USING ELECTRIC PROPULSION WITH SAILBOATS

By Harry Gordon

(1) Mac Davis: I think you are correct in postulating that MinnKota and MotorGuide don't have any idea as to the potential for electric auxiliaries on small sailboats. But I also think that many sailors are oversold on the perceived safety factor provided by outboard power. When Kelpie was outboard powered, its reliability was no greater than, and seem to be in sync with, the presence of wind. No wind, OB won't start and vice versa. Until someone has in fact experienced the joy of gliding slowly and silently along a shoreline and observing the natural world unspooked by the growl of even the quietest outboard, they have no idea of the real advantage of electric power.

Kelpie's current configuration features a MotorGuide 52 5-speed 12 V with 3 blade prop, drvien by 2 size 27 deep cycle batteries hooked in parallel. From the battery location in the recess under the forward end of the cockpit, I ran 6 gauge wires through a 50 amp auto fuse to a MotorGuide quick disconnect female plug mounted in the hole where the lifting keel crank used to be. The motor itself mounts on the same adjustable mount that the outboard would, on the port side some 12 inches outboard from the centerline. .

I don't look on this as a final installation. I'd like to incorporate a switch at the batteries, so as not to leave the plug hot. I'd also like to find a way to mount the motor on centerline so that it could never interfere with the beaching rudder. I would have preferred to put the batteries farther forward, under the V berth, but the additional wire run and difficulty of removing / servicing the batteries in that location put me off. I also have all the parts for an integrated AC / DC system using a shore plug, AC circuit breakers, AC GFI receptacle, expanded range DC voltmeter and two bank battery charger which will allow me to enjoy the services of a marina occasionally as well as keep the system fully charged. I also have another size 27 battery wired to a DC switch panel to service the cabin and navigation lights, instruments and such.

Performance has been adequate to my needs, but will not of course overcome the fearsome 7 knot ebb with 20 knot winds. With a tide cycle of about 6 hours ebb to flood, I am better served by carrying more beer and snacks and just waiting, which suits my philosophy of sailing better. I have yet to draw down even 1 battery on the approximately ¸ mile trip from my canal to the other side of the bridge.

(2) Randy Watkins: I use a 34 lb thrust electric on my 10 ft sail/rowing dingy. It's o.k. but my battery ( a smallish gel 36 Ah ) is good for about an hour. I also have a Montgomery 15 which I may try to use an electric. I'd need to add a 2nd battery and solar charger to make it feasible. The 34 lb is o.k. on mild wind days but it wouldn't be adequate above 10-12 mph wind heading windward.

(3) Jan Lindstrom: We use the MinnKota 36 lb thrust "65t" on our P15. It has 5 forward speed settings, 3 reverse. We have two small gel cells of 31 amp-hr each for a total of 62 amp-hrs nominal, securely fastened down in battery boxes in front of the mast support. In front of that, we have an isolator and on the bottom of the aft-facing cabin wall, immediately aft of the anchor rode bin in the peak, a recharger is mounted. There is a fuse in the system. The recharger is wired to a marine-type elec. inlet on the starboard side of the cabin wall, near the cockpit. The outside plug from shore power can be reached from the cockpit. (We always turn the power off first, tho, at the power "tower" on the pier.)

Wires from the batteries pass under the cockpit to a socket for the motor, located on the inside of the cockpit wall on the port side. It is far enough aft that it's not in the way of someone sitting in the cockpit. We replaced the alligator clips on the MinnKota with a plug for that socket. This was all done 4 years ago by a boat shop and at the time seemed quite expensive, but it's an extremely convenient system. We use the motor for getting in & out of the marina, and when the wind dies or gets too strong for comfort. We don't sail very far from the marina so it works OK for us. The weight forward is very helpful with our trim, as is the lack of a heavy outboard in the back. Since we don't camp overnight in the Potter, the batteries aren't in the way. Limited battery hours are the main shortfall of this system, but also if we did it again, we'd get a slightly more powerful motor for getting back home against the wind. And maybe a total of 3 of the gel-cell batts, the size of which is limited by what I can comfortably lift with one hand.

(4) Dick Boyum: I currently use a borrowed 36 lb. Minn Kota on our P14 "Otter". At every opportunity, I leave it behind. I love sailing with nothing hanging off her transom. When I do use it, I am pleased when it suits my needs. But when it doesn't work out, I hate it. Like a few weeks ago when I used up the battery getting out of the Back Bay (Newport Dunes)against a mild breeze into Newport Bay for and afternoon sail. On our return to the ramp, I dropped sailabout 200 yards from the ramp to use the motor to manuever through heavy traffic (I should have sailed with right-of-way). We got blown into the mud flats. The Harbor Patrol had to pull us out. The other thing I don't like about it is fixable. Because the motor and battery are borrowed, I've done nothing about permenantly installing the battery. It just flops around in the cockpit. As soon as I can afford it, I'm going to purchase a new Honda 2 h.p.

(5) Dan Rickert: I use a Minkota 40# on my Victory 21, a 21 ft, fixed keel, 1400 lb sloop. With one group 27 deep cycle I have returned from 3 miles out and still had plenty of reserve. I only sail on a mountain lake so there are no currents to speak of and I would not try to take this setup out in the ocean.

