golf cart motor for 34' tartan

[valhalla360]

Originally Posted by Adelie

Stock 36v motors are around 8hp but I easily found 36v golf cart motors in the 10.5-12.0hp range.
https://www.golfcarcatalog.com/produ...47%7D2%29.html
https://www.everythingcarts.com/p-46...-dcs-cars.aspx

Actually 36v standard are around 3-4hp. You can get "performance" motors that go higher but this sounds like he is taking an old junk cart and scavenging the motor, so likely has a base model. Your links are for "performance" motors.

Yes, it will work on calm days to get in and out of the marina but as others have said, it's not a simple plug and play solution.

[GILow]

Originally Posted by Sailing August

Hi,
A 36 volt electric motor produces about 8 horse power at 100% load....

Regardless of quibbles about the exact HP the motor produces, I think this is one of the most extraordinarily well thought out posts.

And this was Sailing August's FIRST post.

Thank you Sailing August, I hope you get the formal greeting soon from the mods, but I for one reckon that was an excellent start.

Matt

[GILow]

Originally Posted by Adelie

Where did you get the 8hp number?

Originally Posted by Adelie

Stock 36v motors are around 8hp but I easily found 36v golf cart motors in the 10.5-12.0hp range.
https://www.golfcarcatalog.com/produ...47%7D2%29.html
https://www.everythingcarts.com/p-46...-dcs-cars.aspx

Seriously?! I mean that was a brilliant post, and as you showed yourself, using 8 HP as a starting point was a perfectly valid assumption.

I think telling the poster that you "easily found" other motors is a bit off and totally missed the value in all of the thought and calculation that went into what was their first post.

Sometimes I think CF really is not a very welcoming place. Really disappointed by this response.

Matt

[valhalla360]

Originally Posted by GILow

Seriously?! I mean that was a brilliant post, and as you showed yourself, using 8 HP as a starting point was a perfectly valid assumption.

I think telling the poster that you "easily found" other motors is a bit off and totally missed the value in all of the thought and calculation that went into what was their first post.

Sometimes I think CF really is not a very welcoming place. Really disappointed by this response.

Matt

I think it was a good post and more discussion is good (he is very much welcome)...

But that includes being able to discuss the technical details...and 4hp vs 8hp is a pretty big difference.

On a related note: Used to be able to put the 5hp dingy outboard on a bracket on our 32' 10k lb catamaran...that would top out a little under 3kt in calm conditions. Against a decent headwind...I would agree that we would have been lucky to no go backward.

[Afrakes]

If the motor on the Tartan is original it's probably an A4 and not a diesel. The A4 is a simple motor and easy to rebuild. Big question, what is your $ budget.

[fred4936]

We have what is essentially a 5kw system in our Tartan 27-2. I really like it for what we do with it, which is mostly just to get in and out of our creek. In 7 years it has been very reliable, economical, quiet, and smooth. And lets us sail year 'round when we choose to. I can see it working in a Tartan 34, but only in the calm conditions you stated. We were coming out of another marina into a 30 kt. headwind one day; we got out fine but it was very slow going. Ours is a 48v system, using golf cart batteries. The cost of our system was about half of a new diesel, which was a factor in our decision to convert. In any kind of a headwind or chop I can see potential issues with a smaller system than we have on a larger boat. It may work fine in a calm, but may be disappointing in anything more than that.

[KP44]

It's an expensive conversion. Unless you decide to go electric and retrofit a larger motor. A 30 hp motor with new gearbox, coupler, and re-sized prop; will likely be smooth and quiet. You can replace the lost engine and fuel weight with batteries.
If you do a lot of sailing from marinas with shorepower, it makes sense. Or if you sail most of the time and only motor in anchorages and marinas, it could work out well.

[whatknot]

Thanks for the responses everyone. I got the Diesel engine out this weekend and it is in rough shape. It was sitting in water for a while. I am more interested now than before in going the electric route. I looked at golf cart motors and looks like they would be difficult to adapt a pully/gear to it. So I may decide to buy a forklift motor. I’m hoping to have the Diesel engine apart tomorrow at lunch to determine if it is salvageable.

