Electric motor hp for P-18

Started by Grambo the Gray, Sep 04, 2023, 03:21 PM

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Grambo the Gray

Just bought a P-18 and I would like to put and electric trolling motor on it to move around and exit the dock area. Based on my research a 2 hp should be good enough. Has anyone ever tried this approach?

eaglecreeksailor22

I have used a Minn Kota 50 lb thrust with a 42 inch shaft on my P165 and it moved it very well. It weights in at 750 lbs plus misc onboard, I guess 1000 lbs total. Minn Kota claims you will need 2 lbs thrust per 100 lbs of weight. I only had about 1/4 mile from the dock to open water and it took about 20 minutes each way. The 100 amp hour marine battery was supposed to last 1.5 hours with the motor on the highest setting. I also used a 20 watt solar panel to maintain the battery.  It makes a pretty inexpensive package that works quite well compared to the $3000 Torquetta"s
{spelling}.

Rich

pgandw

The Epropulsion Spirit 1.0+ cost me $2559 before sales tax this July.  Epropulsion rates the Spirit as equivalent to a 3hp gas outboard, and I agree with them, having previous had a 5hp gas outboard.  Spirit has 1hr 15 min at full throttle which has little use on my boat.  On my 19ft Mariner I get 4.5kts at half throttle (checked with my GPS) with 2.5hrs run time.  Normally use 300-400 watts for motoring at 3.5-4.0 kts, giving a range of 12+nm and 3.5-4hrs run time.  Perfect fit for my Mariner, all the power I need with a reasonable range.  Does cost though, more than half the value of the boat.

But the motor got me out of the doghouse with the wife, who was complaining I never used the sailboat.  She was right, I had a hard-learned anxiety about whether or not that gas outboard would start when I wanted/needed it to.  I started out with range anxiety with the Spirit, but a 3 day cruise from Niantic, CT to Mystic CT and back proved it had enough power to handle the 3-4 knot tidal currents against me at the railroad bridge on the Niantic River, and still had enough range to power 6 miles in the Niantic and Mystic Rivers, with 50% battery left at the end of each day.  Similar results here in NC motoring 6.2 miles from the launch ramp to home dock in 1hr 29 min.  Recharged battery each evening.

Fred W
Stuart Mariner 19 #4133  Sweet P
Yeopim Creek, Albemarle Sound, NC

tjspiel

#3
Quote from: Grambo the Gray on Sep 04, 2023, 03:21 PMJust bought a P-18 and I would like to put and electric trolling motor on it to move around and exit the dock area. Based on my research a 2 hp should be good enough. Has anyone ever tried this approach?

Just based on what I've heard other people say, a 2 hp outboard should be enough to get a P18 up to hull speed.

But trolling motors aren't designed for speed and they are usually sized in terms of pounds of thrust rather than horsepower. They are meant for moving boats slowly. So you'd need a fairly large trolling motor to get the equivalent of 2 HP and you're probably need a 36 volt system or 3 twelve volt batteries.

But if all you need it for is moving around and exiting a dock area, you don't need to move at hull speed and a trolling motor will likely serve you well. They're very reliable and require little maintenance. If your boat is in a slip or on a mooring, install a solar panel to keep the battery charged and life will be easy. :)

My boat is on an electric only lake. Sailboats are limited to 22 ft in size and everyone (myself included) uses trolling motors if they have motors at all.

But we do not need to worry about tides or currents. That can make a big difference.

I've had a 40 lb thrust Minn Kota on my P-18 for about 3 seasons and I'd describe it as adequate. When I was trying to tow another boat against a heavy wind a few weeks ago I could barely make any headway with it.

Even though those were unusual circumstances, I still decided it was time to upgrade to a 50 lb thrust motor. 55 lb is about the limit for a 12 volt system.

If you're going to be motoring long distances out in open water, I'd not recommend a trolling motor. But for what I use a motor for and for what you're describing, they work really well.

You start them by twisting the tiller handle. Twist the other way and you're in reverse. No spinning the motor around. No reaching back for a lever. No annoying engine drone grinding on your nerves or making conversation difficult.

tjspiel

Quote from: pgandw on Sep 04, 2023, 07:44 PMThe Epropulsion Spirit 1.0+ cost me $2559 before sales tax this July.  Epropulsion rates the Spirit as equivalent to a 3hp gas outboard, and I agree with them, having previous had a 5hp gas outboard.  Spirit has 1hr 15 min at full throttle which has little use on my boat.  On my 19ft Mariner I get 4.5kts at half throttle (checked with my GPS) with 2.5hrs run time.  Normally use 300-400 watts for motoring at 3.5-4.0 kts, giving a range of 12+nm and 3.5-4hrs run time.  Perfect fit for my Mariner, all the power I need with a reasonable range.  Does cost though, more than half the value of the boat.

But the motor got me out of the doghouse with the wife, who was complaining I never used the sailboat.  She was right, I had a hard-learned anxiety about whether or not that gas outboard would start when I wanted/needed it to.  I started out with range anxiety with the Spirit, but a 3 day cruise from Niantic, CT to Mystic CT and back proved it had enough power to handle the 3-4 knot tidal currents against me at the railroad bridge on the Niantic River, and still had enough range to power 6 miles in the Niantic and Mystic Rivers, with 50% battery left at the end of each day.  Similar results here in NC motoring 6.2 miles from the launch ramp to home dock in 1hr 29 min.  Recharged battery each evening.

