Electric outboards - any views?

Hazymoonshine

Hazymoonshine

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Hello,

I have just bought a 2.4m inflatable to use as a tender, and am considering buying an electric outboard to use with it. The tender will mostly be used for short trips around Solent anchorages, with the occasional river exploration (Beaulieu..)

I am mindful of the need to have a decent battery to go with it, but on the face of it it does seem a good idea.

Any thoughts, or experience would be very much appreciated.

Thank you

H
 
Expensive alternative...

I love the concept of electric outboards, but every time I look into them I end up thinking they're an expensive alternative to a nice little petrol outboard.

Electric outboards now come in 12, 24 and 36v versions - meaning at least 1, 2 or 3 batteries. I reckon 1 battery is plenty to cope with in a small inflatable, so that limits the choice to 12v outboards. The maximum thrust with a 12v outboard is about 55lbs (considerably less than 1HP). That means that in tidal streams, progress could be very slow. More importantly, if you run the outboard at the maximum 55lbs thrust, it'll draw about 45-50A, so the running time with a regular 110Ah deep cycle battery would be measured in minutes.

Also, for saltwater use you need to buy a proper saltwater electric outboard, because many of them are only designed for freshwater and will disintegrate in front of you at sea.

But the bottom line is that saltwater electric outboards aren't cheap, especially when you add the cost of the battery (and ideally you'd want a sealed or gel battery to prevent spillage problems). A nice little petrol outboard would be a much better proposition!
 
Re: Expensive alternative...

I have an electric outboard on my dinghy. Mine has 36lbs thrust and 6 speeds. Top speed is not exactly fast. A 75A/H battery (about as heavy as you would want in a small dinghy) lasts about and hour and a half on a medium speed.

The biggest advantage is how quiet they are, just a low humm instead of a noisy outboard.
 
Friend of mine has an electric "Trolling" o/board as the Americans call it ..... it is one of the higher power 12V jobs ....

It's very nice and quiet on a lake or v.slow running river ... gives about 1 - 2hrs with care. But any weather or current and it struggles ....

For use around solent areas ? I think it's a bit doubtful .... you say Beaulieu .... I think that is definitely out - the tide run can be strong ......
 
We have used a salt water electric outboard for 8 years.

It powers a 8' hard dingy and we clocked it against a yacht at 2 knots maximum. The range is limited at around 1 mile per 100Ahours. The rule is that, if you could not row the distance or current then don't expect to go by motor. I do not know how it would cope with an inflatable as they are generally harder to row.

The real problem is that when using it in an anchorage to visit someone you have to talk loudly or there is the possibility of serious embarrassing situations. Most people are only listening for outboards!! It got named the "stealth dingy".
 
Thank you all very much. There are some extremely useful points raised. Whilst I appreciate the limitations of battery capacity, I'm not sure I have a feel yet for what size would be required to drive the dinghy.... I guess Solent tidal streams (boat is top end of Portsmouth hbr) might push me towards petrol..

Thanks again, I really appreciate the guidance.

H
 
I have been using a44lb thrust elec motor on a 2.7 waveline blowup over the last few weeks and ended up buying a yahama 2.5 4stk last wk end as I was not impressed with the motor. I have had it for about 4 yrs now, and had been using it on fishing boats up to 17ft in lochs with no problem, getting up to 8hrs from a 110ah leisure batt. (obviously only using it to the top of each drift)
But Idecided to try it on the dingy, but instead of using the 110ah batt, which is too heavy for lugging in and out of the dingy and passing up to the boat at the mooring, I was using a brand new 85ah batt, which was only giving about 40 min total time before going completly flat, and that was in calm water at slack tides, I also found it could not push the dingy near as fast as 14 - 17 ft grp loch fishing boat.
I would not reccomend one, even on a dingy with an inflatable keel.
Go for a 2 or 2.5 hp 2 stk. and try to keep your outboard weight under 15kg if you can, regardless of what the dingy max engine states, the yamaha I bought last wk end is 17 kg (19 according to PBO AUG,) and the waveline is 2.7m with an inflatable keel and air floor, I found I could have done with a little more weight in the bow when I used it on sat, and that was with me sitting on the centre seat, not the side tube.
It will depend greatly on the make of your dingy, as I have noticed (after I bought my waveline) that even though the side tubes run past the transom that they start to taper to a cone right at the transom, where as some of the other more expensive ones actually continue past qiute a bit before starting to taper, which obviously gives a lot more boyancy aft of the transom, hence alowing a heavier out board to be used. Hope this is of some use to you, Good luck.
 
Electric outboards - any views?

Lots of views as you trundle along at 1 knot. Make sure you take a flask on your journey to the boat lol.
 
The giveaway is that the output of an electric outboard is always quoted in terms of thrust rather than bhp. This masks their measly power output compared with petrol type outboards. Yes, I know that 1 bhp equals 746 watts and so if you can establish the current drawn you can calculate wattage but many potential purchasers don't know this and can be misled.
 
Ah, but if you read any electric motor advertising blurb, you will find that electric motors are magically efficient, and a 3kW motor is easily able to drive a boat as fast as an 8hp engine (I actually read that one recently). OTOH, I'm not sure how many petrol outboards quote their HP at the propeller. Horsepower is a notoriously dodgy measurement to make.
Be that as it may, regarding the o/b I've got a 24lb one for getting to the mooring and back and it does that just fine. It struggles against a strong tide and in winds of F5 or more, but neither is a problem in this instance. The main advantages are the near silent running, lack of petrol smells and the fact that it nearly always starts first time. I reckon mine will go for over 2 hours on a 75Ah battery, but after that you'd have to row.
 
I once had a 'race' in inflatables with some people going from Bucklers Hard to Beaulieu village.

On the way up their electric outboard smoothly beat a combination of rowing and a knackered Evinrude 2.3 that fired every other revolution and died above tickover. They offered us a tow... (breakdown in condenser) . On the way back they were rowing slowly against the wind with a flat battery. We were still spluttering and rowing slowly.

This knackered outboard was a bit scary in Salcombe, we had to creep along the edge of the channel well uptide and then sort of drift across to the boat, grabbing on as it shot past at a couple of knots I suspect the electric outboard would need similar tactical usage.

As for the Hamble, forget engines or rowers that can do less than 3 knots.
 
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