HMS Swordfish was an experimental submarine

Submarine

A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...

 built for the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 before the First World War

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

 to meet the Navy's goal of an "overseas" submarine capable of 20 knots (10.9 m/s) on the surface. Diesel engine

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...

s of the period were unreliable and not very powerful so steam turbines were proposed instead to meet the RN's requirement. Swordfish proved to be slower than designed and unstable while surfacing, and consequently she was modified as an anti-submarine patrol vessel in 1917. She was paid off before the end of the war and sold for scrapping in 1922.

Design

HMS Swordfish was developed to meet a requirement of Royal Navy's Submarine Committee for a large submarine capable of operating with the fleet at a surfaced speed of 20 knots. Most of the earlier British submarines had been single-hulled

Submarine hull

The term light hull is used to describe the outer hull of a submarine, which houses the pressure hull, providing hydrodynamically efficient shape, but not holding pressure difference...

 vessels built by Vickers and the Navy was interested in evaluating other designs. Captain

Captain (naval)

Captain is the name most often given in English-speaking navies to the rank corresponding to command of the largest ships. The NATO rank code is OF-5, equivalent to an army full colonel....

 Roger Keyes, Inspecting Captain of Submarines, had previously served as naval attaché

Attaché

Attaché is a French term in diplomacy referring to a person who is assigned to the diplomatic or administrative staff of a higher placed person or another service or agency...

 in Italy and had kept abreast of Italian submarine developments, which notably included double-hulled submarines designed by Cesare Laurenti of Fiat-San Giorgio. Three boats of the S class

British S class submarine (1914)

The British S class submarine of 1914 were built by Scotts, Greenock just before World War I. The S class was based on an Italian design of the Laurenti boats.The design had ten internal bulkheads.Three vessels were constructed...

 were ordered first and Laurenti was invited to submit a design to meet the RN requirement.

Fiat-San Giorgio "was wary about using heavy oil [Diesel] engines and hesitated to guarantee the success of such engines of the power required. At the same time Laurenti prepared a design with geared steam turbines having a speed of 18 knots on a surface displacement of 856 tons." His design was modified by Scotts Shipbuilding and Engineering Company

Scotts Shipbuilding and Engineering Company

Scotts Shipbuilding and Engineering Company Limited, often referred to simply as Scotts, was a Scottish shipbuilding company based in Greenock on the River Clyde.- History :...

, Greenock

Greenock

Greenock is a town and administrative centre in the Inverclyde council area in United Kingdom, and a former burgh within the historic county of Renfrewshire, located in the west central Lowlands of Scotland...

, to include guns. Swordfish kept the same main dimensions as Laurenti's original design, but had a greater displacement and less endurance.

Description

Swordfish had an overall length of 231 foot, a beam

Beam (nautical)

The beam of a ship is its width at the widest point. Generally speaking, the wider the beam of a ship , the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position...

 of 22 inch, and a draught of 14 in 11 in (4.55 m). She displaced 932 long tons (947 t) on the surface and 1105 long tons (1,123 t) submerged. She had a partial double hull, which extended over 75% of her length. The upper portion of the double hull was controlled free-flooding while the rest was devoted to watertight 'baling flats', ballast

Ballast tank

A ballast tank is a compartment within a boat, ship or other floating structure that holds water.-History:The basic concept behind the ballast tank can be seen in many forms of aquatic life, such as the blowfish or argonaut octopus, and the concept has been invented and reinvented many times by...

 and fuel tanks. Her hull was divided into eight compartments by seven watertight bulkhead

Bulkhead (partition)

A bulkhead is an upright wall within the hull of a ship or within the fuselage of an airplane. Other kinds of partition elements within a ship are decks and deckheads.-Etymology:...

s.

