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Old 26 January 2023, 20:05   #21
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You reckon? I'll eat this keyboard if you get, in our lifetimes, the ability to generate, say 5hp, directly, onboard an average rib.


5HP= 3.75kW
Our 4kW solar domestic solar installation has 20 x200W panels which cover a sizeable barn roof, each panel weighs about 5KG. IIRC in perfect conditions the earth receives around 250W/m2. So assuming 100% efficiency & perfect conditions, you’d need around 4m2/kW of panels, so around 16m2 of panels to generate 5HP, assuming optimal conditions.
As the man said, “we’re gonna need a bigger boat”

https://earthobservatory.nasa.gov/fe.../EnergyBalance
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Old 26 January 2023, 20:30   #22
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Exactly!
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Old 27 January 2023, 08:25   #23
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Which marina are you in?
I am usually in Royal William
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Old 27 January 2023, 08:29   #24
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You reckon? I'll eat this keyboard if you get, in our lifetimes, the ability to generate, say 5hp, directly, onboard an average rib.
My old 150HP probably generated less than 5HP at tickover

So I feel like you are comparing apples with pears, possibly not even fruit

The point *I* was making is that the improvements due soon should mean that a motor like the Thrustme (no apology for staying on topic) will soon be able to run indefinitely in low power modes
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Old 27 January 2023, 09:01   #25
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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.
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Old 27 January 2023, 09:51   #26
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P.S. Whereabouts in Plymouth do you operate? I did my marine engineering degree there - absolutely my favourite city in the country.
Royal William, in Stonehouse

It is a fantastic boating environment, plenty of sheltered rivers and coastline but with so many great places a days cruising away
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Old 27 January 2023, 11:23   #27
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I remember the area well & miss it dearly.
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Old 27 January 2023, 18:47   #28
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I am usually in Royal William
Nice, can't imagine it's cheap there! We're in Millbay marina village but we get fuel from Mayflower, so we're always going past RWY. I saw that massive new Princess in there before Christmas when they had just unveiled it, and then saw Aquaholic's video of it the following day 😂
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Old 28 January 2023, 15:03   #29
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It was much cheaper a few years ago! Nothing seems to be going down these days

Those Princesses are a bit special eh
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