This Kort nozzle designed for DT700/750 motors. We use them in 2 our ROVs. They are about 15kg weight because of 12v leed batteries onboard so we limited current to 5A maximum to have long run time. It gives enough speed and thrust to help our divers even if they ask to bring a spare scuba tank. We also use them for small trolling boats, two motors at 10A each one give 5-6 km/h.
We never use them at 20A cause big current means very short battery run time.
If you will use them at high power you should prepare DT700 for it. Our test show this two small screws can not keep the motor from turning at maximum load. Even if you screw them hard they cannot make a good hole. This can lead to a break in the wires and damage to the motor.
I recommend you to drill a sink:
Ring with 3 nuts can be set only this way:
Insert 3 wire through the hole:
Then insert motor shaft in to holder. Make sure that all three wires are laid exactly opposite the hole:
Insert the motor as far as it will go into the holder:
Insert your hex key from DT700 kit in to hole and fix 2 set screws:
Now gently screw the cone nozzle onto the shaft. Tighten it to the stop with a little effort:
The nozzle does not give much traction, but protects the motor wires from damage.
Screw the propeller on the shaft until it stops but do not over tighten then fix it with nut:
DT700 can work underwater as it is but after a few hours wire will corrode even through protective lacquer. You should epoxy it: