Is this a SEA QUEEN ?
This is very similar to the Tarpon that was produced, by Model Maker plans service, about the same time as the original Aerokits range. Seaspray has shown a pic of the Sea Queen and I am attaching a pic of the Tarpon.
The Taycol Supermarine was a powerful engine but generates a great deal of radio interference especially for 27Mhz and 40Mhz sets. They can be reversed and there is a dedicated site to the Taycol range, just Google and discover how to make the motor reverse with a modern ESC. As they use an electromagnet for the field coils just reversing the polarity doesn't work.
Dave
Dave