used for tests in an experimental tank at Vickers

Vickers

Vickers was a famous name in British engineering that existed through many companies from 1828 until 1999.-Early history:Vickers was formed in Sheffield as a steel foundry by the miller Edward Vickers and his father-in-law George Naylor in 1828. Naylor was a partner in the foundry Naylor &...

' plant at St. Albans. By February 1943 the tests had produced several alterations to the original design including modifications to the hull form to make it stable under tow at speeds of 10 knots (19.6 km/h) - 15 knots (29.4 km/h).

Prototypes

Following the model tests, permission was granted for the construction of a full size prototype at the SOE establishment known as The Frythe

The Frythe

The Frythe is a country house set in its own grounds in rural Hertfordshire, just outside the village of Welwyn, about 30 miles north of London....

near Welwyn Garden City

Welwyn Garden City

-Economy:Ever since its inception as garden city, Welwyn Garden City has attracted a strong commercial base with several designated employment areas. Among the companies trading in the town are:*Air Link Systems*Baxter*British Lead Mills*Carl Zeiss...

.

The first prototype had little resemblance to the later versions. When launched at Staines

Staines

Staines is a Thames-side town in the Spelthorne borough of Surrey and Greater London Urban Area, as well as the London Commuter Belt of South East England. It is a suburban development within the western bounds of the M25 motorway and located 17 miles west south-west of Charing Cross in...

 in May 1943 it permitted further tests but showed flaws in that it was not stable under tow at speeds over 7 knots (13.7 km/h) and lacked freeboard

Freeboard (nautical)

In sailing and boating, freeboardmeans the distance from the waterline to the upper deck level, measured at the lowest point of sheer where water can enter the boat or ship...

. A second prototype was begun in June and was tested throughout the autumn and winter.

A third prototype was begun in September 1943. Its surface range - 1000 miles (1,609.3 km) - exceeded the specification, but at the expense of reducing the storage capacity by 240 pounds (108.9 kg). Its speed was less than the specification, at 6 knots (11.8 km/h) maximum while surfaced, with a mere 2 knots (3.9 km/h) submerged. It did however perform satisfactorily when pressure tested to a depth of 130 feet (39.6 m).

Production

In early 1944 a specification for a final Mk III version was proposed by SOE, which eventually entered series production. The range was now specified as 1000 miles (1,609.3 km), with an additional 1000 miles (1,609.3 km) using disposable tanks (which however meant a loss of the diving capability). A further 600 miles (965.6 km) could be added if part of the storage capacity was used. The accommodation had also been enlarged; as well as the two crewmen, 4 passengers could be carried on short voyages, or 3 for longer trips. The cargo capacity had also been enhanced to enable between 1.5 and 2 tons to be carried. Underwater endurance had also been augmented, the craft now being capable of supporting 6 persons for up to 40 hours submerged. Finally, surface speed had been increased to 5.5 knots (10.8 km/h) cruising speed, or 7 knots (13.7 km/h) maximum. Even the electric propulsion was upgraded: it could deliver 2-3 knots.

By now it was apparent that it was unlikely that the Welfreighter would be needed in Europe, therefore consideration was given to its use in the Far East.

Due to the urgency of production it was not possible to create a dedicated factory. As had happened with the Welman submarine

Welman submarine

The Welman submarine was a Second World War one-man British midget submarine developed by the Special Operations Executive. It only saw action once and was never particularly successful.-Design:...

 the year before, production was contracted out to specialised engineering firms already engaged in production of war material. In the spring of 1944 the Letchworth

Letchworth

Letchworth Garden City, commonly known as Letchworth, is a town and civil parish in Hertfordshire, England. The town's name is taken from one of the three villages it surrounded - all of which featured in the Domesday Book. The land used was first purchased by Quakers who had intended to farm the...

 company of Shelvoke and Drewry

Shelvoke and Drewry

Shelvoke & Drewry was a British manufacturer of specialised commercial vehicles, now defunct. It was best known for its innovative waste collection vehicles, which were once the preferred choice of municipal authorities in the UK...

 Ltd. was awarded a contract to produce Welfreighters. By early September an order for up to 34 Welfreighters was placed for delivery as soon as possible after October 1. The company had no experience of ship construction, and was 75 miles (120.7 km) from the sea. Security surrounding the production of the Welfreighter was tight, and few non-vetted

Vetting

Vetting is a process of examination and evaluation, generally referring to performing a background check on someone before offering him or her employment, conferring an award, etc...

 employees knew the truth until after the end of the war.

Completed craft were transported at night under canvas covers to Station IX at Welwyn, where they were fitted out, the compass and periscope and secret equipment fitted. The craft were then balanced, trimmed, and pressure tested in the establishment's water tank. They were then transported onwards to Fishguard

Fishguard

Fishguard is a coastal town in Pembrokeshire, south-west Wales, with a population of 3,300 . The community of Fishguard and Goodwick had a population of 5043 at the 2001 census....

 in Wales, for sea trials.

