outboard alternative

Ross · Feb 16, 2010

I read once somewhere that sustaining 10 pounds of thrust with paddles is about the liimit for a kayaker. But paddles are more efficient than propellers.

caguy · Feb 16, 2010

I have the Minn Kota 28 and it work just fine. You won't be able to go great distances but it will get you to shore. I ran mine up and down the channel at MDR with about a 12-15 knt head wind and it still made some pretty good speed, and that was with just a battery jumper battery. I video taped it but can't find the file now. The nice thing about it is that it stores so easily and it is easy to load. The 8.5 I have for it now is a bit of an overkill but a lot of fun. What was weird about it was that the tiller throttle was backward so I would speed up when wanting to slow down and vice versa.

Tom Spohn · Feb 16, 2010

I have a Torqeedo electric motor on my 10' Zodiac. It pushes the boat at about 3 knots cruise and 4.6 knots top speed for very short periods. It develops about 68 lbs of thrust which is 2.1 times what the trolling motor develops. I don't know if the math works but I would estimate you would go at about 1.5 knots.

sailingdog · Feb 16, 2010

the one caveat I'd have is that you'll have fairly limited range with that and no way to easily recharge it; so keep the oars handy...

tommays · Feb 17, 2010

Just be sure its a saltwater unit as the freshwater units will fail pretty fast

waverider · Feb 17, 2010

You will not be able to use it in high wind conditions, it will go faster then rowing in light winds and small waves.

sailaway78 · Feb 17, 2010

Short Range

Unless you load the dink up with a couple of large deep cycle batteries, your range will be limited. And the batteries are heavy. If you only need it for short distances, and have a good way to recharge should work fine. Small outboards on ebay are pretty cheap also.

Benny · Feb 17, 2010

It will work very well in mild conditions but do not attempt to fight wind or current. Years ago I had an old motorcycle battery which refused to die with all the abuse of being deep cycled and a 20 lb thrust motor and it worked very well to get to and from shore (200 yds) in a protected basin. The battery finally died after left unused for over a year.

sailingdog · Feb 17, 2010

Of course, the advantage of a small outboard is that they're very easy to "recharge"... with a jerry can of fuel along. A Tohatsu 3.5 HP engine is light, about 40 lbs. with fuel, add a 2 gallon jerry can, and you can run for almost NINE hours. The batteries to give you a couple of hours of run time on a trolling motor are probably heavier than that.

Nice N Easy said:
Unless you load the dink up with a couple of large deep cycle batteries, your range will be limited. And the batteries are heavy. If you only need it for short distances, and have a good way to recharge should work fine. Small outboards on ebay are pretty cheap also.

MrBee · Feb 17, 2010

For a dingy I would look for a small Outboard. something in the range of 2 - 4 hp. Also that size motor will have the fuel tank integral to the motor so nothing extra to move around, just a motor. The motor alone would weigh less than a battery for the electric motor. Yes it would be a bit noisier but... Everything is a compromise. for a couple hundred or less you can get a small outboard. I never had one but the "Cruise and Carry" seems popular and they are regularly on ebay.

Brian

Prime Time · Feb 17, 2010

Amp draw

I have an electric trolling motor that I have used on my Flying Scot. It moved us just fine. The outboard literature should tell you how many amps it draws at different settings.
From that you can figure out roughly how long you can run in minutes based on the amp hours of the battery. Of course, the amp hours are calculated with a specific load. Calder's book has a table I think on this topic.

Dan Johnson · Feb 18, 2010

Manny...

almost all the guys in my marina that tried electric trolling motors on their dinks have given them up for a low hp gas engine. Wind and waves work against them as the charge runs down--batteries are heavy and go straight to the bottom if the dink gets tipped!

druid · Feb 18, 2010

tommays said:
Just be sure its a saltwater unit as the freshwater units will fail pretty fast

This has not been my experience. I've been using a Minn Kota 40-lb for over 5 years in the salt and the only harm is a bit of corrosion on the aluminum housing which made the paint fleck off. A wire brush, some sandpaper and black spray-paint and good as new!

A 28lb is a bit "light" - I find the 40-lb adequate for getting to the shore from anchor or putting around the bay. I can charge the battery either off the engine's alternator, the AC charger, or a solar panel - no need to carry gas! And the battery and motor are WAY easier to store than a gas outboard and fuel.

One of my biggest peeves is in a quiet anchorage, when the loudest noise even the big powerboats make is the anchor-chain, then you hear WWWAAAAAAAAAAAAA from the outboard on the dinghy (and this is often at midnight when the crew is returning from the bar...). Give me electric ANY day.

druid
"Coatue" Crown 28

Quoddy · Feb 19, 2010

Quiet and clean

We have had a good experience using electric for our tender. There is a lot to be said for quiet, no fume, start every time, no maintenance, light weight, no carbon propulsion.
We have been using a 30lb fresh water electric with 30ah AGM on a 8 foot Zodiac with one person aboard for 4 years. Our mooring is 430 yards from the dock in a fairly open mooring field so wind and current can be issues. With a starting voltage of 12.5v you can go about a mile at 2.4mph. We recharge at home with solar panels to make it zero emission.
Things to consider: A rapid draw on such a small battery, even if it is a AGM,which can tolerate it, will pull it down quickly with a correspondingly rapid rebound.
With 30lbs I have not lost headway, but 15k of head wind would certainly be a challenge.
Fresh water model is stainless and plastic so with care I’m hoping it won’t be a problem. I froze the tension screw by not paying attention.
Speed is a huge factor in range so low speeds are best. If the motor is not a modern digitally controlled model then speed is controlled by resistance so going slower does no good. Ours is the old style.
As you can see even with a less than perfect system it can work great for the type of use I am putting it to. For greater versatility, which I am heading to, I would say a higher thrust digitally controlled, still a fresh water model for the price, with a larger battery( or two battery system ,one in backup) may be the way to go. The latest addition to the system is a Battery Bug which is supposed to continuously monitor battery condition.

Stu Jackson · Feb 19, 2010

Elec dinghy motors

The one missing link in these discussions is how you use your dinghies. Since distance is part of the equation, in addition to speed and endurance, please tell us how you use yours.

For instance, where we use our dinghy can be mixed on any given weekend. One: short hops to shore at an anchorage or mooring field, maybe 200 yards two or three times a day for the two or three days of a weekend. However, we sometimes like to go out for breakfast, which is at least a five minute dinghy ride at "top speed" on a 10.2 Zodiac with a 9.9 HP engine. I doubt an electric motor would work for our intended usage.

When we had our old 8'-4" dinghy with a 1.2 HP motor, we simply couldn't make that breakfast trip.

So help us understand how you use the motors since one size doesn't fit all.

The quiet of elec motors is nice, but I don't mind dinghy noises after I awake, and when down below can't recall ever being awakened or kept awake by a dinghy engine. We don't sleep in the cockpit (it's too cold here - or too hot in the Delta).