[akprb]

Are you ever considering long distance cruising or will
it always be daysailing in and out of the marina?

If cruising to far away lands the skills you learn rebuilding the diesel will be of great value. The ones you learn installing the electric, not so much.

[The Sun King]

An electric conversion could be a great idea, but not with a golf car motor. I can't say for the 36v model, but most 48v motors are rated at 3hp for continuous service, with peaks around 30hp with a big controller. Use a drop-in conversion available from several sources. The Elco is probably the best, but is serious bucks.


My boat has been pushed for thousands of miles by a modified Minn Kota 80 lb. troller, the sole power sourrce. The smaller motors are crap, bu the 80 lb and up are solid. I carry a spare and repair kits, but have never used them. Kipawa props will give a little better speed as stock props are speed limited. The maneuverability with vectored thrust is so good you'll never want to go back to a rudder. For a boat your size, there are various electric outboards available.


I assume you don't want to cruise, just get in and out of port with the electric, but cruising is doable. With the right balance of battery and solar I have run up to 19 hours in a day of crossing the Gulf of Mexico, leaving enough in the batteries to run the microwave and coffee pot for supper and breakfast. That's with 350ah of battery on 24v and 1620 watts of solar. Those pesky sails would tend to limit solar power on your vessel, though.



Ir you are going to rebuild the diesel, don't bother with electric, except a trolling motor to get you into the slip during the overhaul. Use the golf car motor as a spare anchor.

[guyrj33]

Originally Posted by GILow

Seriously?! I mean that was a brilliant post, and as you showed yourself, using 8 HP as a starting point was a perfectly valid assumption.

I think telling the poster that you "easily found" other motors is a bit off and totally missed the value in all of the thought and calculation that went into what was their first post.

Sometimes I think CF really is not a very welcoming place. Really disappointed by this response.

Matt

brilliant or not I have to take exception to this part of the post being discussed.
"Based on very limited information. Your electric motor without the gear box, producing 6.8 hp @ approx 500 to 700 rpm will push your boat at maybe 1.0 to 1.6 knots going forward. Add any wind or current to the situation and you are sitting still."

As an experiment I hip tied our inflatable with 2hp motor to our Pearson 10M (13,000lbs, 28' wl) and was able to make 3 knots.
I think there is a flaw with the calculations.

[whatknot]

Thanks everyone. I found a pitted cylinder in the diesel engine so going to see if it can be sleeved. The golfcart motor I was looking at doesn’t have shaft coming out the front so I decided not to use it. I am interested in the trolling motor option. Going to look tonight to see how I can temporarily mount one.

[a64pilot]

It can be sleeved, but if it can be bored within limits, I’d go that route myself.

[Mauruuru]

for all of the anti-electrics you'll always find a reason not to convert. However, there are a number of reasons why the US Navy and others have gone to electric hybrid propulsion not the least of which is efficiency and high torque capabilities of electric drives. Using a diesel powered generator running at its most efficient rpm to generate electricity, coupled with variable speed drive and 3 phase electric motor gives the helmsman 100% torque (theoretically) at every speed from 1 rpm to max and that matters. In a sailboat/displacement hull environment motor HP will be 1/2 to 2/3 of the equivalent diesel to get to hull speed so if you have a 30 HP diesel it should only take 15 HP motor. Other advantages under sail with good wind-regenerative operation makes the motor a generator replenishing batteries. Under light wind conditions a little bit of motor can add 1 to 2 knots of boat speed with little adverse impact on soc.
Costly yes but if you are already faced with repower decision, the choice is an incremental one and for a new build where you are already faced with choices on power plant, supplemental wind/solar, genset etc I'd argue that its not even worth the discussion......go electric drive with diesel genset, solar or wind and be done with it.

[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.