In process of restoration of H-23. I contimplating using an all electric (130lbs thrust) dual trolling-motor configuration to replace gas outboard engine. Plan to utilize solar panel to recharge and a bank of three 12 volt deep-draw sealed gel-type marine batteries with a voltage isolation circuit for the 12 volt lighting and instrument power. I understand this motor configuration is used to power pontoon boats in pristine-water-regulated areas. My thoughts are the entire investment will cost less than $1200 (8 hp Honda 4-cycle @ $1800?), and will require no gasoline purchases, nor will it polute the environment. Question for the engineers out there: What amount of thrust is required to push an H-23 against 20 knot winds in two foot chop at a rate of three knots? perhaps I should call Hunter on this one? Regards, Dave
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Don Alexander
I may be able to assist
Dave, Last year in England I took part in some comparative tests of the various trolling motors on the market and have just done some ball park calculations as to the thrust required and endurance of the batteries for your application. It looks just possible to achieve 4 knots in still water but you may have to put up your rag and string if it gets choppy. Assuming your use is mainly weekends, and that you will be reliant on solar power for recharging during the other five days, you will need substantial solar panels. (4hrs/day @ 7.5 amps to replace 5 hours of motor running), so this might be a summertime activity only Also the number of useful discharge cycles available from the batteries before they need replacement will result in costs which probably exceed the fuel costs on a petrol outboard. As my mother always pointed out, "The sun only shines on the righteous", so I hope you are not lacking in this essential attribute! Lastly,in the event that you exceeded the range of your batteries you might need to go into a marina for a quick charge. In this case you will also need to carry a high rate mains charger - or have a small outboard just to get you home. If you are really serious please e-mail me with your ID to donalex@compuserve.com. Regards, Don Alexander.
Dave, Last year in England I took part in some comparative tests of the various trolling motors on the market and have just done some ball park calculations as to the thrust required and endurance of the batteries for your application. It looks just possible to achieve 4 knots in still water but you may have to put up your rag and string if it gets choppy. Assuming your use is mainly weekends, and that you will be reliant on solar power for recharging during the other five days, you will need substantial solar panels. (4hrs/day @ 7.5 amps to replace 5 hours of motor running), so this might be a summertime activity only Also the number of useful discharge cycles available from the batteries before they need replacement will result in costs which probably exceed the fuel costs on a petrol outboard. As my mother always pointed out, "The sun only shines on the righteous", so I hope you are not lacking in this essential attribute! Lastly,in the event that you exceeded the range of your batteries you might need to go into a marina for a quick charge. In this case you will also need to carry a high rate mains charger - or have a small outboard just to get you home. If you are really serious please e-mail me with your ID to donalex@compuserve.com. Regards, Don Alexander.
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Paul
Ask The Pro's
Dave, If you want good information on trolling motors then you should ask the experts. That is the Bass Pro's, who have years of background on how much time you can expect from a charge, how many batteries are needed, battery life and ect. I like the way you're thinking as everyone knows a gas engine only fails when you need it most. You should re-think your concern about about heavy air because the motor will be used mostly in dead calm conditions. When we get 20 knots of wind on Indian Lake we want to see you on the race course with the rags up. We have a member ILYC that uses a trolling motor on a Highlander to get in and out of the channel and seems happy with it. Paul
Dave, If you want good information on trolling motors then you should ask the experts. That is the Bass Pro's, who have years of background on how much time you can expect from a charge, how many batteries are needed, battery life and ect. I like the way you're thinking as everyone knows a gas engine only fails when you need it most. You should re-think your concern about about heavy air because the motor will be used mostly in dead calm conditions. When we get 20 knots of wind on Indian Lake we want to see you on the race course with the rags up. We have a member ILYC that uses a trolling motor on a Highlander to get in and out of the channel and seems happy with it. Paul
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Bob Howie
Thrust math
