X Craft Submarine From Wikipedia, the free encyclopedia

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1 X Craft Submarine From Wikipedia, the free encyclopedia The X class was a World War II midget submarine class built for the Royal Navy during Known individually as X-Craft, the vessels were designed to be towed to their intended area of operations by a full-size 'mother' submarine - (usually one of the T class or S class) - with a passage crew on board, the operational crew being transferred from the towing submarine to the X-Craft by dinghy when the operational area was reached, the passage crew returning with the dinghy to the towing submarine. Once the attack was over, the X-Craft would rendezvous with the towing submarine and then be towed home. Range was limited primarily by the endurance and determination of their crews, but was thought to be up to 14 days in the craft or 1,500 miles (2,400 km) distance after suitable training. Actual range of the X-Craft itself was 500 nmi (926 km) surfaced and 82 nmi (152 km) at 2 knots submerged. X24 on display at the Royal navy submarine museum Class overview Name: X class Operators: Naval flag of United Kingdom Royal Navy Preceded by: V class Succeeded by: XE class Subclasses: X3, X4, X5-10, X20-25, XT Completed: 20 Lost: 7 (5 scuttled, 1 foundered, 1 collision) Preserved: 1 General characteristics (X class) Type: midget submarine Displacement: 27 tons surfaced, 30 tons submerged Length: ft (15.62 m) Beam: 5.75 ft (1.75 m) Draught: 5.3 ft (1.60 m) Propulsion: Single shaft; 1 x Gardner 4-cyl diesel engine, 42 hp (31.3 1,800 rpm 1 x Keith Blackman electric motor, 30 hp (22.3 1,650 rpm Speed: 6.5 knots surfaced 5.5 knots submerged Range: 500 nmi (926 km) surfaced 82 nmi (151.8 knots (2 mph, 4 km/h) submerged Test depth: 300 ft (91.5 m) Complement: 4 Armament: 2 x 4,400 lb detachable amatol charges Specification The craft were about 51 feet (15.5 m) long, 5.5 feet (1.68 m) in maximum diameter and displaced 27 tons surfaced and 30 tons submerged. Propulsion was by a 4-cylinder Gardner 42 hp diesel engine, converted from a type used in London buses, and a 30 hp electric motor, giving a maximum surface speed of 6.5 knots (12 km/h), and a submerged speed of 5.5 knots (10.1 km/h). The crew initially numbered three commander, pilot and ERA but soon a specialist diver was added, for which an airlock, known as a wet and dry compartment, was provided.

2 The X class submarines' weapons were two side-cargoes - explosive charges held on opposite sides of the hull with two tons of amatol in each. The intention was to drop these on the sea bed underneath the target then escape. The charges were detonated by a time fuse. Service A number of development craft were built before it was felt that a realistic weapon had been produced. The first operational craft was HMS X3 (or HM S/M X.3), launched on the night of March 15, Training with the craft began in September 1942, with HMS X4 arriving in October. In December 1942 and January 1943 six of the "5-10" class began to arrive, identical externally but with a completely reworked interior. These operations were part of a longer series of frogman operations, see human torpedo. Their first deployment was Operation Source in September, 1943, an attempt to neutralise the heavy German warships based in Northern Norway. Six X-Craft were used, but only 2 successfully laid charges (under the German battleship Tirpitz); the rest were lost, scuttled or returned to base. The Tirpitz was badly damaged and out of action until April This was the only multiple X-craft attack. The lost craft were replaced early in 1944 with X20 to X25 and six training-only craft. The Tirpitz On April 15, 1944 HMS X24 attacked the Laksevåg floating dock at Bergen. X22 was intended for the mission, but had been accidentally rammed during training and sunk with all hands. The X24 made the approach and escaped successfully, but the charges were placed under the Bärenfels, a 7,500 ton merchant-vessel along the dock, which was sunk; the dock suffered only minor damage. On September 11, 1944 the operation was repeated by X24, with a new crew; this time the dock was sunk. X-Craft were involved in the preparatory work for Overlord. Operation Postage Able was planned to take surveys of the landing beaches with HMS X20 spending four days off the French coast. Periscope reconnaissance of the shoreline and echo-soundings were performed during daytime. Each night, X20 would approach the beach and 2 divers would swim ashore. Soil samples were collected in condoms. The divers went ashore on two nights to survey the beaches at Vierville-sur-Mer, Moulins St Laurent and Colleville-sur-Mer in what became the American Omaha Beach. On the third night, they were due to go ashore off the Orne Estuary (Sword Beach), but by this stage fatigue (the crew and divers had been living on little more than benzedrine tablets) and the worsening weather caused Hudspeth to shorten the operation,

