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trolling motors

Started by mrbill, June 27, 2007, 12:49:46 PM

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mrbill

Does anyone have any experience using a trolling motor to propel a small inflatable? I have a 6' Achilles as a tender which I row now...but very hard if there are two people aboard! Has anyone used a salt water trolling motor like the Minnkota Riptide 12V motors using a battery jumpstarter pack as a power source. My needs, and distances to cross, are small, but will a jumpstart pack be powerful enough or have enough endurance?

Leroy - Gulf 29

Thanks for this post - I have the same thing.  IIRC on the TSBB, Charles Brennan said that a small jump start pack would work, but not for long distances.

Fortis

Yep. It is the standard outboard for our Bombard inflatable. Ours is a 34pound thrust unit and works a treat. The charger battery you propose is all wrong though.

Gte a proper AGM battery of about 40AH minimum. It gives you an hour and a bit of motor time and the power to use an electric inflator/deflator for the boat.

I now use two of these batteries built into a case that started life as an airport luggage wheely-case...it makes an excellent seat once in place and also holds any other items you want to keep dry. The two batteries give me a really good range for going exploring up little rivers and creeks. Fun stuff.

The best things about the electric trolling motors is the silence of operation,(actually quieter then rowing), the hassle free way you can just throw them intot the back of the car for six months and not have fuel smells or clogged carbi's etc, and the lightweight nature of the units because the load is broken across two "modules" (batteries and motor). My wife likes this as it means she can set everything up and pack it back down without strain or hassle.

Downsides.... Even the most powerfull of the 12volt units will still be less then a 6.5HP gas outboard. The trolling motors were devised to move big boats over short distances to just modify position for fishing....so you cannot always just run the motors flat-out for hours ata time to push your dinghy...they start to overheat and compensate by powering down and really chewing power. So it always makes sense to buy a bigger motor then you think you need and run it at 3/4power for extended dinghying. Finally, because of the reason mentioned above, most units have a prop that is optimised for pushing around a big boat slowly rather then getting a light inflatable dinghy on the plane. This is now being corrected by most trolling motor suppliers, with a choice of three or more props to be had....but then you get the minefield of trying to get "the right one" for you and end up spending extra as you buy two extra porps and play with them.

Generally speaking though. I am very pleased with ours and am shortly upgrading it to a 60pound thrust unit which has just come on the market down here.

Make sure you fit good quality Anderson Plugs for the electrical connections, nothing else works nearly as well and having salt water get into the electrical join will halve your battery running time like nobody's business.

If you are interested in extended range type exploring and fishing with the trolling motor...consider a 24volt unit. They are more powerful and more economical overall then the 12's, and you end up just hooking up your two batteries in sequence instead of parrallel. You can still charge them on a 12volt charger, you just swap the leads back over to parrallel to do it. The 24's are also currently somewhat cheaper as the tach is not being readily taken up by the boating community yet.

Hunt around. They are definately a good thing, but as with all things, some research will pay off.

Alex.
__________________________________
Being Hove to in a long gale is the most boring way of being terrified I know.  --Donald Hamilton

AdriftAtSea

I'm not a big fan of using electric trolling motors for a dinghy.  The run time on batteries is usually far less than you can get with even just a two-gallon gas can.  It would also seem to me that you're at risk of running out of power in a larger anchorage without much warning.  Finally, I think a small four-stroke, like the 3.5 HP Tohatsu that I just got is going to be easier to handle and lighter than a trolling motor and battery pack—even if you count the weight of the two-gallon gerry can with the outboard.
s/v Pretty Gee
Telstar 28 Trimaran
Yet we get to know her, love her and be loved by her.... get to know about My Life With Gee at
http://blog.dankim.com/life-with-gee
The Scoot—click to find out more

Fortis

Oh excellent! We haven't had a good disagreement in ages!

I disagree!!

The running out of power thing is actually really nice. Even on my old motor, which does not have an LED power display, you can feel when the battery starts to wind down...and in the case of my motor you then still have close to 30 minutes of half to three-quarter powering before it slows down to where it could not make headway against a 6-8knot headwind.

In my experience this is way more warning then a small petrol outboard with an enclosed tank gives you.

I have an old mercury 2.5hp 2 stroke and the 34pound trolling motor is lighter, even with ONE 44ah AGM battery. With two it is heavier, but I love the range.

Newer trolling motors DO have the little LED display that lets you have a real clue about where you are in the battery's ability to supply power.


The really GOOD trolling motor will likely be more espensive then a so-so outboard ...but there will effectively be zero service costs thereafter (until you need to swap out the batteries, in a few years). Pretty total reliability to...I get a little paranoid about pulling that bit of string when I am out on the water with a petrol engine.

Having said all that...

If you are going to go for a gas engine, tohatsu seems to be doing about the best ones right now. Kind of astounding, but there you go. Yamaha's new series is pretty good, but at close to double the price and Honda is doing nice things with noise reduction, though I hate their prop setups for small boats (they are nothing short of awsome on BIG ones though).

Alex.

P.S, for me, the other advantage of the trolling motor has been that I can use it to move the yacht around an anchorage or marina without needing to fire up the diesel engine, it was a very "polite" way of leaving a crowded marina full of sleeping people at 4.30am a couple of times.


__________________________________
Being Hove to in a long gale is the most boring way of being terrified I know.  --Donald Hamilton

mrbill

OK, so suppose I get a trolling motor...what do you use for batteries, how do you store the batteries on board, what size battery do you recommend, and how about recharging the battery. I was hoping a battery jumper pack would work, becasue they can be plugged into a 120 v outlet to recharge between uses, plus they are compact and easy to transport. I assume the vote is against jumper packs.

Parrothead

A jumper pack is for jump starting a car....wrong type of battery. You need a deep discharge type...AKA golf cart battery , trolling etc. AGM are very good for your little 8 footer because of no acid spill issues...they are pricey tho. Get a charger made for the battery type...no big expences for the small one you need. Deep discharge batterries are made to run 1000's of cycles so the batterry will last longer than a 8 ft inflateable dink. You can get the stuff you need at west marine or the auto store.

AdriftAtSea

Don't use a golf cart battery, as most GC batteries are only 6VDC... ;)
s/v Pretty Gee
Telstar 28 Trimaran
Yet we get to know her, love her and be loved by her.... get to know about My Life With Gee at
http://blog.dankim.com/life-with-gee
The Scoot—click to find out more

Parrothead

yes of course you need 2.

mrbill

OK...after further research: The smallest Minnkota trolling motor for salt water uses 30 amps/hr at full throttle. Xantrex (model 600) makes a portable power supply that delivers 28 amps. It has the advantage of being portable, and can be recharged easily (even from my engine so I can recharge it while motoring during a cruise). It has some features I don't need, like a built in radio  :) .

So you battery experts tell me: I'm guessing I can get about 1/2 hour of use per charge...maybe longer if I don't run at full throttle.

They apepar to cost about $230 each, but are widely available a discounts of up to half that.

Will this work?

AdriftAtSea

Personally, I think you'll be better off with a 12 VDC battery.  Even a Group 22 AGM battery would provide about the same amount of power at half the cost. It'll probably handle the high drain use better than the Xantrex will as well. A Group 24 AGM like this one will provide more power and cost less.
s/v Pretty Gee
Telstar 28 Trimaran
Yet we get to know her, love her and be loved by her.... get to know about My Life With Gee at
http://blog.dankim.com/life-with-gee
The Scoot—click to find out more