First, you are to be commended on your attempt at "green" propulsion. I think it's a pretty damn good idea for enclosed water. No engineer am I, but a couple of things come to mind; if you are taking that 20 knots and that size of chop on the nose, you are probably going to have to be able to push your boat along at a minimum of 25 knots in order to net out 3 knots. Next, my brother, who fishes pro-am BASS tournaments, tells me that he doesn't know any trolling motor configurations that can accomplish that kind of push for anything resembling an extended period, so I don't think you're gonna have much luck if you are facing a serious headwind and sea. And, the last thing, I don't think just 3 12-volt batteries are going to give you the kind of power you'd require anyway. A golf cart can run 15 miles per hour, but it carries a sizeable number of batteries in order to do that. On the other hand, there are some electric motors that have been adapted to this kind of application and there are some boats known as "harbor launches" that use electric v. petrol powered engines. You might look to see how they solved this issue since their have something of an approximate weight as that of your Hunter. Good luck. If you get the problem solved, consider posting it. I'd like to hear how you made out. Regards, Bob
First, you are to be commended on your attempt at "green" propulsion. I think it's a pretty damn good idea for enclosed water. No engineer am I, but a couple of things come to mind; if you are taking that 20 knots and that size of chop on the nose, you are probably going to have to be able to push your boat along at a minimum of 25 knots in order to net out 3 knots. Next, my brother, who fishes pro-am BASS tournaments, tells me that he doesn't know any trolling motor configurations that can accomplish that kind of push for anything resembling an extended period, so I don't think you're gonna have much luck if you are facing a serious headwind and sea. And, the last thing, I don't think just 3 12-volt batteries are going to give you the kind of power you'd require anyway. A golf cart can run 15 miles per hour, but it carries a sizeable number of batteries in order to do that. On the other hand, there are some electric motors that have been adapted to this kind of application and there are some boats known as "harbor launches" that use electric v. petrol powered engines. You might look to see how they solved this issue since their have something of an approximate weight as that of your Hunter. Good luck. If you get the problem solved, consider posting it. I'd like to hear how you made out. Regards, Bob
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Tim Schaaf
Check Latitude 38
In the last few months there have been a few articles about people who have done just what you are thinking about, but on sailboats of 30 feet or so. They seem to have liked the conversion, BUT, these are all keel boats, and the considerable weight of the batteries has become part of (or replaced) the fixed ballast. It might be that this weight would not do so well on a smaller boat. Then again, if we are just talking about getting in and out of the slip, you would probably do just fine. Anyway, check the Latitude 38 website (www.latitude38.com) for their articles in the last two to four months. Good luck. By the way, a guy came through Cabo two years ago with a Cal 34 that was electrically powered. Strangest set up you ever saw...TWELVE big solar panels on an arch that extended eight feet behind the cockpit, a water propelled generator on the bottom of his keel, and lots and lots of batteries. He was going cruising, hopefully not through cloudy windless areas of the doldrums. I don't know where he wound up, but it was one interesting boat! AND, he DID, in fact, make it to Cabo!
In the last few months there have been a few articles about people who have done just what you are thinking about, but on sailboats of 30 feet or so. They seem to have liked the conversion, BUT, these are all keel boats, and the considerable weight of the batteries has become part of (or replaced) the fixed ballast. It might be that this weight would not do so well on a smaller boat. Then again, if we are just talking about getting in and out of the slip, you would probably do just fine. Anyway, check the Latitude 38 website (www.latitude38.com) for their articles in the last two to four months. Good luck. By the way, a guy came through Cabo two years ago with a Cal 34 that was electrically powered. Strangest set up you ever saw...TWELVE big solar panels on an arch that extended eight feet behind the cockpit, a water propelled generator on the bottom of his keel, and lots and lots of batteries. He was going cruising, hopefully not through cloudy windless areas of the doldrums. I don't know where he wound up, but it was one interesting boat! AND, he DID, in fact, make it to Cabo!
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Rick Webb
Been Wondering
Why there is not a Hybrid Outboard out there. There are very quiet compact generators and very powerful electric outboards. If the two could be combined it would seem ideal for use on small boats. If someone is listening out there I am willing to try it on my boat, just ship one out to me
Why there is not a Hybrid Outboard out there. There are very quiet compact generators and very powerful electric outboards. If the two could be combined it would seem ideal for use on small boats. If someone is listening out there I am willing to try it on my boat, just ship one out to me
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Keith Redfield
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