Two pairs of boats were sent to France at different times in mid-1942 and were part of the escort during an unsuccessful attempt to pass a different commerce raider back through the Channel in October.

Two others were transferred back to France where they laid minefields and were unsuccessful in escorting an Italian blockade runner through the Bay of Biscay into the Atlantic.

By the end of the year, all of the Type 37s were either refitting or serving as training ships for either the Torpedo School or U-boat flotillas.

One boat apiece was sunk in 1944 and 1945 and another was so badly damaged that it was written off as a constructive total loss and later scrapped.

The maintenance problems with the boilers were exacerbated by the lack of access to the machinery allowed by the restricted spaces of the lightly-built and narrow hull.

The naval historian Michael J. Whitley deemed "the whole concept, with the benefit of hindsight, must be considered a gross waste of men and materials, for these torpedo boats were rarely employed in their designed role.

[3] As built, the Type 37 class mounted a single 45-caliber 10.5 cm (4.1 in) SK C/32[Note 1] gun on the stern.

[2] The boats were also equipped with six above-water 533 mm (21 in) torpedo tubes in two triple rotating mounts amidships and could also carry 30 mines (or 60 if the weather was good).

Reinforced by the two newcomers, the flotilla helped to escort German blockade runners sailing from ports in the Bay of Biscay en route to Japan in September–October.

They were intercepted by a British force of five escort destroyers and eight motor torpedo boats that sank the raider on 14 October.

T15 was assigned to the Torpedo School in August 1942 and spent the rest of the year and almost all of 1943 either undergoing a refit or serving as a training ship.

T18 remained in France until July after having escorted the Italian blockade runner Himalaya in her failed attempt to break out through the Bay of Biscay to the Far East in late March and having laid a series of minefields in the Channel in May.

During 10–12 and 13–15 October, T13, T16, T20 and T21, screened the heavy cruisers Lützow and Prinz Eugen as they bombarded advancing Soviet troops near Memel.

T13, T19 and T21 escorted Lützow as she bombarded Soviet positions at Memel and Sworbe, on the Estonian island of Saaremaa, on 23–24 October.

Screened by T13, T16, T19 and T21), Prinz Eugen and the heavy cruiser Admiral Scheer shelled Soviet positions during the evacuation of Sworbe, between 20 and 24 November.

On 5 May T17 and T19 helped to ferry 45,000 refugees from East Prussia to Copenhagen, Denmark, and returned to transport 20,000 more to Glücksburg, Germany, on the 9th.