trolling motor thrust decision

[vinnie1234]

Hi guys. I have a '78 crestliner crusader 775 open bow, fiberglass hull, 17'7 feet, 8 foot beam. Weighs about 3000lbs ready to go. I want to get a trolling motor obviously for fishing, but it would always make a nice backup in case I have an engine problem. I realize that range is limited. I won't be venturing far from shore. Here is my question: how do I figure out how many lbs of thrust for my size of boat? 55, 70, 100? New at this, don't want to make an impulse buy. What do you guys use and what are you floating in?

 

[Pony]

Most trolling motor companies will have a chart on their website that gives you idea of what they recommend for a spec length boat.

My boat is 17'6" with a 94" beam. Weighs less than yours by a little. Both my trolling motors are 80lb thrust. At most that gets me 3-4 mph at full power.....which is fine if I am trolling cranks.....and VERY fine for trolling and casting shore or docks.

I would hate to have to try and get back to shore with either of them (engine mount or bow mount)....especially if I have been using them on the trip. 80lb thrust eats a lot of battery

 

[vinnie1234]

Thanks for the tip. Very shortly after making this post I went to the minn-kota website and they actually suggest a 55lbs minimum. I had picked out an 80lb on ebay, but don't want to spend the money on that as they are significantly more expensive. I also don't want to waste my money either. Thanks!

 

[Barnacle_Bill]

Get the 80. You will regret getting a 55 for that boat.

 

[Pony]

Get the 80. You will regret getting a 55 for that boat.

Agree 100%.

 

[vinnie1234]

I just found a 4hp Johnson seahorse for $300 with a parts motor. Do you guys think this would be a better choice for my needs?

 

[woodi2014]

hi guys I just got a 2008 1675 lund explorer ss it is 17ft. and weighs 1140lbs the beam is 90'', it doesn't have a trolling motor on it was wondering if any one could recommend what thrust I should get and what shaft length.

 

[Pony]

I just found a 4hp Johnson seahorse for $300 with a parts motor. Do you guys think this would be a better choice for my needs?

What kind of trolling are you doing? If you are trying to do 2-3mph it will be a better choice than electric. I troll cranks and harnesses....so sometimes I am .7 to 1.0 mph, others I am 1.5 to 2.2 mph

 

[vinnie1234]

to be honest I don't even know. I have only ever fished from shore, not too successfully I might add. I am learning that, as well as boating. The boat is a deep v hull, so I don't expect that I will frequent overly shallow waters, and at some point I see a downrigger in my future. I know that most of the guys around here troll large spoons around 70 feet ish, usually after salmon. I would expect that with the deeper water, the engine noise wouldn't be an issue, and that I would probably want the faster trolling speed?

Since I am clearly NOT a fisherman yet, the main motivator for the additional motor is as a backup in case there is trouble with the main engine while I am out and about. I would never venture more than a couple km's from the shore, so it should be a short jaunt to safety in the event of any issues.

I am quite capable of making use of the spare engine, so it seems like a decent deal for me. The price is right too. Once I have it, and learn how to bring home dinner, I am sure that an electric bow mount unit will also be in the cards, but first things first. That may be a while yet, as I know comes the winter I have to rip the boat apart and redo the stringers and floor.

 

[UncleWillie]

I am also NOT a fisherman. But I am a diver.
I have noticed that fish completely ignore sounds from motors.
Motors sound high pitched underwater. The propeller is the noisemaker, not the engine/exhaust.
Fish respond to sub audible pressure waves like that produced from moving arms and the tails of swimming predators.
Talking can not be heard. Foot steps on the hull would be a threat sound.
They also are wary of anything moving Quickly above them that may resemble a predatory bird.

A slow moving boat or a diver at or below their level is a non-threat object in their world.
The small gas engine should not be a fishing issue. You do not fish UNDER a trolling boat in any event.

The plus side is that a 100 amp hour battery will yield about the same amount of energy as one Pint of gas.
To put it another way; One gallon of gas will move the boat about the same distance as 8 batteries and weigh 100 times less.

 

[vinnie1234]

Thanks uncle willie. That was part of the reason I started to look towards gas. Also, good observations about the fish. I think that; all things considered this would work for me. Now I have to go and look at this thing and make sure that it works.
Cheers,

 

[vinnie1234]

Well, i went to see the motor tonight. It's in good shape. I cam home with a 1970 and a 1975 model year 4hp, plus a complete trim tab setup with controls, plus a cylinder head for my 3.0L Omc, plus a spare intake manifold and 2 freshly rebuilt carbs - and a kicker plate for the outboard. Gotta love good people. All for $250! Turns out the seller is a neighbor and wanted to get rid of all this stuff. He is a good guy too, and I'm not just saying that because of the wicked good deal.

 

[Pony]

Well, i went to see the motor tonight. It's in good shape. I cam home with a 1970 and a 1975 model year 4hp, plus a complete trim tab setup with controls, plus a cylinder head for my 3.0L Omc, plus a spare intake manifold and 2 freshly rebuilt carbs - and a kicker plate for the outboard. Gotta love good people. All for $250! Turns out the seller is a neighbor and wanted to get rid of all this stuff. He is a good guy too, and I'm not just saying that because of the wicked good deal.

Sounds like a great deal! Good choice on the kicker. Trolling Salmon you will NEED downriggers and you will be trolling at a decent speed. I have downrigger plates on my boat, but we haven't ventured out to Lake Michigan to troll Salmon yet. We troll walleyes on Winnebago and Green Bay.

If I had the means to get another small motor, I would mount a kicker....and just might at some point. I have 4 deep cycles powering my electric. It gets me fast enough, and it trolls a decent amount of time. If I was only trolling harnesses and was trolling slower, I could drop down two batteries.

 

[vinnie1234]

You guys were right about the electric motor I think. The 4 horse gets me around 2.5 mph. As for trolling, I have no downriggers yet, but just picked up a rod with line counter and dipsy divers.... Gonna give that a whirl.