Beginning in 1972 four trial boats were built by Peenewerft. After the test  and trial phases 30 hulls were produced by VEB Schiffswerft, Rechlin, and equipped in Wolgast.

The first boat of the series was commissioned in 1974, 29 other boats were built until March 1977. The boats were substituted the restructured LTS-Brigade with three Divisions of 10 boats each. After 1976/77 the boats were operating in the 6. Flotilla in Dranske in two brigades of 15 boats each (7. LTS-Brigade: Boats 911 - 915, 931 - 935, 951 - 955; 9. LTS-Brigade: Boats 921 - 925, 941 - 945, 961 - 965).

Libelle PtNo 952 in the German Naval Museum Wilhelmshaven                                                          Pictures: U. Skrzypski

 Boat 945 sank 1986 after a collision with a Missile-S-Boat of OSA I-class(Projekt 205), one person was killed. Serial No. 131.410 Boat 925) was until summer 2008 in the Scientific Collection of Peter Tamm in Hamburg (today: Internationales Maritimes Museum)  - the boat was transferred to Luftfahrttechnisches Museum, Rechlin, while the Tamm-collection moved from Elbschaussee to Koreastrasse. Serial No. 131.422 (Boat 952) was initially at Schifffahrtsmuseum Rostock, now at  Deutsches Marinemuseum Wilhelmshaven, Serial-Nummer 131.426 (Boat 961) is at Militärhistorisches Museum Dresden,  and Serial-Nummer 131.408 (Boat 924) is in  Marinemuseum Stralsund/Dänholm . All other boats have been broken up. 

Libelle PtNo 925 until summer 2008 in Scientific Collection Peter Tamm, Hamburg - Pictures: K. Scheuch
Libelle PtNo 925 from summer 2008 in Luftfahrttechnisches Museum, Rechlin - Pictures: K. Scheuch
Weapons of the KTS - Torpedoes, Mines, ZU 23 - Fotos: K. Scheuch
Bridge, at its side Minethrower, at the Stern ZU 23 with Weather-Shield- Fotos: K. Scheuch

Meeting of ex KTS- and LTS-Sailors at Rechlin 06.10.2012 - Picture: Uwe Weiß