R boat

The R boats (Räumboote in German, literally "clearing boats", meaning minesweepers) were a group of small naval vessels built as minesweepers for the Kriegsmarine (German navy) before and during the Second World War. They were used for several purposes during the war, and were also used post-war by the German Mine Sweeping Administration for clearing naval mines.

Twenty-four boats were transferred back to the post-war German Navy (the Bundesmarine) in 1956 and remained in service until the late 1960s.

In 1954, the Indonesian Navy ordered 10 ships of a modified R-boat design (the Pulau Rau-class) from Abeking & Rasmussen in West Germany.

Design and construction
The R boats were nine classes of motor minesweepers built for the Nazi German Navy (the Kriegsmarine) from 1929 to the end of World War II. They had standard displacements ranging from 60 to 160 tons and were from 37 to 41 meters in length. Originally armed with one to two 20mm guns they were up-gunned during the conflict, typically to carry six 20mm guns. The classes from R-41 onwards carried an additional 37mm cannon. The R301 group were also armed with two torpedo tubes and re-designated escort minesweepers. Two groups of R-boat, the R-17 and the R-130 classes, were equipped with Voith Schneider Propellers for increased manouverability. Some 424 R-boats were built, by specialist shipbuilders Lürssen, of Bremen-Vegesack; Abeking & Rasmussen, of Lemwerder; and Schlichting (de), of Travemünde.

World War II
A total of 424 boats were built for the Kriegsmarine before and during World War II. The German Navy used them in every theatre including the Baltic, Mediterranean, the Arctic and the Black Sea. In addition to its designed use as minesweepers, these boats were used for convoy escort, coastal patrol, minelaying and air-sea rescue.

Post-war
About 140 R boats survived the war and these were distributed amongst the Allies. Some were used by the German Mine Sweeping Administration (GMSA) to clear western Europe of naval mines. Twenty-four boats were transferred back to the post-war German Navy, the Bundesmarine, in 1956 and were used until the late 1960s. An unusual feature of these ships is the use of Voith Schneider Propellers on approximately one quarter of the boats for extra maneuverability.

Foreign R-boats in Kriegsmarine service
Additionally, a number of captured vessels were used by the Kriegsmarine and designated "Foreign R-boats" (R-boote Ausland). These were: The Germans also had a number of vessels constructed at shipyards in occupied territories; four boats of 70t (RA101-105) and six of 80t (RA106-112) at Dutch yards, and four boats of 75t (RA201-204) at Norwegian yards.
 * Six ex-Dutch boats, numbered RA 51 to RA56
 * Two ex-British (RA9, RA10)
 * Eight ex-French (RA1-8)
 * Over sixty ex-Italian (RA251-268 and RD101-149).

A further 8 coastal motor fishing boats were designated as auxiliary R-boats and named R111-R118 in the 11th R-boat flotilla.

R boat units
In the inter-war years and during the Second World War, a total of twenty Räumboots-Flottille (German for "Minesweeper Flotillas") were created. While most were dissolved late in the war or after the German surrender, a few were kept for use by the German Mine Sweeping Administration (GMSA) and dissolved post-war. An additional flotilla was created in the immediate post-war, also for use by the GMSA.

In Bundesmarine service
In 1956 twenty-four vessels were re-fitted and returned to the newly-formed West German Navy, the Bundesmarine. These were the Aldebaran group, nine vessels of the R-41 class, the Capella group, thirteen vessels of the R-130 class, and the UW-6 group, four vessels of late-war construction.

Aldebaran group
The Aldebaran group were nine vessels of the R-41 class. These were 38.7 meters in length, had a standard displacement of 125 tons, and were armed with one or two 20mm anti-aircraft guns.

Capella group
The Capella group were thirteen vessels of the R-130 class. These were 41.1 meters in length, had a standard displacement of 150 tons, and were equipped with 2 x Voight-Schnieder propellers. They were armed with one or two 20mm anti-aircraft guns.

UW-6 group
The UW-6 group were four vessels of the R-218 and R-401 classes. They were 39.7 meters in length, and had a standard displacement of 140 tons.

Online sources

 * R Boat at German Navy.de
 * Räumboots-Flottillen at Lexikon der Wehrmacht.de