Swordfishs diving depth and time are not known because the records from her sea trial

Sea trial

A sea trial is the testing phase of a watercraft . It is also referred to as a "shakedown cruise" by many naval personnel. It is usually the last phase of construction and takes place on open water, and can last from a few hours to many days.Sea trials are conducted to measure a vessel’s...

s have not survived. Shutting down her boiler, retracting the funnel and sealing the boiler uptake required about a minute and a quarter, which included switching over to the electric motors. In marked contrast to contemporary Vickers designs much attention was paid to safety arrangements, including her extensive subdivision. Indicator and telephone buoy

Buoy

A buoy is a floating device that can have many different purposes. It can be anchored or allowed to drift. The word, of Old French or Middle Dutch origin, is now most commonly in UK English, although some orthoepists have traditionally prescribed the pronunciation...

s, which could be released from inside the submarine were provided together with external air connections and a charged high-pressure line which could provide air to any manned compartment or the living spaces. Furthermore the main ballast tanks could be blown from either end of the ship.

Propulsion

Swordfish had two Parsons

Parsons Marine Steam Turbine Company

Parsons Marine Steam Turbine Company was a British engineering company based in Wallsend, North England, on the River Tyne.-History:The company was founded by Charles Algernon Parsons in 1897 with £500,000 of capital, and specialised in building the steam turbine engines that he had invented for...

 geared impulse-reaction steam turbine

Steam turbine

A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Sir Charles Parsons in 1884....

 sets, each driving one of the two propeller shafts. The turbines were powered by a single Yarrow

Yarrow Shipbuilders

Yarrow Limited , often styled as simply Yarrows, was a major shipbuilding firm based in the Scotstoun district of Glasgow on the River Clyde...

-type boiler. They were designed to produce a total of 4000 shp at a working pressure of 250 pound per square inch which used a superheater

Superheater

A superheater is a device used to convert saturated steam or wet steam into dry steam used for power generation or processes. There are three types of superheaters namely: radiant, convection, and separately fired...

 to increase the working temperature by 100 °F (37.8 °C). She was fitted with two electric motor

Electric motor

An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...

s which had a combined output of 1400 bhp. Two battery rooms each had 64 battery cells. It is uncertain if the ship reached her designed speed of 18 knots on the surface, although it seems unlikely given her increased displacement over Laurenti's original design. Maximum speed was 10 knots underwater.

Swordfish could carry 102 long tons (104 t) of fuel oil

Fuel oil

Fuel oil is a fraction obtained from petroleum distillation, either as a distillate or a residue. Broadly speaking, fuel oil is any liquid petroleum product that is burned in a furnace or boiler for the generation of heat or used in an engine for the generation of power, except oils having a flash...

 which her builders estimated gave her an endurance of 3000 nautical miles (5,556 km) at a speed of 8.5 knots on the surface. On her batteries her submerged endurance was 60 nautical miles (111.1 km) at a speed of 6 knots.

Armament

Swordfish had two tubes for 21 inches (53.3 cm) torpedoes

British 21 inch torpedo

There have been several British 21-inch diameter torpedoes used by the Royal Navy since their first development just before the First World War.They were the largest size of torpedo in common use in the RN...

 in her bow. They were stepped vertically and positioned well back from the stem in a notch from the keel

Keel

In boats and ships, keel can refer to either of two parts: a structural element, or a hydrodynamic element. These parts overlap. As the laying down of the keel is the initial step in construction of a ship, in British and American shipbuilding traditions the construction is dated from this event...

 to preserve the fine lines of the bow. Two 18 inches (45.7 cm)

British 18 inch torpedo

There have been a number of 18 inch torpedoes in service with the United Kingdom. These have been used on ships of the Royal Navy and aircraft of both the Fleet Air Arm and Royal Air Force...

 torpedo tubes were positioned on each beam

Beam (nautical)

The beam of a ship is its width at the widest point. Generally speaking, the wider the beam of a ship , the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position...

 amidships. Each torpedo tube was provided with one reload. Two 3 inches (7.6 cm) gunsThe exact type of 3-inch gun is unknown. were fitted on the deck in disappearing mounts

Disappearing gun

A disappearing gun is a type of heavy artillery for which the gun carriage enabled the gun to rotate backwards and down into a pit protected by a wall or a bunker after it was fired...

