Electric trolling motor vs 7.5 hp outboard

[jrale]

Gentlemen,

Is there a possibility that I could use an electric trolling motor vs a 7.5 hp outboard to propel my 25 ft. sailboat out of and into marinas and ocean lanes? If so, then how much thrust would I need to equal 7.5 hp? Is this feasible?
Respectfully,
jrale

 

[seaStan]

Greetings,
I had a 42 lb thrust electric motor on a 18 ft boat which worked fine until a storm came up and almost put me into a rock seawall. I didn't have enough power to pull away could only turn into the wind and barely hold position with full power. Lucky for me, the storm passed over before by battery went dead. This was about the closest i've been to wrecking my boat/.
Larger multi horsepower electric motors require at least a 24 volt battery system and use a lot of power. Hope this helps.

 

[doehunter]

I googled outboard motor thrust and found this:
http://ezinearticles.com/?Choosing-an-Outboard-Motor-For-Your-Dinghy&id=2008077

They tested several small outboards on a 12 ft inflatable dinghy.
the Mercury 3.5 hp motor put out 90 lbs of thrust.
Most people seem to like motors in the 5-10 hp range on 25-26 ft sailboats, So I would think you would be really disappointed with an electric trolling motor.
As stated above, in a pinch when your boat and your lives might depend on it, I wouldn't scrimp on power.
Jim

 

[Justin_NSA]

I don't know much about these but the Torqeedo is supposed to be an electric alternative. They make one that supposedly has the equivalent thrust of a 9.9. YMMV

 

[MrMikey64]

I don't know much about these but the Torqeedo is supposed to be an electric alternative. They make one that supposedly has the equivalent thrust of a 9.9. YMMV

Nice!! Kinda hard to justify the $4K price tag, though.

 

[Sumner]

...Is there a possibility that I could use an electric trolling motor ...to propel my 25 ft. sailboat out of and into marinas and ocean lanes? ...

I think the key thing there is "ocean lanes".

If you lake sailed and day sailed and knew pretty much what the weather was going to be that day then you might be fine getting in and out of the marina.

If you stay out multiple days and don't know what you might be facing wind/weather wise I wouldn't do it.

Likewise if I was dealing with tide/currents in and near the ocean I again wouldn't do it.

We bought a long shaft 5 HP Nissan for our dinghy, but also as a backup for the Mac and we used it on the Mac once and it did find into 20+ mph winds, but the average trolling motor isn't going to have the same thrust as the 5 HP and we had changed to a higher thrust prop also.

Since we wanted something lighter to make putting the outboard on and off the dinghy on the water we are about to buy a 3 1/2 HP Tohatsu that is also a long shaft. There again it will be a backup to the 9.8 HP Tohatsu on the Mac, but used primarily on the dinghy. I think in a situation where the larger Tohatsu might have a problem that the 3 1/2 will get us back, but there again I wouldn't buy it as the main outboard for the Mac. I would use the 4-5-6 HP models with the proper prop if electric start wasn't a criteria for you.

For us now electric start is a safety feature we won't be without for where we sail and for how long we are out. We feel that it is imperative that both of us can start the outboard in an emergency.

Good luck,

Sum

Our Trips to Lake Powell, UT - Kootenay Lake, Canada - Priest Lake, ID

Our Mac Pages

Mac-Venture Links

 

[rgranger]

I've done it!

Two boats ago, I owned a Coronado 23'. And I put two minnkota 65# thrust motors off of the back (one on either side of the tiller). Most days I only needed one in the water but I had two just in case.

It worked great and I could push the boat at hull speed with the motors set at #4 (#5 was the highest setting)

Here are some things to consider.

1) Two minnkotas is much cheaper than a 9.9 Honda 4-stroke... but you will need the riptide model minnkotas if you want to use them in salt water and they are more expensive. So you won't save as much.
2) You will want at least 4 batteries in your bank. And they add weight. But maybe a good thing if you can secure them low in the boat.
3) All of my electric motor experience has been in a lake. So I can't give you first hand knowledge of how it might work in a 30 k wind with currents to tend with.
4) You will need a way to recharge the batteries and batteries take time to charge. If you are going on longer cruises that could be a down side.

In my situation I was only sailing on weekends and had a trickle charger solar panel. That worked fine and the batteries were always topped off when I came back to the boat the next Friday.

On the plus side the silent nature of electric motors is awesome.

Quiz: My Coronado 23' was a sailboat with electric motors and a solar panel for charging the batteries. I named the boat "The delta G". Any science nerds out there get the joke?

 

[mccauley13]

The Delta G, or Thor-Delta G was an American expendable launch system used to launch two biological research satellites in 1966 and 1967. Just in case you wanted to know.

