I had a really nice JAE Mino that Rod Geraghty sold to me. The stub on the Zipp flex shaft assembly broke of on 3 seperate shafts while running the boat. On the third shaft, I did not go out and get the boat right away and water came in through the stuff tube (because the stub and prop were gone). The boat sank to the bottom of the lake. I did not have any foam in it. It was an 1800 mahr 3S battery and a Castle 50 amp ESC. That, along with the motor, etc. was enough to sink it. I Just thought this might help you all in case you are as new to this FE stuff as I am.
Bob