Hey Nigel.....I am assuming you were being serious so I will answer your question as such. Although your rotary engine probably revs to 7000 grand all day long, it won't work in a jet. Heres an example. I have a blown big block in my boat and it will hit my rev limiter of 7500 rpm and higher if I let it but this is on the trailer. Once you put it in the water and put a load on the pump everything changes. Now, considering my engine puts out A TON more torque than your rotary engine, I am turning it around 6200 rpm. Where did the other 1300 rpm go? The pump just won't let the motor spin that hard. We can go into this for days on theory of operation but I will make it short. JETBOATS LOVE BIG TORQUE ENGINES. They NEED torque to turn a loaded impeller. Think of your pump as a water brake on a dyno. Thats exactly what its doing. The pump is loaded all the time with water and torque is needed to turn it against the resistance water places on it. Your rotary engine just doesn't produce the TORQUE or horsepower. PERIOD. Hope it helps.