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i am doing research on setting up an electric inboard for my cal 27. i am checking around on DIY electric car blogs and any other places i think i may find useful info. if i use a forklift or golf cart motor, i am looking at around $400 to $500 for a motor. i want to try to find less expensive options.

one option i am considering is trolling motors. i have seen good used ones going for $100 to $150. i thnk one might be a good motor to convert for use with my shaft and prop. the big problem is that they are rated by thrust and not hp or kw. i can't seem to find any distributors or manufacturers that tell you the amps so, i can't calculare hp.

i am concerned that they may not have the same actually hp as another motor rated for the same size boat. they usually have no real length of shaft to turn and they have props specifially designed for them. minn kota says their props are designed for maxacceleration, not max speed, and they say their motors top out at around 5kt....that a bigger motor will just get you there faster.

so, my worry is that, although they will push a boat of a given size as they are set up, they may not have the power to turn my shaft and prop and get similar performance.

so, i was wondering if anyone had experience with trolling motors and could fill in the information gaps. i am considering something with between 60 and 80 pounds of thrust, which should push my boat ( according to the charts). if i could find someont that could give me a good idea of the amps, for such a motor, i could figure out an approximate hp number to decide if the trolling motor option, for an inboard set up, is worth a try.

or, perhaps, other motor options that i haven't considered. lots of things use electric motors. i need between 6hp and 10 hp.

any information would be helpful. thanks.
 

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Corsair 24
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well bud no trolling motor comes in 10hp at least not that I am aware of and then its torqueedo motors that cost a gazillion

for you you have options...you are small and light...a trolling motor nice and deep woukd be another feasible option among the ones you already have contemplated

good luck

Ive only been on small dinghies with trolling motors and am contemplating one right now as my dink for the main ship
 

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Electric outboards are available with over 100 hp at the upper end - but not in this application.

50 lbs of thrust in an electric translates to about 3/4 hp at the shaft. I cannot see how you could effectively use one. They are not designed for moving a heavy sailboat, but for much lighter smaller boats. Minn Kota is 12 volts up to 55 lbs, 24 volts for 80 lbs and 36 volts for 101 lbs of thrust.
 

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snake charmer, cat herder
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try torqueedo. i have an electric ob motor...torqueedo t 1003 s.... even tells you when you will be needing to recharge, and new they come with a spare battery and solar as well as 120v charging and instructions all for 1800ish dollars us... look online.. T O R Q U E E D O

yes i have seen others using, one was a 30ish ft sloop as main engine as well as outboard.
i am cruising, with a slight glitch as engine failed here in pair a dice.
 

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By the time you get to one horsepower in a trolling motor you are looking at more than the other proven to work motors are going to cost you. What gets really expense with projects like this, is not the price of the parts you use, but the wasted money and time on stuff that does not work. Sure you may look at one guy who got his system working for only $2000 but how much cash and time did he waste with stuff that did not work? I would look into systems that were done successfully and not try to reinvent the wheel, this has been done before. I doubt you will ever see 5 knots with an electric motor, unless you only want range to be rated in seconds.

Not trying to be a downer, but if 400 to 500 is a lot for the base motor, I think it is more reasonable to look into putting an outboard on the boat. I am not anti electric power on a boat, it is just that it is only good for a few people who want to use it to get on and off a mooring. It does not give you much range, unless you spend some serious money on batteries. I sail on a boat with one, and it is nice that it is quiet, but I get nervous thinking that once you get a bit away from the dock you might quickly get out of range of the batteries. And they have 12 big very expensive batteries. What happens if you have a rigging issue and can't sail back?
 

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snake charmer, cat herder
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as for electric propulsion in boats.... if you do it well you have something.there is a formosa/ct 41 in golfo de california with electric propulsion and it works quite well.
there is a 30-34 ft sloop with torqueedo propulsion, t 1003s, and they are happy as lil piggies in muck.
there is no reason to avoid electric propulsion.. just be smart and research well before going off half cocked into wtf ville....can truly become `pricey
is why the torqueedo is over all less pricey.-.you dont have to mess with it.

i have yet to see ANYONE out here using the lil cheepo trolling motors. they just dont work very long.
 

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Just as a reference my 55lb thrust minnkota electric trolling motor pushes me 2.5mph with no wind but as soon as you add a little wind and chop that drops in half. light 26ft trailer sailor.
 

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baDumbumbum
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Electric outboards are available with over 100 hp at the upper end - but not in this application.

50 lbs of thrust in an electric translates to about 3/4 hp at the shaft. I cannot see how you could effectively use one. They are not designed for moving a heavy sailboat, but for much lighter smaller boats. Minn Kota is 12 volts up to 55 lbs, 24 volts for 80 lbs and 36 volts for 101 lbs of thrust.
Yep. That's about what out Motorguide 45# troller is worth -- 3/4hp. It moves our 1400# SJ21 along at 3kts; good for maybe 3.4kts at WOT on flat water. Pretty marginal with any sort of crosswind or strong headwind or waves. It's a digital salt-water model, so it has better range than cheaper trolling motors: we can get about 3 hrs out of a fully-charged Group27 at cruising speed.

Something like that might move a C27 in and out of its slip in reliably calm conditions. That's all it would do. Be aware that fuses, wire runs, and batteries will more than eat up any savings over a small used outboard. It was still the best solution for our little boat, but there is still no electric substitute for the power density of petroleum.