(6) Doctor Scott: I have a P-15, my second. I have used trolling motors on them for over 6 years now. The one I presently have is a no-name, garage sale special. Small but is great for docking, gunkholing, and nature watching. I power it with a standard auto battery. It will run at full power for nearly 2 hours, longer in short bursts. I have a Honda 2 hp as well, but it is only good for long runs or when I am too lazy to rig the sails.

(7) Mike Canova: I've been using a 24 lb thrust Minnkota on my 1990 15' Potter, and I love it. There were several reservoirs in MD where I used to live that did not allow gas motors, so I got it primarily for there. But I find that I use it all of the time, instead of one of my three small gas motors. I really only want a motor to get away from a ramp when the wind is blowing the wrong way, or to get me home if becalmed. And I like the fact that if a tack takes me too close to the rocks, I can turn the electric on in an instant and get additional assistance. It would be great if there were a prop better suited to our purposes.

(8) Chris Sayer: Akala's setup is identical to Dave's in Tilly Lucy. I run a 31 Ah West Marine gelcell that sits in the cockpit. The manual says I should get an hour at #5 setting, but in reality it seems to get a bit weak after half an hour or so. I usually use #5 to gain steerage way, then throttle back to 3 or 4 to conserve battery life. Once sails are raised, I often unhook the battery and stow it in the cabin to get it out of the way, and achieve better performance. Dave has loaned me his battery to carry in the cabin on a couple of occasions when he has decided to go with the gas motor.

(9) Dave Kautz: ideal for maneuvering around docks and moored boats, better than gas outboard in that regard thanks to instant on/off and three speeds in reverse. Good for short distance travel at speeds of 3 knots or less. Progress is slow into headwinds. I love the smooth, nearly silent running; however, it lacks the strength and stamina of the comparatively rude 2-stroke outboard I also use.

(10) Robert Skinner: While I have a 12 V 28 A electric outboard, a 3 hp 2-cycle gas outboard, and an old Johnson 5 hp Sea Horse outboard, I prefer to use the electric where possible (current below 2 knots, wind less than 20 knots). The 3 hp is said to be adequate for Long Island Sound's 5-knot currents. The 5 hp is adequate for inlets and other hairy situations.

I also use a Honda 1000 Watt 4-stroke generator (~$800, 28 lbs) and a Sears trickle/2/10/20 A 12/24 V charger (< $90) mentioned in posts a couple of months ago. It has settings for gel cells with auto cutoff to prevent overcharging.

Combined with the 28 A trolling motor (used, ~ $100), and a 105 A gel cell battery (~$130) this rig has had adequate thrust for the Chesapeake Bay and lakes and will run continuously for days on end, pushing a P15 at 2-3 knots. The key is the large battery with #6 or bigger wire aft to an outlet for the motor. The big battery provides 4-hour endurance at full throttle with a 28 A motor. I wondered whether there was a cheap improvement to be had from a slightly larger motor, so I tried a 44 A motor, but it provided only marginally better performance. I prefer the electric not only because it has an ecologically smaller footprint, but also because it is light, quiet, and doesn't stink up the car or boat. On top of that, it is the cheapest of the three, even considering the cost of a 100 A gel cell and a maintenance charger. I generally use it just for docking, etc. This rig does require patience and cannot handle strong currents and winds. I plan (or wait) for the tides, and use the wind. But being able to drop the sails and motor silently on battery alone for 4 hours through swamps and along lake shores has let me enjoy the company of animals that would have been long gone if I were using a gas engine. And it is so peaceful. I can heartily recommend the electric approach for lake and bay sailing. The generator is a hefty piece of change, but also serves as emergency power for the house - enough to keep the furnace going in the winter. However, the expense, weight, and complexity of the 1000 W generator and 20 A charger can be omitted for day sailing if the boat is kept near a source of 125 V power for overnight charging. The battery and generator live in the cabin, battery forward secured alongside the compression post, and the generator on the other side slightly aft by the CB trunk, with a flexible exhaust tube to carry hot air and fumes out of the cabin. If the motor is off, the charger can restore a drained battery in 5 hours. The next significant step up would be something on the order of Harry's 70 lb thrust rig, but I share his concerns about its having enough power for really tough situations. They remain the domain of the stinkers. Of course, the battery is also useful for lights, VHF radio, cell phone, GPS, etc. -- and some lakes will not allow gas engines at all.

(11) John McNeely: I own two MinnKota 24-volt 70 lb thrust electric motors thinking that with two motors I'd go twice as fast. I didn't notice any increase in speed at all. The propellers on electrics are generally not designed to push a boat at fast speeds through the water or the kinds of propeller speeds that gasoline outboards are designed for. Although with two motors I may have had somewhere approaching twice the strength, I did not have twice the speed. And since I was using both motors off of the same two batteries I consumed battery twice as fast (I used two deep-cycle wet cell 12-volt marine batteries connected in series to produce the 24 volts needed. They are very heavy). I've kept these two motors for a couple of rubber rafts that I have that my son and I tool around in to fish. I don't use them for the Potter. Instead I went online and bought a 50 lb thrust 12-volt MinnKota from Walmart. Locally I bought a deep-cycle marine gel-cell battery that does not use a liquid in it. I wasn't fond of the idea of battery acid leaking out all over the inside of the boat and into a freshwater lake if I were to get knocked down in the boat. The battery was about $100 and I only have to use one. The motor delivered was $228.21. I have a Nissan outboard but haven't used it yet.

Below is the wiring diagram of the 24 voilt set-up of Harry Gordon's P-14.