Trolling Motor Selection - Volts, Thrust, and Shaft length

[Tin Man]

Preparing to purchase a new TM. Going with Minn Kota Terrova (no transducer...only remote and iPilot)

Spoke to MK today. Here are MK answers to my questions about thrust, volts, and shaft length....

Thrust - MK: 2# for every 100# of boat weight (including motor, gear, passengers, etc). My 2023 Tracker Pro Guide V16 SC weighs about 1200#, plus gear people = 2000#
That would equal 40# of thrust. That seems VERY low!! Maybe that's why my boat came equipped with a 42# thrust, 12V, 54" shaft TM!!!

Volts - MK: If you use a 24V TM with 80# of thrust on my boat, I may experience difficulty in boat staying anchored using iPilot....as boat would be too light for the amount of thrust. It was a technical explanation, but it made believe that you can "overthrust" in the selection of a TM. I see most people with a similar sized and weight boat opt for the 24V 80# thrust when upgrading. MK claimed it can be too much thrust considering the formula they use for thrust selection. I mentioned that perhaps people select the 24V for longer run times...MK stated you can run 2 12V batts in parallel for added run time.


Shaft Length: - My boat came equipped with a 54" MK Powerdrive. Basic model with only a foot pedal. No iPilot. It should be correct length. MK: Add 20" to distance from bow mounting location to waterline. Since my new boat has not been used, I have no waterline!

Questions....Anyone with the same or very similar boat and specs of mine (weight, gear, deep V hull, etc):

TM size?
Shaft Length?
Thrust?

Did you select 12V or 24V and why?
Thrust amount and Why?

I am most intrigued by the thrust and 12V VS 24V discussion.

Thoughts?

Thanks!

 

[flatheadsteve]

Overthrust? Hogwash! A 24v 70-80lb is about perfect on that size boat. Especially when dealing with wind, tides, and currents. I really can't understand their reasoning for that it's not like when the motor goes to adjust position while on anchor it uses 100% throttle. 24v motors dominate on the rivers out here even on smaller boats than yours. I run a 36v it's probably way more thrust than I've ever need it will move my 20ft boat just shy of 5mph and the anchor lock works perfectly.
Edit to add I went 36v because I got the garmin to sync with my GPS/fish finder. It can be used as a 24volt but I figured why spend the money then not utilize it's full capabilities.

 

[MrGiggles]

What they say regarding the motor being oversized is true, but only in terms of spot lock performance. They are roughly calibrated to ramp up speed in accordance with boat size, if the motor is undersized, the boat may drift off the waypoint before the motor is ramped up fully and brought back, if oversized, it may ramp up too quickly and overshoot. The higher end Minn kotas have a setting for this (called boat scale as I recall), however it is not available on the Terrova if I remember correctly.

24V motors are quite a bit more efficient, resistance losses are halved. Even with two identical batteries, the 24V will go further than the 12V. If you do any electric trolling, fish in heavy current, or on big wind-swept lakes, 24V is the way to go. If you're only fishing small bodies of water, trolling with the outboard, or anchoring a lot, a 12V motor will do just fine. I have had both on my boat, I prefer the 24V as I do a lot of crankbait/bottom bouncer trolling, I used a 40lb thrust Powerdrive for quite a while and found it to be more than adequate, it was just a little bit hard on batteries while trolling crankbaits, and I wanted Ipilot so I upgraded to the 24V Terrova.

 

[FuzzyGrub]

FWIW: I calculated our normal running weight as 2000lb on our G3/90/65. That included us, batteries, fuel, trolling motor, everything. The dealer recommended a 70lb thrust 24V MK system, and boat was configured for a 24V system from factory. We decided to rig ourselves, and went with MG 70lb Xi3. It has worked great for us on the river. We use anchor lock allot. Most of the time in varring currents but also in flat water sections. Never seen it over shoot. It is constantly adjusting speed though. Don't know if it is because it is better matched to boat or MG uses a different algorithm.

One thing we quickly learned was not to engage the anchor lock too early.. ie wait for the boats momentum to nearly stop. If you don't, it will quickly go to full thrust to get back to the spot. Can catch you off guard and cause you to stumble as boat quickly goes in the reverse direction.

