Is it this simple?

[sstuller]

I traveled back and forth several times a day for five months with my dink using a C30 MinnKota, a 15 watt panel, an old fashioned shunt controller and a 35 AH AGM battery. Admittedly it was only several hundred feet to the boat and back but I never needed shore power to recharge the battery. This is all low tech and it worked fine. Is there any reason why this system can't be scaled up to a larger boat? Thanks.

[delmarrey]

Several hundred feet? Sure!
It's the longevity of the battery, and the recharge rate that'll get ya.

[GordMay]

Greetings and welcome aboard the CF, sstuller.

The relationship between boat length and displacement (hence power required to drive it) is non-linear.

[Horror Hotel]

Do you want to cruise to far off locations? Possibly motor for 72 hours to find safe harbor? Lagoon couldn't get it right with all their effort, not a good sign. I've considered going electric, but the life blood of my system would be a new diesel genset. Have unlimited range is what makes it a useful boat. Batteries and solar limit you to in and out of the harbor. Depends what your doing. I've travelled 3000 miles since oct. If I had waited for wind or solar I wouldn't have pulled it off. Are you a romantic sailor ghosting along or a traveling cruiser who wants to go places and see things.

[a64pilot]

Originally Posted by sstuller

Is there any reason why this system can't be scaled up to a larger boat? Thanks.

Two big things, available area of solar panels ( you'd almost have to tow a barge that was purely set up as a solar collector I think) and money. You'd spend millions replacing tens of thousands of dollars of Diesel fuel. But yes it could be done.
You would be surprised at how many people that thought the panel on the roof of some Prius, ran the air conditioner, where really it's all it can do to run a little computer fan to try to pull some of the hot air out of the car.
Available energy from a solar cell is actually quite small, so you have to be super efficient, and use very little energy and accept long re-charge times.
Your use for example, is your battery staying topped up, or are you slowly depleting it? Your use sounds like you could run for a month on battery only.

[uncledom]

A hybrid system with a very large diesel gen that can keep the boat running at cruise is the optimum scenario. To convert would cost far more up front than to replace an old engine and be on your way. I see Hunter is playing with a system but I don't know if any manufacturer is 100% commited to a "green" sailboat. There are a few third party electric engine manufactureres that can design a whole system for you but ohh the price.

[sstuller]

I bought the panel from Harbor Freight. It was secured to the pontoons of the inflatable with the battery box underneath. I was living aboard on a mooring at the time. It amazed me that I could travel between the dock and the mooring day after day, week after week, month after month with the MinnKota without a problem. It was one of the most reliable equipment systems I've ever had. Thanks.

[SkiprJohn]

Originally Posted by sstuller

I traveled back and forth several times a day for five months with my dink using a C30 MinnKota, a 15 watt panel, an old fashioned shunt controller and a 35 AH AGM battery. Admittedly it was only several hundred feet to the boat and back but I never needed shore power to recharge the battery. This is all low tech and it worked fine. Is there any reason why this system can't be scaled up to a larger boat? Thanks.

Nope, no reason at all. Do a search for electric power here and you'll see long discussions on the subject.

Our club does the same thing for our International Marieholm Folkboat (26 footer). We used a larger MinnKota until we got a Torqeedo.