HI Bluethunder
Yes I thought it might be that high. Electronize do a high capacity controller but its quite pricey. Mtroniks are another supplier and they advertise a 40amp version for about A£50. I am not the best person to advise you as I prefer brushless motors for fast vessels and most of my other models are scale, so no real need for power hungry ESC's! There are several posts on this site relating to motor/ESC set ups so hopefully you will find advice from one of them. You may need to consider water cooling for both motor and ESC. Hopefully another member will pick up the thread and give advice. Good luck. Dave

HI Dave, Thanks for the response, checked the motor...fine
and is suppressed. As a returner to the hobby (after 40 odd years) I have to get to grips with new tech equipment !
Don't have a meter, however Ripmax advise 35amps max.
Tried to contact Electronize today ref capacity of their controller but may be snowed out !
Will try adjusting the controls as suggested, meanwhile some advice on a suitable controller manufacturer (just in case) would be good.
Les

HI Bluethunder
The sparks you can see are the relay contacts sparking. I suggest you disconnect the speed controller and check the motor before you proceed further. if you can also check the amperage drawn with a meter this will enable you to select a suitable ESC. is the motor suppressed? it is possible that it is generating electrical interference that is causing the ESC to switch between forward and reverse. The ESC you have is possibly rated at 15amps so if your motor has been drawing more current you may well have burnt the relay contacts. There are two trim pots on the ESC. They may be dirty and moving them with a thin screwdriver, whilst the transmitter and receiver are switched on, may solve the problem. if you need a new ESC then we need to know the amperage or motor to advise.
Dave