 

[rgranger]

Didn't know that one.... In my case "G" represents the thermodynamic quantity called Gibb's Free Energy.... and delta is used in thermodynamics to represent " a change in"

So from a thermodynamics point of view... my boat was named.... "A change in free energy".



This was on the stern

 

[JVB]

I used a 55 pound thrust Minn Kota on my previous boat, a MacGregor 26-D. It seemed to me to be about equivalent to a 2 hp gas engine. It was OK for getting to and from my trailer in sheltered water with no current. I went back to my 10 hp gas as soon as it was repaired.

 

[patrickfarley]

Re: Electric trolling motor vs 7.5 hp outboard Top

Mercury 3.6 is not enough. I remade the motor mount for the trolling motor and use both an electric 42 pound thrust and a 5hp outboard. The 5hp moves me quickly and the electric is for short moves, rafting up to other boats on the lake and at the dock. It is nice to be able to pull up to the dock and just maintain the position as if I am already tied up while I wait for crew(usually my daughters) to step off and grab a line in a big wind. The electric is silent and lowers the stress level.

 

[timebandit]

NO.

Gentlemen,

Is there a possibility that I could use an electric trolling motor vs a 7.5 hp outboard to propel my 25 ft. sailboat out of and into marinas and ocean lanes? If so, then how much thrust would I need to equal 7.5 hp? Is this feasible?
Respectfully,
jrale

 

[MrBill_FLL]

IIRC, GaryM is using one on the trailersailor board. -he loves it. 24V I think.

-I think it depends on where you sail, and the conditions. most of the time I think you would be ok. But when you really really needed the power, you'd be in trouble, and need help.


So, do you feel lucky?

are you looking to save money or want the quiet a electric offers.
if its the money, is your crew and your boats safety where you want to save a dollar?

 

[kevinnem]

Quiz: My Coronado 23' was a sailboat with electric motors and a solar panel for charging the batteries. I named the boat "The delta G". Any science nerds out there get the joke?

In electrical world there is the standard single phase power we all know (often erroneously refereed to as 2 phase), and 3 phase. (also a 4 phase, and a few others, but they are BIG power).

In 3 phase you have 3 hots, a neutral and ground.

You can have a set up that is either "Y" or "delta".

I preport that you named the boats such "delta-g" because it is a 3 phase- corner grounded-delta electrical system,- IE, delta-g.

Do I win?

 

[sailguy40]

As someone who has used both electric and gas, I say it all depends on where you use it. If you go out offshore and you have wind and waves, you should have your sails up. If it is not too windy, the electric can push the boat as long as you don't have current. Problem, no taking your boat out too far on calm days and if you are far out there and the wind dies, you have to wait it out. Also a downside I find is that your range is very limited with electric power. So you won't want to run it full all the time, in fact never run it full unless you absolutely need to. It will drain your battery very quick on full! So power it up just enough to keep control and get you moving. You never know when you will need to run it full so no reason to crank it up when not needed and drain your battery. Another downside about those electrics is when it comes time to drop your sails and go in, you could have a problem if the winds are high. Not to mention docking and departing with strong winds.

Positives about the electrics... nearly zero maintenance, very cheap, quiet and uses no gas. More positive is super lightweight so you can take it on or off the boat with only one hand. Oh and another thing they are extremely reliable. All you need is a good battery with enough charge and motor comes on.

Indeed, gas outboards are powerful but maintenance is expensive and frustrating at times. For example, my Nissan 9.8 is in the shop and has been in the shop for nearly 4 weeks now. First they tell me $75 an hour, take about hour and a half to do a annual service. Then they call me and say $365 to replace the water pump, engine is overheating. Next call, they say $765 because there is some corrosion in the lower unit which needs to be all cleaned out. Welcome to outboard motor ownship I suppose. I have to get it serviced because I want it running great and in top shape.

I think the Torqeedo that someone mentioned here is the way to go but those are just very expensive. Those are an actual electric outboard, not a trolling motor and they are pretty powerful.

 

[Irishguy]

I am certainly no expert. We have only sailed our Venture 25 a few times and are still learning. However I will say this: There is no way I would venture out in our sail boat with just a trolling motor on it.

The first day we took ours out the weather suddenly changed and the wind started blowing very hard. We, being inexperienced greenhorns want to get our boat back into the harbor. It was difficult to simply get our boat turned into the strong wind which was coming from the direction of the harbor. I simply cranked down on the throttle of our 10 horsepower Honda and she brought us back safely. I doubt a trolling motor could have brought us back in that wind.

There is no way I would even consider just having a trolling motor.

 

[drmyy]

How big of a trolling motor? How many batteries? How will you keep them charged. Do you have a storm jib and reefable main? It is very possible to repower a displacement hull with electrics but you need to think through you choices and purpose.