How well did you think the 42lb trolling motor performed? I would be skeptical of going that low, even if thought it worked well. A 55lb would be minor upgrade, but might be sufficient. I have 45lb MG wireless on the 1648, but that is a much lighter boat than the G3. If you are at or near 2000lb, I'd go 24V 70/80lb thrust.

 

[Buster]

I have a 14' Lund from 1966. Recently put a 12v Terrova on it with iPilotLink. There is no question even the 12v overpowers the boat. At certain speeds, when tracking on a heading or following contours, the motor hits an oscillating feedback loop and overadjusts more and more. SpotLock will frequently wrap the motor around multiple times.
Fully loaded with 3 people it's less of an issue but when I'm fishing alone it's a real problem. When alone the gross weight is barely 500 pounds, so take that into consideration. It's just one person's experience with an outlier setup.

 

[lightflyer1]

Modern problems! My MK tiller control, variable speed has no issues. Really didn't need something that costs more than the boat it is on. I am going for simplicity and reliability this time around.

 

[jethro]

I never heard that about overpowering the boat but I suppose I believe it. I went 36v and 112# thrust for the added runtime but my boat is big and heavy. I'm not super electrical savvy but as I understood the 36v will give you extended run times even when using the equivalent amp hours for a 24v system. I'm using mine as autopilot in conjunction with my gas kicker motor when trolling for salmon and spot lock when I'm fishing the salt. My gut instinct is telling me that a 54", 24v 80lb trolling motor would be perfect for your boat but I can understand your trepidation after talking to Minn Kota. I know I would buy that setup in a heartbeat.

 

[FuzzyGrub]

I have a 14' Lund from 1966. Recently put a 12v Terrova on it with iPilotLink. There is no question even the 12v overpowers the boat. At certain speeds, when tracking on a heading or following contours, the motor hits an oscillating feedback loop and overadjusts more and more. SpotLock will frequently wrap the motor around multiple times.
Fully loaded with 3 people it's less of an issue but when I'm fishing alone it's a real problem. When alone the gross weight is barely 500 pounds, so take that into consideration. It's just one person's experience with an outlier setup.

Well, I guess that confirms what MK told him. Seems odd comparing to my MG. The Xi3 will rotate back 360 instead of wrapping the cord. Its hard to imagine, if you had this issue, and you called MK customer service, and they tell you its your fault, you bought too much thrust!

 

[Still Afloat]

I’ll add a vote of BS as well. A Terrova 24V/80 moves my Crestliner 1750 around with authority. I’ve never wished that I had less thrust. Heck, I’m even planning to use an 80 on the little 1448M.

It’s probably a good call to delete the transducer if you are getting the iPilot link. The coiled cord coming off the head will tolerate one extra cable routed inside of the coil but, it tends to bind up with two cables inside of the coil. It’s a MK Mickie Mouse approach for cable routing in my opinion. Also, the transducer and Ethernet cables coming off the MK are a few feet longer than necessary. This creates a bit of mess.

If I were to do it all over again I’d go with Lowrance and Powerguide. The menu is more intuitive and there are useful features for TM control like zigzag and lazy-S. Unfortunately, now that I have two Terrovas and a bucket full of Humminbirds I’m stuck. It’s like cordless power tools, once you get a pile of Dewalt batteries, for example, it’s expensive to shift to a different brand.

If you are not already heavily invested in HB and MK then shop around. Learn what the competition has to offer.

 

[thill]

On my 16' tin boats, I've recently run a 55# thrust and a 70# thrust. To be honest, there wasn't a lot of difference. The 70 probably had a little higher top speed, but it wasn't particularly noticeable, and I didn't check the GPS.

I'm currently running 55# Terrovas on both my 16' Princecraft SC and my, 16' Spectrum dual console. They run great, even in heavy currents. I use (2) 100AH TimeUSB lithium batteries, and they last forever. Very happy with the setup

THAT BEING SAID... If I were buying a new motor, I would probably pick a 24V motor, if the costs were close to the same, especially if you are in a very windy area with running tides or river currents and so on. Resale value will be better, and you can keep it if you ever upgrade to a bigger boat.

 

[80monark]

Preparing to purchase a new TM. Going with Minn Kota Terrova (no transducer...only remote and iPilot)

Spoke to MK today. Here are MK answers to my questions about thrust, volts, and shaft length....

