thrust

[capras801]

What is the min. trolling motor thrust to safely move a CP 16 on a fresh water lake (short distance, docking only)?

[capt_nemo]

capras801,

As an experiment, I once attached an old 37 lb thrust trolling motor to my 1500 lb Sun Cat. Rigged a temporary 2X4 mount on the swim ladder since I had a small borrowed outboard on the outboard bracket.

In short, it did move the boat, albeit quite slowly through relatively flat salt water in Charlotte Harbor, Florida. However, all things considered, I decided to get a 4 HP Yamaha Outboard based on my intended use for the boat.

For fresh water lake short distance use and docking, one of Motorguide's relatively inexpensive NEW R3 Freshwater Series (transom mount) should do nicely. They range from 30 lb thrust to 40, 45, and 55. Check their website out. FREE SHIPPING!

capt_nemo

[skip1930]

Well 180,000 btu per gallon of gas.

There is 12,300 something btu per hp.

And 3,412 btu per kW.

So a 4 hp gas motor uses X ? btu.
So an electric with the same X? btu needs to be Y? kW.

And four blade props are most efficient, but two blade is what we see on these things.
I'm guessing that electrics don't have enough poop to drive a four blade.

Most things electric/battery power ain't worth a thing. But that's just me and Chevy Volts.
Lets make a 100 ton electric airliner that can fly coast to coast non stop on one charge...then I'll be a believer.

I don't have time to figure it out...gotta go the work. The County calls.

skip.

[CaptRon28]

I put a 55 pound thrust MinnKota on my diesel powered Horizon last year. There's no real current on a 1,000 acre lake/reservoir near my house so the motor works very well in this environment. I can get it up to around 2.75 knots forward, maybe 2.25 in reverse. Not sure if I'd want to use this on a river or tidal water or on a very windy day. The motor has a 36 inch shaft. There are some photo's posted in the Horizon section.  MInnKota suggested that I get something in the 75+ pound of thrust range, but that would have been overkill for my needs.

I'd think that 40 or 45 pounds of thrust could probably handle the much lighter 16, but not where there is any significant current or wind.

You've got to think about batteries to handle this load. Mine aleady had 2 deep cycle case size 27 batteries. It was an option with the diesel motor. I can   probably get 2+ hours out of them at medium throttle.

[JTMeissner]

capras, I use a 40-lb thrust motor and find it quite adequate.  Use it plenty when the wind dies down on the reservoir and have a mile or so to get back to the dock.  Not fast in any sense, but capable.  Battery becomes the limiting factor, but I've never run out of power over a long weekend of sailing.

[MKBLK]

Capras -

I've been using a 28 lb. thrust Minn Kota on lakes, rivers and bays with no problem for "short" distances. On the bay (Barnegat in NJ) I did have some moments of concern with a stiff breeze blowing (the wrong way!). I've decided to "upgrade" to 36 lbs. because of pretty steep river currents (~ 4-6 mph). Bear in mind that even with a very powerful motor, the hull speed is still about 7 mph, maximum! Also, remember that the more powerful the motor, the quicker the battery will drain. Try not to operate at full power, half way (3) is plenty. If on a river, trying to fight the current, get as close to shore as is reasonable to take advantage of the quiet water. I'd say that on flat water you should have no trouble even with a small motor. My experience has shown that the 28 pounder shoved Pegasus along quite smartly. You'll see just how quickly when you are rapidly approaching the dock! I don't yet know how long the battery will last, but should be good for a couple of miles, at least.

Good luck,

Marty K.

[Salty19]

Never used a trolling motor, but the consensus seems to be about 40lbs.
Might want to go bigger to be safe for headwinds??

Take a look at Odyssey batteries. They are quite capable.  Disclaimer: Never used them for electric motors so ask them about it.
Are you trailering her to recharge?

I would love to put install an inboard electric Another day another dollar.