Thread: How much motor do I need?????

I got a 40# Minkota on a 14' Northwoods Super Fish and I have a 3 Cyl. 25 Johnson hanging on the back, my girlfriend and I, and all our fishing gear in the boat. And I can troll till the cows come home. How fast do you troll? You got a 70# on the front and getting an 80# for the transom? Sounds like a lot of power to me, along with batteries. That's probably a 24 volt system? Do you have a gas motor?

No gas motor. This one, at least for the immediate future, is going to be purely electric-only. At some point I'll get a small tiller controled gas motor for use on some of the larger Corp of Engineers/Georgia Power lakes, but most of the lakes in my immediate vicinity (100 to 850 acre lakes) are electric-only ---- you can't even have a gas motor anywhere on your boat, much less actually use one! I know I'm fine with the 24 volt 70 Lb motor on the bow, but I'm concerned with whether or not a 24 volt 80 Lb motor will have enough push to adequately propel a boat this size (I have no idea what she weighs, but she's 17.5' long with a 78" beam and will have most of the usual "bass" boat compartments, livewells, etc but NO fuel tank, gas motor, or steering mechanism/console. She WILL have at least 2 trolling motors and I'm figuring on 2 type-29 batteries per motor, plus 2 more for running lights, livewell aerator, bilge pump, fish finders, etc so figure on 6 batteries on board.)

Luckily for me, I work for a major deep-cycle battery manufacturer (Trojan), so the cost of batteries is a non-issue for me! (I knew eventually SOMETHING good would come out of this job!)

They make a great 6volt. I've got 4 in my 5th. wheel for power. I wish I could get 4 new one's, the one's I have are 7+ years old. Trojan 105's Can't beat them. I would think that 80#er should push you along pretty good.

I would try it with the 70# on front first to see how the thrust of it does then decide if you need more or if it is enough.

Originally Posted by Gunslinger

Quick question for ya'll.

I just bought a 1984 Alumacraft 17.5' flat-bottom bass boat. Tore out the console, cables and removed the Johnson VRO 70 from the back (Which I promptly sold for a little over 1/2 of what I paid to start with!). I am re-decking her (I already re-plumbed and got both livewells working properly) and converting to an electric-only set-up since there are many electric-only lakes in my area. I already have a Minn Kota Edge 70 (24V) to go on the bow. I am going to put (at least one) a tiller-style trolling motor on the transom. I am currently leaning towards a Minn Kota TRAXXIS 80. Do ya'll think that will be enough motor to drive this boat at a decent trolling rate, or should I spring the extra $150 and get a Minn Kota RipTide 101-Lb thrust saltwater motor?
I'm not wanting to pull skiers or anything like that, but I also don't want it to go 2 mph when I'm trying to get up the lake to my best fishing spots! If I can get 6-8 mph out of her that would be wonderful (I would like faster of course, but the law of diminishing returns kicks in at some point!). I plan to use the transom motor purely "to get there" or for trolling, then use the 70-Lb front motor to manuever around while fishing.

I'm just trying to determine if the 80Lb motor will be sufficient. Any and all input is GREATLY appreciated!!

You can get some rough performance numbers if you know the weight, length at waterline (about 16'), and power from here Boat Speed | Hull Speed | Speed Calculator

My guess is there will be little difference in speed between 80# and 101# of thrust and your top speed will be around 4 mph.

I believe the 101 lb is a 36 volt system. that means another battery . Take that into consideration.

Originally Posted by PanMan_VA

You can get some rough performance numbers if you know the weight, length at waterline (about 16'), and power from here Boat Speed | Hull Speed | Speed Calculator

My guess is there will be little difference in speed between 80# and 101# of thrust and your top speed will be around 4 mph.

That's sort of what I've been thinking. I just don't see a 101 pushing that much more than the 80 --- but I'm no expert. I'm leaning towards just getting the TRAXXIS 80, and if that just won't cut it, add another 80 beside it with a tiller set-up so they operate in tandem (which wouldn't be that difficult to design/build).

What about a Torqeedo, 3 HP output $1,900 at Cabelas