Hi Richard and welcome to SimScale!
That looks like a very interesting project that you can definitely investigate some of the objectives you mentioned using our platform. I would have a look at 6 DOF simulation projects as this one right here: Wake Development of a Boat. For the propulsion system we can use the so called AMI or MRF approach. For the speed we can use a result and investigate the momentum/torque. We have to make sure though that a transformation into the local coordinates takes place to get the actual torque from the propulsion system. You can open a new section in the Project Support section and either one of the PowerUsers or someone from the SimScale staff will jump in to help you out.
Looking forward to see some first results on this!