Thrust - MK: 2# for every 100# of boat weight (including motor, gear, passengers, etc). My 2023 Tracker Pro Guide V16 SC weighs about 1200#, plus gear people = 2000#
That would equal 40# of thrust. That seems VERY low!! Maybe that's why my boat came equipped with a 42# thrust, 12V, 54" shaft TM!!!

Volts - MK: If you use a 24V TM with 80# of thrust on my boat, I may experience difficulty in boat staying anchored using iPilot....as boat would be too light for the amount of thrust. It was a technical explanation, but it made believe that you can "overthrust" in the selection of a TM. I see most people with a similar sized and weight boat opt for the 24V 80# thrust when upgrading. MK claimed it can be too much thrust considering the formula they use for thrust selection. I mentioned that perhaps people select the 24V for longer run times...MK stated you can run 2 12V batts in parallel for added run time.


Shaft Length: - My boat came equipped with a 54" MK Powerdrive. Basic model with only a foot pedal. No iPilot. It should be correct length. MK: Add 20" to distance from bow mounting location to waterline. Since my new boat has not been used, I have no waterline!

Questions....Anyone with the same or very similar boat and specs of mine (weight, gear, deep V hull, etc):

TM size?
Shaft Length?
Thrust?

Did you select 12V or 24V and why?
Thrust amount and Why?

I am most intrigued by the thrust and 12V VS 24V discussion.

Thoughts?

Thanks!

I upgraded my monark 1644f bass boat with a minn kota terrova 24v 80lb 45 shaft us2 w/i-pilot+blue tooth. Yes it has boat scale. Boat originally came with byrd double eagle 12/24v 33lb . Boat with outboard, TM, batteries, accessories with two fisherman roughly 1100lbs . Iam extremely pleased with the spot lock and high thrust in windy conditions. As others have said, slow boat down before engaging spot lock to avoid a sudden jerk.

 

[airshot]

All depends on how you use this motor. Heavy currents ? Heavy winds ? Just small moves looking for fish or serious trolling on big water ? I have a 16' Sylvan V btm side console about the same weight as yours. I have a 12v 55# thrust 54" shaft MK bow mount with spot lock. Works very well....I troll in Lake Erie for walleye, I have two 12v batteries together for longer trolling time.. I can run for almost 8 hrs if batteries are full to start. Would I want less power...no way, do I need more power ? Probably not, but definetaly not less !! For deep water trolling the 55# is adequate, for shallow water bass/ crappie it is more than enough !! I also use a little 2.2 hp gas kicker motor, it is locked in straight forward position and I use my remote controlled MK for steering. This uses less battery power, fights wind better, steering from the bow is better and that little motor runs all day on a gallon of gas. Being small (30 lbs) it runs at about half throttle or a little more so vibration is very minimal....I can steer, fight and net my fish without leaving my seat. The spot lock works great, haven't used an anchor since I got it...even in two foot chop it holds, but any rougher would need a longer shaft. As far as power goes, it works well, would not go with less, MK's numbers are minimums...going up to 80 # would be overkill in my opinion, but...where and how will you be using it is the real answer here.

 

[Tin Man]

I’ll add a vote of BS as well. A Terrova 24V/80 moves my Crestliner 1750 around with authority. I’ve never wished that I had less thrust. Heck, I’m even planning to use an 80 on the little 1448M.

It’s probably a good call to delete the transducer if you are getting the iPilot link. The coiled cord coming off the head will tolerate one extra cable routed inside of the coil but, it tends to bind up with two cables inside of the coil. It’s a MK Mickie Mouse approach for cable routing in my opinion. Also, the transducer and Ethernet cables coming off the MK are a few feet longer than necessary. This creates a bit of mess.

If I were to do it all over again I’d go with Lowrance and Powerguide. The menu is more intuitive and there are useful features for TM control like zigzag and lazy-S. Unfortunately, now that I have two Terrovas and a bucket full of Humminbirds I’m stuck. It’s like cordless power tools, once you get a pile of Dewalt batteries, for example, it’s expensive to shift to a different brand.

If you are not already heavily invested in HB and MK then shop around. Learn what the competition has to offer.

