Another project based on Wendels initial small fast attack boat design, was a submergible hydrofoil. Equipped with a Schnorchel and periscope, the small vessel should have been able to set itself on the ground of the sea in shallow waters.
The operational pattern behind this idea was the following:
With a target approaching this position, the hydrofoil should surface by blowing its dive tanks and make a fast attack on the enemy ship. After that it should disengage at top speed.
There are not detailed technical data available, but it is almost certain that this project should have had a similar size, armament and performance than the other Wendel fast attack boat designs.
None of these vessels was ever build.