Appearance

The Welfreighter outwardly resembled a conventional 37 feet (11.3 m) motor boat. While surfaced it was propelled by a Gardner 4LW 44 hp diesel

Diesel engine

A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...

 omnibus engine driving a 4-bladed propeller, while underwater propulsion was provided by two 2 hp electric motors, driving a pair of small propellers. Two "masts" on the craft's foredeck housed a Barr and Stroude periscope

Periscope

A periscope is an instrument for observation from a concealed position. In its simplest form it consists of a tube with mirrors at each end set parallel to each other at a 45-degree angle....

 and a magnetic compass. A dummy mast and sail could be attached to these masts to help disguise the craft as a fishing smack

Smack (ship)

A smack was a traditional fishing boat used off the coast of England and the Atlantic coast of America for most of the 19th century, and even in small numbers up to the Second World War. It was originally a cutter rigged sailing boat until about 1865, when the smacks became so large that cutter...

. The foredeck was raised up to give some headroom inside the craft, and was fitted with small square viewports.

To the rear of the main structure was a raised deck, beneath which were housed 6 high pressure air cylinders. To the rear of this area was a cargo well, fitted at the stern with a drop-down tailgate. This could house seven cylindrical drums of cargo. Carefully loaded so as to give a slight positive buoyancy, these drums could hold equipment for use by agents or saboteurs and could be floated out through the tailgate and towed ashore by agents, either swimming or using an inflatable boat.

Each Welfreighter was manned by a Sub Lieutenant RNVR as Commander, and a Naval Engine Room Artificer (ERA

ERA

Era refers to a long period of historyERA or Era may also refer to:In games and sports:* Earned run average, a baseball statistic* Era Online, a computer game* English Racing Automobiles, a manufacturer of racing carsIn music:...

) or Army mechanic (REME

Reme

Reme may refer to:*Rəmə, Azerbaijan*Royal Electrical and Mechanical Engineers...

). Up to four special agents could travel as passengers, although two would be more usual. These would commonly be Army personnel, who would be expected to assist with handling the craft while on the surface.

Europe

Before the Welfreighter became properly operational the secret war in Europe was nearly over. In late 1944 plans were discussed to deploy the craft to the Adriatic, to assist operations in the Balkans

Balkans

The Balkans is a geopolitical and cultural region of southeastern Europe...

, where SOE was involved in supporting partisan

Partisan (military)

A partisan is a member of an irregular military force formed to oppose control of an area by a foreign power or by an army of occupation by some kind of insurgent activity...

s in northern Greece, Albania, and what was later to become Yugoslavia

Yugoslavia

Yugoslavia refers to three political entities that existed successively on the western part of the Balkans during most of the 20th century....

.

It was also suggested that Welfreighters could be used to plant mines in the entrances to German ports, but this was dropped when it was demonstrated that a suitable charge would have to weigh over 224 pounds (101.6 kg), which would be too much for the craft's buoyancy and trim.

Trained Welfreighter crews were ready for operations through the autumn of 1944, but neither Combined Operations HQ or SOE ever required anything of them.

Far East

Two Welfreighters were shipped to Fremantle

Fremantle, Western Australia

Fremantle is a city in Western Australia, located at the mouth of the Swan River. Fremantle Harbour serves as the port of Perth, the state capital. Fremantle was the first area settled by the Swan River colonists in 1829...

, Australia, in late 1944, to become part of the clandestine Services Reconnaissance Department

Services Reconnaissance Department

The Services Reconnaissance Department , also known as Inter-Allied Services Department , Special Operations Australia and Section A, Allied Intelligence Bureau was an Australian military intelligence and special reconnaissance unit, during World War II.Authorised by General Thomas Blamey in March...

 (commonly known as Z Special Unit

Z Special Unit

Z Special Unit was a joint Allied special forces unit formed during the Second World War to operate behind Japanese lines in South East Asia...

). Extensive trials were conducted, including towing trials and exercises using high powered motor launches and Motor Torpedo Boat

Motor Torpedo Boat

Motor Torpedo Boat was the name given to fast torpedo boats by the Royal Navy, and the Royal Canadian Navy.The capitalised term is generally used for the Royal Navy boats and abbreviated to "MTB"...

s.

However, the project started to lose momentum by April 1945. Douglas MacArthur

Douglas MacArthur

General of the Army Douglas MacArthur was an American general and field marshal of the Philippine Army. He was a Chief of Staff of the United States Army during the 1930s and played a prominent role in the Pacific theater during World War II. He received the Medal of Honor for his service in the...

, the Supreme Commander in the South West Pacific Area (SWPAC), under whose command fell all Allied war effort in the Pacific war, distrusted the Welfreighter's concept, and his Naval advisors refused to consider them useful to the war effort.