3 returning to Dolphin on 21 January Hudspeth received a bar to his DSC. X20 and X23 acted as lightships to help the D-Day invasion fleet land on the correct beaches (Operation Gambit), as part of the Combined Operations Pilotage Parties. Operations continued in the Far East with the revised XE class submarines. Lt Ken Hudspeth DSC*

4 Building a 1:15 Scale Model of The X Craft. The large scale of the MBD X Craft makes this an ideal model for pond and lake use. At first glance, the model as supplied looks fairly straightforward, however on closer examination there are a number of points that need debate. If you are looking for a fairly simple build, then I d suggest you use all the parts as supplied and keep the adornments to a minimum. My argument being that these things cannot be seen at twenty feet and underwater. However, that may not appease the purists. Two factors emerge with this model, firstly the masters were made by Darnell, in the 1950 s with very little information and accurate drawings to go on. Secondly, the only plans that seem to be available are those of Paul Kemp in his book, Midget Submarines of the Second World War. It would appear that since his plans were drawn up, the X Craft restoration has become available in the Gosport Museum, and thanks to the Internet, many detailed photographs have become available. Obviously, Darnell s model has the tail end completely wrong. David Merriman suggested cutting off the entire rear end of the model and rebuilding, but this is a lot of work, especially for those of us with limited skills. So, you can either leave it as it is, imperfect, but functional, or make some modifications. Note how the Darnell model has soft curves to the fins, yet the actual boat and Kemp s drawings show these with very straight internal lines. It would not be too difficult for an experienced model maker to fill these curves lines and make them more accurate. The horizontal fins supplied with the kit have a fairly good profile, but are flat, so here we have cut the profile out of a sheet of aluminum. Both sides were built

5 up using modeling clay and shaped it to look more like a chicken leg, having a rounded surface. The leg was place into a plastic coffee can lid after applying release agent, and epoxy poured up to the halfway line. After setting up, the epoxy was drilled with several 1/4 holes to provide location dimples. More release agent was applied to the epoxy and the leg, then Alumilite rubber poured to completely cover with a 1/4 thick layer. Pictured here are the two chicken legs in various stages. The left one is the clay master, and the right one is an epoxy casting that has been sanded down, filled and re-sanded to reduce blemishes etc. These fins will be provided in a future fittings kit for the model. Whether you decide to install the original flat fins or the chicken leg fins will not effect the way you actually install them. Do not try to glue the fins on freehand. You need to completely assemble the entire rudder/plane assembly and install it to line it up correctly. The fins have been placed on a flat surface, the shaft installed and glued into their position using a popsicle stick and hot glue. (This can easily be removed later). A Draw a line (A) from the prop center to the cut line in the hull halves. This is the datum point for the fin and you are going to align centered to this point, then glue it into place using an epoxy paste. Caswell Gas Tank Sealer with Cabosil powder mixed in is ideal. It sets up in approx 45 minutes at 70f, allowing plenty of time for adjustments etc. Sand down the epoxy excess, then fill the joints with Easy Sand filler. You can wipe this along the joint with your finger to get a good smooth profile.

