golf cart motor for 34' tartan

[whatknot]

Originally Posted by KTP

Some of these posts who "analyze" the motor and boat then claim 1 to 1.5 knots in calm conditions on a 11,000 pound boat being pushed by a 7hp motor are quite hilarious.

Those of us who actually *have* a electric sailboat are a bit better qualified to comment. On our 34 foot Pacific Seacraft, which is around 13,500 pounds displacement, our electric motor pushes our boat at 1.5 knots in calm conditions using less than 10 amps on a 48V system. That is under 1HP.

On a windy day with some chop we were using 60 amps at 48v to go about 3 knots. That is still only about 4HP.

I will agree that getting to near hull speed uses a hell of a lot of power. At 130 amps we were doing about 5.5 knots in moderate winds. Our current bank is only 250AH so I haven't done extensive testing at that draw. Still kind of waiting on those Trojan Trilliums.

Can you tell me what motor you have?

[u4ea32]

My boat is an Olson 40.

The diesel engine experience was simply awful: noise, vibration, smell, stalling when really needed, expensive to repair, lots of maintenance, lots of spare parts and tools and filters and belts etc required, a big hole in the bottom of the boat for water and weeds, an ecological disaster on every fuel dock visit, trouble with algae and water in the fuel, fuel getting old before it could be burned, ... ETC.

I removed the diesel, tank, etc etc. The vast majority of parts in the boat were directly related to that damn infernal combustion evil. The vast majority of spare parts, spare fluids too. Nearly 800 pounds of crap came out related to that supposedly 350 lb, supposedly 25hp Yanmar 3gm30F.

I actually removed every fuel: the propane went too, and no more dinghy gas either. No dead dinosaurs. No stench of dead dinosaurs. Why does anyone put up with that awful smell?

I installed a 5KWH LiFePO4 battery bank: 4x12Vx100AH, but the actual voltage is about 54V, so a bit over 5KWH. Battle Born GC2 batteries.

I installed a 10KW ElectricYacht air cooled motor, which came with excellent motor mounts, reduction drive, coupling, single handle remote, digital display, all the fasteners, perfect directions. The entire motor weighs less than 50 pounds. I could and did adjust the motor mount bolts with my fingers to align the motor. Nothing about the installations was difficult, and when something went wrong (like I adjusted the motor so it turned the wrong way) Mike Gunning immediately answered his cell phone and in seconds told me what to do to fix my problem.

The total cost of the system including installation was 80% the cost of a new Beta sitting on a crate at the Beta factory.

The total weight of the system, including all wiring, brackets, fasteners, tools, ... everything ... was much less than the 30 gallons of diesel in the tank. About 135 lbs total.

So the new installation saves well over 600 pounds. Hard to find any other way to save that much weight.

The motor is so silent and smooth that the noise now is from the propellor. Ever heard your propellor before? Me neither.

When going down the fairway in the marina, its about 330 watts. Going at marina no wake speed of a bit over 4 knots takes 2KW. 6.1 knots takes 4.8KW. 6.1 knots is the same speed, using the same prop and shaft, achieved by the Yanmar 3gm30f when running flat out.

But the real wonderful thing is that the boat is fundamentally easier to maneuver in the marina with electric power than diesel. The difference is huge, its almost magic.

People ask about range. Well, using math, its 6 nm flat out, 10nm at 4 knots, 15nm at 2-3 knots.

However, the truth is: its a sailboat, so the range is still infinite. Even under pure electric, the range exceeds my needs by over an order of magnitude. And the improvement in maneuvering is huge, otherworldly.

Getting rid of the spares and liquids and tools required for the engine gave me several storage lockers.

Getting rid of an enormous number of problems is difficult to enumerate. The boat is now 100% electric, so the troubleshooting approaches, tools, and spares required is now minimized: you can't get rid of electricity, but you can get rid of dead dinosaurs and the myriad problems related to lots of explosions, explosives, corrosives, corroding parts, wearing parts, ... and did I mention the stench of even a perfect, non-leaking diesel motor?

No smells. Oddly unusual, but remarkably better.

[pete c]

A little late to the party here, but, getting to the OP's questions...

Is it enough to get you in out of the marina in good weather?

Probably. As someone said, a trolling motor would do it.

I haven't read all of this thread, but there was a lot of chiming in about all the other horrendous costs that will make it impractical. These folks seem to ignore the fact that he was getting the entire cart. This means, batteries, I suspect 6x6v, a throttle a means of reversing direction and an on off switch. The only thing he'd likely need to add would be mounting and probably a few pulleys/belt as you'd likely need some gear reduction.

Assuming lots of offshore operation was not in his future, he might find this setup so nice, that he might just rebuild that diesel and sell it. He could then upgrade his battery bank and maybe the motor itself.

I am a big fan of e conversions. I think they are the way of the future and before long will be the aux power choice of most boaters. There are simply too many advantages. Throw in a good PV array and you'll never have to buy one drop of fuel going forward, assuming your power needs are low and sunshine is plentiful. You could bop around the Caribbean for years. Those of you in Norway should probably stick with your oil burner.

[Mauruuru]

I wouldn't use a golf cart motor. 1 Year ago I ditched the diesel ( a Yanmar 3ym30) for a 3 phase PMAC motor and controller and 48 VDC, 220 AH Oasis carbon AGM battery. Sold the diesel for more than the cost of the motor, controller and misc things like meters and reversing switch (I Did use a heavy duty golf cart reversing switch but really didn't need to it was cheap and convenient). The PMAC motor is closed loop water/glycol cooled as is the controller. The motor is rated 30kW and the system is available ready to go out of the box. I also use a 3:1 gear reducer because the motor is capable of 6000 RPM way too fast for the prop. No need to reinvent the wheel folks its available as a marine package online.

I was able to use my existing forward/reverse and throttle at the helm......while I was at it I removed the propane added an induction stove top and converted the entire boat to electic power. The separate house batteries as well as the drive batteries can be charged by shore power, generator, solar, or really any method you choose. I chose Picco 4kW high frequency AC genverter and next phase is solar. Everything except 120 V AC electronics is mounted in the original space of the Yanmar.

Now I sail, motor, or motor sail quietly......and my range is triple the original diesel range when motoring (because of the high efficiency of both the Genverter and the PMAC motor).

Took my time and did it all myself.