Fred W
Stuart Mariner 19 #4133  Sweet P
Yeopim Creek, Albemarle Sound, NC

If I had more demanding needs of an outboard (and had more money), I'd be tempted by the ePropulsion. I've heard those can be re-charged (at least a little) by the boat spinning the prop as you move through the water. Is that true?

I agree with you on the fussiness of gas motors. They can be very reliable if well maintained and you use them often enough to know their individual quirks, - which they all seem to have or develop over time. :)

This past Spring I went sailing in Croatia with a large group of people on 4 boats. One decision we had to make was whether or not we wanted to pay a little extra money to have outboards on our tenders. Even though we'd never going more than a short distance in them, I was outvoted and we all got them.

My experience with those abused outboards on charter boat tenders has not been good and Croatia was no exception. 3 of the 4 little Suzukis experienced serious problems starting and two were practically worthless. Not only did it take forever to get them started and they'd stall within 5 minutes. Not worth the hassle.

Brian N.

I think Tom gave you some great info, and agree that a 50-55lb thrust 12 volt system might be a great choice. Gas engines are great work horses, but require feeding and care.
Fair winds
Brian N.

Bruce Mason

Quote from: tjspiel on Sep 04, 2023, 09:14 PMI've heard those can be re-charged (at least a little) by the boat spinning the prop as you move through the water. Is that true?

The Spirit 1.0 Plus EVO does have hydrogeneration, the 1.0 Plus doesn't. It starts at 4 kts (50W), and isn't really significant until around 6 kts (140W). At 10 kts (360W), the hydrogeneration cuts off to protect the system. So, if you can sail for extended stretches at 6+ kts it could be useful, if the drag from the system is acceptable.

The British dealer Nestaway does a good job comparing the Torqeedo 1103 and Spirit models. They sell both. Scroll down for their thoughts on the EVO hydrogeneration.
https://nestawayboats.com/shop/epropulsion-spirit-plus-1kw-electric-outboard/
Aroo, PC 308
Narragansett Bay, RI

Straander

Hello Grambo. I recently upgraded my P165 to a Newport Vessels 86lb thrust trolling motor ($250) and a 100ah 24v LiFPO4 battery ($630). After a outing this spring, I  had decided that my 12V, 62lb thrust motor just wasnt cutting it. The new system is working out for me well so far, can get close to 4knots in calm flat water, and can still make a little headway against wind and significant waves as I found out last sunday. Still, not what id want to count on for main propulsion if I was out in the ocean though.

One annoyance with these trolling motors is that they're made to push a heavy load slowly, so going overboard on lbs-thrust gives only minimal speed increases in lighter, efficient hull designs like these sailboats. I measured the current draw when at speed and it was only about 2/3 of what the motors max rated current draw was listed at, implying I was leaving a lot of power on the table. I wish the companies would offer higher-pitch propellers for them for usages like ours.

Quote from: Grambo the Gray on Sep 04, 2023, 03:21 PMJust bought a P-18 and I would like to put and electric trolling motor on it to move around and exit the dock area. Based on my research a 2 hp should be good enough. Has anyone ever tried this approach?
Vessel: Precision 165 "Irresolute"
Home Waters: Coastal Washington

noelH

Torqeedo, EPropulsion, Temo.... Plus probably more choices for electric boat motors.  Torqueedo Travel user for the past 6 seasons.  Overkill for my needs.  Just to get in and out of the marina.  Temo has an interesting 450 watt motor. Looks like a stick with a prop at the end. Transom quick attach mounting plate turns it into a more "proper" motor.  Light at ~5kg total mass. Not a boatload of thrust.  In one video review it was able to push a dinghy at ~2kts is gentle choppy seas.  They have a model that caught my interest that is in the same class as the Travel and Spirit.  The features I liked about it was a height adjustable shaft.  No need to choose between a long or short shaft. The motor in the kicked up position can be rotated 180 degrees for easy removal from within the cockpit.  Even with the battery and tiller removed from the Travel it is a pita to remove in anything but calm seas.

A seasonal resident trailer sailor just purchased a EPropulsion electric.  His boat has a motor well.  Originally was looking at the Torqeedo Cruise, but the EPro Spirit meets his needs. Plenty of power to move his +20 footer in and out of the marina. He was using a MKota trolling motor, but got tired of dealing with a lead acid battery and the very limited capacity.   
Sage S15
 Vela

Bruce Mason

In addition to news of new developments in marine electric propulsion in general, Plugboats puts out some guides that might be useful, especially the Less than 5kW and Trolling Motor versions.
https://plugboats.com/category/plugboats-guides/

They don't seem to include the Temo. In the Trolling Motor guide they do mention that they didn't include bow-mounted motors, but rather focused on transom-mounted ones used primarily for propulsion. The long-tail Temo design might have fallen in the "others" category. Interesting design!
Aroo, PC 308
Narragansett Bay, RI

tjspiel

Quote from: noelH on Sep 12, 2023, 11:52 AMTemo has an interesting 450 watt motor. Looks like a stick with a prop at the end. Transom quick attach mounting plate turns it into a more "proper" motor.  Light at ~5kg total mass. Not a boatload of thrust.  In one video review it was able to push a dinghy at ~2kts is gentle choppy seas.  They have a model that caught my interest that is in the same class as the Travel and Spirit.  The features I liked about it was a height adjustable shaft.  No need to choose between a long or short shaft. The motor in the kicked up position can be rotated 180 degrees for easy removal from within the cockpit.  Even with the battery and tiller removed from the Travel it is a pita to remove in anything but calm seas.