6 X The Deck Details Above left is the detail from Kemp s plans, and above right is an actual photograph of the deck of the restoration in the Gosport Museum. Obviously, Kemp s small hatch, just aft of the oval hatch, is completely incorrect, it simply does not exist. There are three hatches, all the same size as the left-hand one drawn here. A simple way to make these hatches is to take form flashing aluminum and cut it to shape with a pair of scissors. To make the rivets, just press a nail head into the aluminum and the marks will be embossed into the surface. Glue the part onto the deck with CA or epoxy. The Manhole Hatches These hatches are a model-makers dilemma because they are not quite as they first appear. The real hatch lid closes onto a tube which is about 18 tall and leads into the hull. It does not come in contact with the superstructure cladding. In fact, there is a pronounced gap cut into the superstructure which is also cut around the hatch hinges. To make a good representation of this feature one would need to cut a larger circular hole in the superstructure and then further cut around the hatch hinges. The hatch lid would need to be supported somehow underneath the hole. Extra supports of this nature will also add to the above waterline weight, which is not advisable. A simpler method of construction is to ignore the cut-out and glue the hatch lid directly onto the superstructure. With the dark paint job, this lack of detail will never be noticed. See left. The hatches were made by using an upturned beer can, coated with release agent, then filled with epoxy resin. The

7 resultant plug was then mounted into a lathe and a small lip cut around the outside edge. The hinges were made of thin strips of Styrene sheet cut to shape and drilled with a 1/8 drill to accept the cross-bar, which was brass rod. Two slots were cut into the hatch and the styrene strips and brass rod inserted and glued in with CA. The model has two circles scribed into the surface. These are to depict the hatches, but they are incorrect, so ignore them and fill them in with Easy Sand or body filler. The Kemp drawings show the correct position Periscope Guard Rails The Kemp drawings (see right) are somewhat unclear about the detail of the area around the rear of the unit. It looks as if the triangular area is a solid, but on looking at the museum exhibit (see below), it is quite obvious that there is a guard or support rail angled downward. Using some 3/16 diameter copper tube and some 1/8 brass rod, the assembly was soldered onto a strip of brass sheet then CA d into holes drilled into the deck. Pictured right, the unit is installed and ready for painting. The tube is ideally suited for the Snort intake.

8 The Rudder and Rear Planes Once the horizontal fins securely glued on the popsicle stick can be removed and the rudder parts installed. Cut a short length of tube long enough to push the upper and lower rudders apart so they connect with upper and lower vertical fins. Install the rudders using a 1/16 brass rod running through the spacer which is also running through the dive plane. Check that all parts are operating correctly. The plane should have an operating angle of at least 40 degrees. If not, sand or file down the inner edges of the rudders to ensure good movement. The planes and rudder as supplied are a little thick and need to be sanded down about 1/16 on either side to make them look more realistic. Final installation of the rudder and planes is carried out after the propeller and shaft, and rudder push-rods have been installed. The Exhaust Pipe The Kemp drawing and the museum exhibit both show that the exhaust port is much bigger that Darnel s model. Scale off the drawing and cut out the section with a Dremel tool. Make a curved section by using some fiberglass ribbon soaked in epoxy and draping it over a plastic bottle until it sets. Make another piece but this time lay it on a flat plastic surface to cure. Trim the flat piece and glue into a vertical position (see D E in the drawing). Once cured, trim to fit and bond into place the curved piece using more epoxy mixed with Cabosil. Smooth off the inside by dipping a brush in some lacquer thinner and working the material while it is still uncured. Finally, drill a 3/16 hole centrally in the vertical insert and place a small tube to replicate the exhaust pipe.

9 The Bull Ring. A 3/8 piece of brass tube is inset into the bow of the boat. Bond into place with epoxy paste. Any suitably sized brass eye ring with a screw thread can be used for the bull ring or towing connector. Half fill the brass tube with epoxy (Quickwood) and screw in the eye ring. Here is a close-up of the bull ring in the model displayed in the Gosport museum. Pictured right is the bull ring installed into the model Note the aluminum hatches made from roof flashing, The indents were made with a small hex key pressed into the surface while the sheet laid on a soft wooden block. This produces neat hex bumps on the reverse side which look like the nuts on a hatch or door. Glue into place with CA or epoxy.