We're considering Torqueedo for the dink on the big boat, however. Want to wait for more battery life data to come in.:)
 

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The problem with electric is you can't wave somebody down and bum a gallon of 12 volt off them. We use a trolling motor for our dinghy. I love it. quiet and easy, sneak up on the dock or the egrets. But, after a week of cruising, the dinghy battery is spent and I can't just dump another gallon into the battery. I could't imagine being 5 miles out and out of juice.
 

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The problem with electric is you can't wave somebody down and bum a gallon of 12 volt off them. We use a trolling motor for our dinghy. I love it. quiet and easy, sneak up on the dock or the egrets. But, after a week of cruising, the dinghy battery is spent and I can't just dump another gallon into the battery. I could't imagine being 5 miles out and out of juice.
Yes, batteries have to come a long way before it is practical in more than a very local day sailor. I doubt he his planning on cruising with it. I think a smart addition to the system is an unlimited towing package! This should be factored into the system as a basic expense. Biggest problem is you have to double the battery size to be able to not over draw down the batteries and have decent battery life.
 

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(snip) if i use a forklift or golf cart motor, i am looking at around $400 to $500 for a motor. i want to try to find less expensive options.

one option i am considering is trolling motors. i have seen good used ones going for $100 to $150. i thnk one might be a good motor to convert for use with my shaft and prop. (snip)
I think some replies missed this last sentence. There is absolutely no way you can get a typical trolling motor to turn your existing shaft and prop with enough RPMs to get out of your own way. The torque required to turn your existing prop shaft requires a reduction gear (or sheaves) on motors many times the size of a trollling motor.

As to cost, if $400 for a golf cart motor is too much, you probably need to forget about the whole project. The batteries alone will cost more than that (likely 2 or 3 times as much - you need at least a 36 volt system), and you're going to need a speed control, as well, not to mention heavy gauge cables, expensive high-ampreage fuses, etc.

Search youtube, there are quite a few videos on there from guys who've successfully completed such conversions, and I can't remember seeing any that didn't spend several boat bucks doing it.
 

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Fisher motorsailor
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I got one around 50 lbs thrust which I tried on my Avon inflatable. It gave about 3 knots and ran the battery down in just about five minutes - a small 40 AH battery that I was using just to see if it all worked. Since then it has been in the shed. I can't see any way you could use these cheap trolling motors on a boat your size.
 

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guys he said TROLLING MOTOR

trolling motors are low hp...I think the biggest is what 4-5hp?


cost is a major factor

captain already has many threads on alternate propulsion, his rebuild cal 27 thread and the inboard outboard replacement thread

like my electric propulsion for an islander 36 thread all this stuff gets lost in translation

captain if you can find the biggest trolling motor you can find for cheap, it will work

just not fast

torqueedos are awesome but so are brand new yamaha 15hp enduro outboards...

they are also not cheap by any means...

now electric inboard thats still my dream...Ill save up...for now its outboard....
 
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I got one around 50 lbs thrust which I tried on my Avon inflatable. It gave about 3 knots and ran the battery down in just about five minutes - a small 40 AH battery that I was using just to see if it all worked. Since then it has been in the shed. I can't see any way you could use these cheap trolling motors on a boat your size.
Thread drift, but there is something wrong with that. Maybe the battery is on its last legs and has little capacity.

I have a Minn Kota 55 lb thrust Riptide on my 8' inflatable and use a 76 AH battery. I have used it for many hours at a time, and use full throttle on many occasions. I have never run out of power on even multi-hour outings.

Don

This is what you need - the ultimate electric powered dinghy.



This is not my boat but the one I got the idea from. I am doing the same thing with a 50 watt panel on a simpler bracket. The solar controller is installed in the lid of the battery box - I used an Agm battery so it won't corrode the controller.

I am a proponent of electric drive - when it makes sense. On a larger boat it only makes sense if you can plug in at night - in other words day sailing only. Battery technology and recharge just isn't there yet. And it is not a low cost option anyway. One gallon of diesel equals almost 900 lbs of batteries using common batteries - flooded, gel, or agm. A small diesel or outboard depending on the boat size is a better choice - both in practicality and in dollars.
 

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Discussion Starter #18
There is an electric cal 27 on craigslist SF Bay , you could email the owner and see what he did.
really!? thanks. i'll do that.
 

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Discussion Starter #19
well bud no trolling motor comes in 10hp at least not that I am aware of and then its torqueedo motors that cost a gazillion

for you you have options...you are small and light...a trolling motor nice and deep woukd be another feasible option among the ones you already have contemplated

good luck

Ive only been on small dinghies with trolling motors and am contemplating one right now as my dink for the main ship
yeah. see. that's my question. see, they don't don't give HP ratings for trolling motors. they just give thrust. however, minn kota lists an 80 pound thrust motor that is good for a 25 foot boat. my boat is only 22.34 LWL. so, how does that work? how many HP is 80 pounds of thrust? if it will power my boat on the transom can it be used as an inboard? i'm just checking out any options there may be.

i had considered just getting a trolling motor, in the beginning, but everyone said it would never work.
 

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Discussion Starter #20
try torqueedo. i have an electric ob motor...torqueedo t 1003 s.... even tells you when you will be needing to recharge, and new they come with a spare battery and solar as well as 120v charging and instructions all for 1800ish dollars us... look online.. T O R Q U E E D O

yes i have seen others using, one was a 30ish ft sloop as main engine as well as outboard.
i am cruising, with a slight glitch as engine failed here in pair a dice.
waaaaaaay too salty. i could get a ready made electric inboard system for just a little more than that.
 
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