Yeah, I chose 5hp as as reasonable, pootling down the river at 3-4 knots number. Because that's exactly what my boat does with my 5hp aux engine for maneuovering in the marina.
But 5hp being directly generated from solar? No chance at all.
Solar panels run at about just over 20% peak efficiency. As far as I know there are some nudging towards 25% efficiency, although they don't last at all. But let's say a nice big leapthrough is made to 50% efficiency. So what's currently 400W panel becomes an 800W one for the same size.
5HP = 3.7285KW. For the sake of man maths, let's call it 4KW.
4KW would be 5x panels (Our new super efficient 800W panels).
These panels are about 1.7 metres long, by 1.5 metres wide. So you need to mount 5 of them. On your rib.
And then, a typical day is a long way off peak efficiency, based on panel direction, local weather conditions, time of day and time of year.
So to realistically produce your 5hp on these new 800W panels, you'd want to double up. So 10 of them.
Gonna need a much bigger boat. But that'll need more hp to pootle round.
I think batteries are more viable as a aux power supply. Forget onboard solar on a rib - although, by the same token, have a look at the latest IMOCA vessels - what some of them have done, replacing the diesel with electric and then using deck space and wind turbines to generate power. But their primary mode of operation is sails, anyway, and then they often get towed in and out of harbours and such like by a rib. With a big outboard engine.
In the case of thrustme, do remember the size of the boat the OP has tried it out on. It looks great as a little motor for the tender. But even so, the panels to support the thrust me on a tender would be bigger than the boat.
But panels on the coachroof (and wind turbine on the stern) of your yacht, that your thrustme is plugged in to, to keep it fully charged when not in use - yes, absolutely.
P.S. Whereabouts in Plymouth do you operate? I did my marine engineering degree there - absolutely my favourite city in the country. All the things that a city has/needs, but only a short drive/boat away from some of the most beautiful and breathtaking places in the country. IMVHO. I have been giving some though recently to a Masters or PhD, but practically I'd need to base it a little more locally to me now, than Plymouth.
BLACK PIG
Piglet
