.jpg) HM CMB No 4 inImperial War Museum London (1920) | |
| History | |
|---|---|
 United Kingdom | |
| Name | HM Coastal Motor Boat 4 |
| Ordered | 1916 |
| Builder | John I. Thornycroft & Company |
| Acquired | 1916 |
| Out of service | 1919 |
| Status | Museum ship |
| General characteristics | |
| Type | Coastal Motor Boat |
| Displacement | 5 tons |
| Length | 45 ft (14 m) |
| Beam | 8 ft 6 in (2.59 m) |
| Draft | 2 ft 9 in (0.84 m) |
| Propulsion | 1 shaft Thornycroft V-12 petrol engine which developed 275 bhp (205 kW) |
| Speed | 24.8 kn (45.9 km/h; 28.5 mph) |
| Complement | 3 |
| Armament | 1 ×18-inch torpedo |
HM Coastal Motor Boat 4 is the torpedo boat used when LieutenantAugustus Agar earned a Victoria Cross for carrying out a raid on Soviet warships inKronstadt and sinking thecruiserOleg.
It was one of a large series of small, fast, shallow draughtCoastal Motor Boats used during theFirst World War. She was designed byJohn I. Thornycroft & Company ofHampton,England, ordered in January 1916, built by them and delivered that summer.
CMB 4 was 45 feet (14 m) long and 8 ft 6 in (2.59 m) in the beam. She displaced 5 tons drawing 2 ft 9 in (0.84 m) of water. Power was a 275 bhp (205 kW) Thornycroft V-12 petrol engine driving a single propeller and achieved a top speed of 24.8 knots (45.9 km/h). The boat was armed with one18 inch (450 mm) torpedo and two single .303 in (7.62 mm)Lewis machine guns for the attack onOleg. It was operated by a crew of three.
In May 1916, LieutenantW. N. T. Beckett took command of the newly built HM Coastal Motor Boat 4. In December 1916 he proceeded toDunkirk in charge of the 3rd CMB Division and operated on the Belgian coast. Beckett was in command of a Divisional CMB attack on German destroyers atZeebrugge on 7 April 1917; as a result one was sunk and one very seriously damaged. For these actions Beckett wasmentioned in Despatches and was awarded theDistinguished Service Cross (DSC).[1]
The boat, under the command of LieutenantAugustus Agar, was made famous by his part in theBritish operations in the Baltic Sea against the Bolsheviks in 1919, where she operated with her sister ships in activities such as the raid on Kronstadt.[2]
After the action the boat was returned to the United Kingdom, where it was on display first at theImperial War Museum inLondon and then at theVosper works on Platt's Eyot (island) on theRiver Thames nearKingston for many years with aVictoria Cross painted on the side until the Vosper works there closed. It was then restored and displayed (with details of the action but with the painted VC removed) at the Imperial War Museum's out-stationImperial War Museum Duxford nearCambridge.[3] In July 2019 the boat was moved to Boathouse 4 in thePortsmouth Historic Dockyard, where she is being displayed above a full-size, working replica being constructed by volunteers. The replica boat will be ready for sea trials in the spring of 2022. CMB 4 remains in the ownership of the Imperial War Museum, and is currently on loan to Boathouse 4.
Agar's VC is held by the Imperial War Museum in London.[4]
The boat was inscribed on the National Register of Historic Vessels in May 1996, becoming part of theNational Historic Fleet.[5]