Although primarily for model planes, there is a flight sim called EasyFly which also works with model boats. You can download several scenes and models, and also has the ability to work with your own transmitter. All you need is a lead from the Tx's trainer socket to the PC. Since most modern PCs are devoid of any serial ports, a cheapy lead can be purchased for about £10.00, which plugs direct from the transmitter and then into a spare USB port.