T-Pain Is On A Boat: Re: [Electric Boats] Parallel DIY

Saturday, September 7, 2019

Re: [Electric Boats] Parallel DIY

Great idea, parallel hybrid using your existing twin diesels and propulsion system is possible. Running the diesels will give you heaps of regen so you will need plenty of battery storage. You would have to check how the regen works on the electric motors if you put the diesel in reverse. It may only need some additional programing of the controllers if required. I assume being a power cat you have two prop shafts and props. You could trial it on one shaft before committing to both. The standard options to transfer the power to the prop shafts from an electric motors are belt or chain. Connecting pulleys or sprockets to the shafts aft of the gear boxes could be done using tapered bushes. Split two piece collars are no advantage as the pulleys or sprockets still have to be slipped over the shaft. You probably have a split collar at the flexible coupling aft of the gearbox. If this is the case then you can disconnect here and slip the shaft back to get the tapered bush and pulley on. Most importantly consider that you are putting transverse loads into the shaft from the electric motor, an additional bearing may be required on the shaft to take the transverse loads away from the flexible coupling and cutless bearing. Apart from the extra load on the shaft and possible abnormal wear on the gearbox components not forgetting possible space/access restrictions, I do not see why its not feasible.

On Sat, Sep 7, 2019 at 4:07 PM rjmcarthur@gmail.com [electricboats] <electricboats@yahoogroups.com> wrote:

We have a power cat with twin diesels. Rather than going electric only, or serial hybrid, we are thinking of at least starting by keeping the diesels and seeing how we go as a parallel hybrid.
The parallel hybrid would have a new electric motor to a speed reduction unit (two differently sized pulleys), then by a belt to a wheel attached to the prop shaft. The attachment would be after the gearbox-engine, as our gearbox can freewheel safely and the diesel would be out of gear.
We may start with one or two Thunderstruck 10kW kits or something similar.
However, I can't work out how to connect the electric motor to the prop shaft. Obviously a wheel (pulley? what do you call it?!) to run the belt on, tightly locked on the prop shaft (ours is 40mm). Preferably using a split collar to reduce maintenance cost (haulouts).
Does anyone know any solutions?