Trolling Motor For Caper

[SpeciMan]

Just bought an electric trolling motor at a reasonable price from a second chance offer on ebay.

 

I may not use it when close inshore, but for those 2-3 mile offshore marks when the wind picks it could come in handy.

 

After mucho research went for the Minn Kota Endura 30lb thrust model. This is one of the lighter engines and has the shortest shaft of the lot being 30".

 

The one I am buying is for freshwater use. After reading users comments on this motor it should be ok for saltwater use providing it is rinsed with freshwater after each trip and the mounting screws are greased.

 

Its pretty lightweight at 21lb and matched with a leisure battery which should see at least 6miles (possibly much more I'm being conservative)the whole set up will be about 50lb.

 

With myself and gear I should still be within the max weight limits of my Caper (I will stuff the inside of the yak with noodles for extra buoyancy). I'll also do buoyancy tests to see if she's sea worthy.

 

Anyway I will let everyone know how I get on with it. Can always sell it if it doesn't work out. Electric trolling motors wont be for everyone but they could be for me.

 

(Some good links I found on trolling motors for yaks are:

QuietMans Yak

RiverSmallies Forum - Watercraft

 

Making a google 'Groups' search on selected motors gave me some decent info too.)

 

[ 22. May 2005, 10:44 PM: Message edited by: Speciman ]

[Simon Everett]

Specimen,

Just done a story on electric motors - general boating. It is interesting that you can increase the range of an electric motor very simply - by keeping the power drain down.

Roughly, if you can get, for arguements sake, 6 knots at full thrust - bu reducing the power setting to 75% of full you would probably still make 5 knots, but increase you range by 25% - if you were happy to toodle along at 3.5knots at 50% thrust you DOUBLE your range.

At sea, you will get much higher drain than on inland waters because of plugging wind and tide - also wave action reduces speed and increases power drain - basically you are travelling further. Think about using the motor as assistance and still paddling a bit to help it.

Initial start up takes the most drain - think about a horse drawn barge - getting it going takes the oor old horse a good heave, but then is can just plod along with the tow rope hanging in a great arc. Once moving it requires very little effort to keep a boat moving - unless against wind and tide.

Simon.

PS - put the Prowler throught he mill on Friday. It was blowing and the waves in Poole harbour were horribly short - half a Prowler length, and about 2 feet high generally out off Salterns. Came back in after a couple of hours hard paddling against a force 6-7 gusting 8 wind! If I stopped paddling long enough tocast and retrieve I was back over the line! Rate of drift was incredible and getting back out agian hard work. So Ikept her going and trolled, but there was too much weed stirred up, kept getting clogged up, so just paddled in the waves for fun in the end. Goy some great shots done from a boat. Will post some when I get time.

Towed an upturned trimaran (30 footer) in on Saturday. It was blowing a hooley. (NO You Dopes - I didn't tow it with the kayak - 400hp of Caterpillar diesel in an Ocean Dynamics RIB)

[SpeciMan]

Hi Simon. Good comments - they correspond with what I've been told elsewhere: to run it on a lower setting to increase range. However, I didn't know about the initial startup effect; I will paddle a bit first to get up to speed before switching on.

 

I'm wondering if there's the remotest chance I could tow Zzippy Caper too (if it came to it)! Only one way to find out

 

When doing the writeup on electric motors did you cover the different types of battery at all? I need a deep cycle battery which will be sealed (dont want acid leaking out) -- from what I've seen so far there's two main types Gel and AGM type batteries.

 

-- shame about the Poole Harbour fishing. There's been a strong wind down here for almost a week. Rockley is not too bad in these winds but that was quite a bit further up from where you launched. I won't go out in more than 10mph winds: force 6-7 must have been very hard work!!!

 

[ 23. May 2005, 12:24 AM: Message edited by: Speciman ]

[Simon Everett]

Wait till you see the pics!

[Simon Everett]

sorry, forgot to mention batteries. The boats I was dealing with all had fixed banks of batteries - replacing 40hp petrol engines with 4 - 5 kw electric ones, so needing about 600 - 800 amp hours of battery capacity!(You'de sink.)

