The start of World War II in September 1939 caused the cancellation of most of the planned Type 39 torpedo boats and only 15 ships were ordered.

It decided upon a slightly enlarged version of the Type 39 with more powerful propulsion machinery to give the ships a speed of 34 knots (63 km/h; 39 mph) and space for an additional twin-gun 3.7-centimeter (1.5 in) anti-aircraft mount.

[4] The main armament of the Type 41 class consisted four 42-caliber 10.5 cm (4.1 in) SK C/32[Note 1] guns in single mounts; one forward of the superstructure, one between the funnels, and two aft, one superfiring over the other.

They also would have received fully automatic 3.7 cm Flak M42 guns in lieu of the semi-automatic SK C/30 weapons of the earlier ships.

The Kriegsmarine originally estimated that T37 would be completed by the beginning of 1945, but labor shortages and other problems delayed the ships by two to three months.

All work ceased at the shipyard on 22 January due to power failures, a lack of workers and the advancing Soviet forces which were approaching East Prussia.

T37 was intended to be finished at the Deschimag yard in Bremen, but was found in Bremerhaven by American troops at the end of the war with no further work having been done.

T40 was towed west on 9 March, bound for Eckernförde with a cargo of a dozen Linsen explosive motorboats aboard, but ran aground at Brösen, Danzig, on the 12th.