How did real life PT boats run their power? All three motors running permanently? Wing motors or just the center motor for cruising and the other(s) for the extra speed when needed?
The "boost" motor(s) could be forwards only brushless on their own channel. From the ones that I have seen so far, brushless give tremendous power to weight, and therefore speed, but primitive reversing and poor low speed control, so are great for flat out running, whereas brushed motors give good control for avoiding slamming into concrete walls when docking.