 

You want to get one of the sealed gel battries. But, it won't be light if you are to have any kind of endurance range at all. Think about where you will install it - NOT IN THE CARGO WELL! It needs to go in the hull, low down. Bear in mind too, that salt water and battery acid creates chlorine gas - don't beathe it in, it will kill you. A sealed gel battery from Exide is about the best, they do a range of circular celled batteries which can be mounted at any angle - ANY angle, even upside down. They are purpose designed deep cycle too - important for battery longevity. A starting battery doesn't recover well from more than 50% drain, a deep cycle battery is designed so it will recover well from being flattened and recharged.

I would suggest you rig up some kind of harness to hold it in place (or a couple of smaller ones wired in series is better - load distribution and spot loading of the hull is reduced)within the hull itself - where it stays dry - even put them in a poly bag to keep the water off and cover the terminals in vaseline.

Simon.

[Newt]

Additional items for consideration:

 

- DC current is sensitive to wire length and wire diameter. The smaller the wire and further from battery to motor and the more power will be lost without ever getting to the battery. Totally different behavior than AC current.

 

- You did well with the Minn Kota. They tend to get the most run time for a given amount of battery than any of the others.

 

- With a Yak I wonder if you could benefit from the same dodge the float tube folks over here have found. Mount the battery in a small float tube and tow it rather than having any sort of fixed mount inside the boat.

 

Simon is right on with his recommendation for sealed gel.

[SpeciMan]

Thanks guys.

 

Given that gas can be output from the battery I guess I'll have to put some ventilation holes into its container (but if its sealed will I still hav to?).

 

I like the idea of using a couple of smaller batteries wired in series. Means I could distribute the weight more evenly and use only one battery if say I have a fishfinder and don't want to use the motor.

 

I guess having a 12volt battery onboard would mean I could hookup a marine grade airhorn too.

 

I'll have to work out the right gauge wire to use. Minn Kota detail this on their site here:

 

http://www.minnkotamotors.com/support/faq.asp#wg

 

I've heard that the propeller fitted to the Minn Kotas is geared towards quicker acceleration rather than top speed.

 

Have read positive feedback on an alternative propeller you can fit which gives a bit more power: http://www.kipawapropellers.com/ - could also try this if I find one cheap.

 

I'm surprised at how the Capers hull swallows up the noodle buoyancy floats £££. You could fit alot in there along its sides.

 

Would inflated airbags give the same degree of buoyancy given the same volume filled?

 

[ 23. May 2005, 12:56 PM: Message edited by: Speciman ]

[Simon Everett]

Part of the buoyancy you gain with any kind of filling is not necessarily from the actual degree of lift provided, but from the volume of water it keeps out! An old car inner tube works well - I had a tractor trailer inner tube as my reserve buoyancy in the bow of the raceboat - blown up until it looked lke it would burst, about 40 psi in it, but the thick rubber was under no strain - no flexing over ruts and rocks, just sitting there. Those air sacs you get for packing are a good bet for buoyancy within the hull - there is no pressure much when the hull is full, but with something in there the pressure is even less, because the water can't get into a space that is already filled - if you see what I mean :confused: They are quite strong enough for stuffing down the hatch. I have to jump on them to get them burst - but then my racing snake frame......

[SpeciMan]

For reference:

 

If you have a 12volt motor & you're using multiple batteries to aid weight distribution hook them up in parallel not series (connecting the batteries in series increases the voltage & could harm your motor if it cannae take it).

 

Some trolling motors require 24volts & hooking up 2 x 12 volt batteries in series would be appropriate.

 

Useful guide:

Wiring Multiple Batteries

 

[ 25. May 2005, 05:46 PM: Message edited by: Speciman ]

[Simon Everett]

It was a long time ago that I did my physics - got my parrallels mixed up with my series - sorry!

One doubles the capacity, the other doubles the voltage!

My mistake - perhaps that is why I only got a C!!