Trolling motor vs Outboard

Here is my dilema. I have a 50lb thrust minkota bow mount trolling motor. (that is not the problem). Problem is depending on where I am on how much water is in the back channel, I just don’t have enough power in the trolling motor to move the boat up stream. I really don’t like to use the big motor while trying to limp along do to the noise and speed factors. I have been looking at getting a new 110lb thrust, but my god. They don’t give them away. I think I could probably get away with a 5ish hp outboard, and probably pay less. Any opinions/suggestions on this matter would be appreciated.

This is my personal preference here but I would go with the small gas kicker motor. You’ll be able to do the slow troll thing but also have some extra go when trolling cranks into current or spinners on the lake into the waves. Much more versatile in my opinion.

I’m not sure that adding more thrust will help. Electrics all have the same top speed. I think the motors turn at the same RPM with no load. The pitch of the prop is also the same. Therefore they all have the same top speed (once you have enough thrust for your boat).

If the top speed is somewhere around 1.5 – 2 mph and your running into current that is moving that fast or faster….

Put a 101# thrust on a canoe, and it won’t go any faster than the 50# thrust will on a 16′ boat.

WADR…I’ve never heard that one.

If this is the case wouldn’t one pound of thrust be enough if 101 equals 50.

RPM measures the internal revolutions of the crankshaft. My 225 turning 5500 revolutions per minute versus a 50 HP turning 5500 revolutions per minute is not the same. It takes HP to turn the gears in the drive train faster. Bigger pistons and cylinders with more gas and more air equal bigger explosions.

Thrust can be converted to horsepower.

Horesepower is needed to move the weight of of the boat with the resistance of the water. So the weight of the boat versus the friction of the water determines how much horsepower is needed and how fast you can go.

There is law of diminishing returns when it comes to speed. A 200 HP motor on a 16 ft canoe will not give you twice the speed of a 100 HP or 40 times a 5 HP.

Holy crap! I was thinking the exact same thing. That was deep man.

Take a look at the Minnkota props…. They are the same pitch. Then look at the rpm’s on the motors… again you will see they are the same.

Here’s the difference. The rpm ratings are with no load. When trying to push a 20 foot boat a 24# thrust motor will not be able to achieve max rpm. However once a motor achieves it’s max rpm it will not go any faster. Try it… if you have properly sized bow and stern mount trolling motors and run them both at once, you will not go any faster. (actually you will probably go slightly faster since the prop will slip a little less but you will not notice any difference)

PS: I never said a 50 = 101. Just saying that if a 50# thrust motor is the correct size for your boat, that upgrading to a 101 will not move your boat any faster. It’s rpm’s x pitch of the prop.

The key ingredient that you are missing is the resistance of the water.

Yes, the prop will turn the same amount of water if the pitch/diameter and the rpm is the same.

However, there is “slippage” with water. Meaning resistance of the boat mass of the hull through the water.

Ero, the more props, the more water you are pushing vs. the water resistance of the hull.

Treat thrust as a point of moving weight. Example is the F14 fighter. The plane weighs approximately 14000 pounds. However, it only generates 12000 pounds of thrust. This means if the plane would go straight up into the air, it would loose acceleration.

Now, the F16 fighter weighs approximately 15000. However it generates 17000 of thrust. This means the plane will accelerate going straight up into the air.

Make sense? Thust ratio to resistence ratio.

I should have mentioned then prop thing. It takes HP to twist the screw in the water.

? Are electrics direct drive or are their gears to the propeler?