Afternoon All
Made some progress getting the motors / ESCs tested and basic radio configuration, also getting my head around using an SBEC for Rx and general 5V power with a third 4S LiPo for powering everything but the motors. That 4S will be run through the 8A SBEC for 5V and several 12V regulators for other requirements such as amplifiers, pumps, fans. (In the pics below the motors are running on 3S LiPos, eventually they will be on 6S.)

The two motors powered up in the prototype mounts, the foreground mount has cups around the bobbin mounts to prevent too much movement but maintain the isolation of the motors:

They're silky smooth all the way up the rev range, very pleased.
The two FrSky Neuron 80 ESCs connect to the LiPos via XT90 anti spark connectors:

I'm happy with the use of an aluminium case on my 1/10 build to house the ESCs, it combines fans and water cooling certain areas, it'll be same with this build. I had to retrofit the cooling on the 1/10, it'll be built in this time around from the start.
Rx is same as the 1/10 build, the FrSky R8 Pro, this has 8 channels built in plus telemetry and can extend out to 24 channels using the SBUS:

8A at 5v available from this FrSky SBEC:

I'm using a rudder servo for each rudder, not sure if this is overkill but the rudder blades will be substantial and it will allow some tweaking in the programming as they'll be independent, 2 x 25kg metal geared digital servos:

And just because its on my desk at the same time... The sound system under development. The rails and PCB clips are 3D printed, a bit of space under the PCBs to allow wires to be (eventually) routed, and allow ventilation. Once I have the footprint arrived at I'll make a box to mount the system, this will have one or two fans to maintain an airflow. This will be mounted to the side of the LiPos, on the opposite side of the hull will be a similar 'box' with Rx and other electronics, switches and so on. Same arrangement / layout as the 1/10 build. For reference the rails below are 100mm long.

Similar approach to the sound system I made for the 1/10 build... But there's going to be a separate sound system for each 'engine', so 2 x independent V8 sounds, and they'll start / run 5 seconds apart. So you hear engine 1 start and run, then engine 2 start and run. Two Arduino Pro Minis supplying the sounds then two amplifiers that will drive two speakers, and maybe two audio exciters. I've had it running and its working, sounds good to me, a deep rumble... This stage is getting the parts more integrated, then I'll record the sounds and push it up to YouTube.
I want to get these various systems integrated and boxed ready to install into the hull so I can cut the hull frames for installation before going much further with the hull build.
Best regards to all..!
David.