Temo is interesting but not sure it's practical for a sailboat. One thing you might want a motor for is to keep you headed into the wind as you raise/lower sails. The Temo is trigger operated, - once you let go to move forward, it stops.


noelH

#11
The Temo 1000 would be more suitable for those of us who are motor dependent to hoist and lower sail.  On light wind days I usually just more or less point the bow into the wind and rapidly as possible hoist the sail.  Only dealing with ~80 sq foot main. Easily raised from the cockpit.

Figure if Lin and Larry Pardey sailed couple time around the world without a motor there must be something I haven't figured out in hoisting and dropping a sail without a motor in stronger winds and choppy seas.  Did have to drop the sail once in strong winds without motor aid. No option. Straight-line wind of +50kts coming my way. Just turned Vela hard into the wind after dropping the jib and quickly dropped the main.  Got the last sail tie on and just hooked in before a barepole knockdown.
 
Torqeedo has a new Travel model out the 9??.  Little less money the Travel 1103C.  Same battery. I think it is marketed as equivalent to 2.5hp ICE.

Switching the battery of the Temo 1000 looks to be significantly easier than either the Travel or Spirit.  Especially under lumpy conditions. Those waterproof connections on the Travel and Spirit  are to be too easy to cross thread.  I know on the Travel careful threading even on land is required.

Temo tiller doesn't give you the data that the Travel and Spirit does. Looks like there is an indicator for low capacity, but no SOG, watts, estimate range....But I like how the tiller folds into the shaft.  I find the Travel's tiller to be at times in the way.  Vela has only a 5ft cockpit. Really only 4 functional linear feet with the rudder tiller and the motor tiller taking up space.  Space under the rudder tiller is where I stick my cooler.  So not really wasted space.

Torqeedo battery life seems to be as advertised. Better be considering the $$$$s.  My rarely used backup battery is 6 seasons old. Basically like new capacity. Have yet to notice any diminished capacity on the primary battery based on range relative to SOG. Eventually probably just replace the motor and shaft with a1103C unit if sold as a stand alone.  One thing to consider when purchasing a motor.  The back compatibility of older models. Checked with Torqeedo. They emailed me that the 1003 tiller unit and battery can be used on a 1103. The new 9?? uses the same batteries.  Not sure about the tiller unit.

Sage S15
 Vela

tjspiel

#12
One thing that makes me skittish about buying a Torqeedo or ePropulsion is the lifespan. I don't think you can count on a battery lasting more than 10 years (even if unused) or that 10 years from now you'll be able to even get a battery for a 10 year old model. Can you even buy a battery for an old Torqeedo 503 from 2016 for example?

Personally I like to purchase big ticket items on the used market and in the case of these electrics they'd have a limited lifespan left.

So I'll probably be sticking with trolling motors until there's a 3rd party replacement option for electric outboard batteries or they otherwise get much less expensive.

Or what may happen is that eventually I'll get to a point where I've only got 10 or so years left of sailing in me so what the hell. :)

pgandw

A cable to use an external battery for both the Epropulsion Spirit and Spirit EVO is available.  Needs a 48V battery - drop-in LiFePO 48V batteries are now also available. But 25AH at 48V (slightly smaller than the stock battery) still isn't cheap.

The Spirit battery is rated at 80% after 500 charge/discharge cycles.  Using the battery 50 weeks per year, you would reach 80% capacity in 10 years.  And the battery floats.  Your gas outboard is going to need a lot more maintenance than battery replacement in 10 years.

Still your choice.  If a trolling motor suffices, then don't go bigger.

Fred W

tjspiel

#14
Don't get me wrong, I really like the idea of an electric motor and would prefer it to gas. But a lithium battery degrades with time as well as charge cycles. It may be next to worthless in 10 years no matter how little you use  it. And at that point, is the motor even worth keeping or are you better off getting a new one?

A small gas engine can be fussy for sure but if you take care of them they can last for decades without much in the way of maintenance costs. I've had a snow blower for a long, long time and once I learned not put ethanol in it I've really had no trouble with it.

But eventually gas motors will be a thing of the past. There's little doubt in my mind of that.

There's a trip planned to Lake Pepin (wide spot in the Mississippi) for the second week of October. And I was looking for outboards for that since a trolling motor won't cut it. Would have probably bought a used gas engine for it because I just can't justify the cost of an electric. But as it turns out I'm going to be out of state on the same weekend so I don't need to worry about it, - at least until next year.