, one each fore and aft of the conning tower

Conning tower

A conning tower is a raised platform on a ship or submarine, often armored, from which an officer can con the vessel; i.e., give directions to the helmsman. It is usually located as high on the ship as practical, to give the conning team good visibility....

. They were covered by watertight hoods to preserve the streamlining of the submarine.

Construction and service

Swordfish was ordered from Scotts Shipbuilding and Engineering Company

Scotts Shipbuilding and Engineering Company

Scotts Shipbuilding and Engineering Company Limited, often referred to simply as Scotts, was a Scottish shipbuilding company based in Greenock on the River Clyde.- History :...

 on 18 August 1913 although she was not laid down until 28 February 1914. The start of the First World War six months later greatly hindered her completion and she was not launched

Ship naming and launching

The ceremonies involved in naming and launching naval ships are based in traditions thousands of years old.-Methods of launch:There are three principal methods of conveying a new ship from building site to water, only two of which are called "launching." The oldest, most familiar, and most widely...

 until 18 March 1916. HMS Swordfish was commissioned

Ship commissioning

Ship commissioning is the act or ceremony of placing a ship in active service, and may be regarded as a particular application of the general concepts and practices of project commissioning. The term is most commonly applied to the placing of a warship in active duty with its country's military...

 on 28 April 1916, before completion, and renamed HMS S1 that same day. She was not completed until 21 July.

Captained by Commander Geoffrey Layton

Geoffrey Layton

Admiral Sir Geoffrey Layton GBE, KCB, KCMG, DSO , was a British Royal Navy officer.-Early life and career:...

, her post-completion trials lasted for five months as she was used to evaluate steam power for submarine use. Much was learned about the operation of steam submarines, which helped the subsequent design of the steam-powered K-class

British K class submarine

The K class submarines were a class of steam-propelled submarines of the Royal Navy designed in 1913. Intended as large, fast vessels which had the endurance and speed to operate with the battle fleet, they gained notoriety, and the nickname of Kalamity class, for being involved in many accidents....

 fleet submarines. She proved to be very unstable while surfacing, presumably because she could not pump the water out of her controlled free-flooding spaces quickly enough in the upper part of her double hull. These problems, coupled with the fact that she was too slow to work with the fleet as originally envisioned, meant that she was impossible to make into an effective warship and she was laid up after her trials.

In July 1917 S1 reverted to her original name and was converted to a surface patrol vessel between 27 June 1917 and 24 January 1918. Her torpedo tubes and disappearing guns were removed. She was given a forecastle, a bridge and her funnel was fixed in place and extended. She was rearmed with a pair of 12-pounderThe exact model of 12-pounder fitted is unknown. (3 in (7.6 cm)) guns and 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, weapons more suitable for her new role as an anti-submarine patrol boat. Swordfish joined the 1st Destroyer Flotilla at Portsmouth

Portsmouth

Portsmouth is the second largest city in the ceremonial county of Hampshire on the south coast of England. Portsmouth is notable for being the United Kingdom's only island city; it is located mainly on Portsea Island...

 upon completion of her sea trials, but nothing is known of her subsequent service.

Swordfish was paid off on 30 October 1918 and stricken from the Navy List by January 1919. She was sold for scrapping to Pounds, of Portsmouth

Portsmouth

Portsmouth is the second largest city in the ceremonial county of Hampshire on the south coast of England. Portsmouth is notable for being the United Kingdom's only island city; it is located mainly on Portsea Island...

 in July 1922, but was reported to have been resold to Hayes, of Porthcawl

Porthcawl

Porthcawl is a town on the south coast of Wales in the county borough of Bridgend, 25 miles west of the capital city, Cardiff and 19 miles southeast of Swansea...

in 1923.