I was keeping it MK as the mounting hole pattern is the same as the MK Powerdive my boat came with new. I'll bet that the Motorguide mounting hole pattern is different. I do not want to drill four new holes in my new boat to accommodate a different brand!! If holes were same, perhaps.

 

[MrGiggles]

The cable wrapping thing on Powerdrives and Terrovas is a major annoyance, but I'm not sure that it has as much to do with the size of the motor/boat as it does poor programming on MK's part. Sucks when you're fishing a spot, not paying much attention and the motor wraps the cables then cancels spot lock. Once you've realized what happened you're way off and get to start over.

One thing that helps is to make sure the boat stops moving completely before you hit spot lock, and approach your spot from straight downwind. I've found that it is most likely to wrap if it has to move the head more than 90*. It should be programmed to only rotate opposite of the last move, but it simply moves whatever direction is nearer to the target heading.

Once I started being more careful about when I hit spot lock, it only tends to wrap when the wind is really variable, or when it's dead calm and the boat tends to move around aimlessly. It definitely works best with a steady breeze.

What bugs me the most, is that mine is smart enough to feel the added drag from twisted cables and cancel spot lock, but it's somehow not smart enough to just not do it in the first place!

 

[Buster]

Well, I guess that confirms what MK told him. Seems odd comparing to my MG. The Xi3 will rotate back 360 instead of wrapping the cord. It's hard to imagine, if you had this issue, and you called MK customer service, and they tell you it's your fault, you bought too much thrust!

Don't get me wrong--I love the setup. This little tinny was never meant to have a bow mount and for years I used a tiller. Part of the issue is that the boat is so small that wherever I sit, the opposite end is barely in the water. (The middle seat just doesn't make sense.) when I have just one other person in to balance the boat and add some drag the problems almost completely disappear. But while I think "overpowering" a trolling motor is likely only in edge cases, I have an edge case and thought the OP would benefit from knowing what situations might cause a problem so he can determine if he shares the problem.

 

[Ray Clark]

I have a 55# thrust Powerdrive on my 14' Lund. Boat's gross weight on the water with two fishermen and gear is about 1000 pounds. I'm using a ProNav unit for spotlock and TM control.

I like the setup. Using spotlock effectively is a learned skill. I find that it's best to set the spotlock when facing the bow into the wind/breeze when nearly stopped. Otherwise, I can get some "pinwheeling" as the unit attempts to bring the boat to a stop and then return to the place where the button was pushed.

Cord wrap needs to be managed as well. However, the better I am at setting the spot lock as described above, the less cord wrap I seem to deal with.

Spotlock also seems to work better when there's a breeze to work against. It's smoother and less prone to cord wrap.

 

[Still Afloat]

I have a MK 50 on 11’ sit on top Ocean kayak. It’s a factory configuration. Also ran a MK50 stern drive on a previous 1246 Jon. The Jon could not make way in windy conditions and I never felt that yak was overpowered.

In my opinion running a MK 50 on a 16 ft or larger boat (regardless of the weight) is the equivalent of peeing into the wind.

Edit my Ocean Kayak Torque has a 45, not a 50.

 

[airshot]

Hmmm...folowing this cord wrap issue...never had it on my powerdrive 2 MK bow mount. Had it for over two years and never a wrap up. Thought about it when I first got it, but it has never wrapped more than one full turn when controlling itself. After that one full turn, the motor stops the prop and turns back a full turn before starting the prop again. I do know, that I can wrap it more when under manual control, but when on the auto control, spot lock, anchor lock or whatever it is called has never happened. Always stopped and backed up after one full turn. What am I missing, or what are others missing ??

 

[jethro]

The cable wrapping thing on Powerdrives and Terrovas is a major annoyance, but I'm not sure that it has as much to do with the size of the motor/boat as it does poor programming on MK's part. Sucks when you're fishing a spot, not paying much attention and the motor wraps the cables then cancels spot lock. Once you've realized what happened you're way off and get to start over.

I wonder if Minn Kota has fixed this since your experience? I don't have this problem at all with my Ulterra which is a late '19 build and apparently the latest build and software. I will stay on spot lock for hours on end if I find a good spot for ground fishing haddock, fluke, bluefish, sea bass etc. The cord wraps around itself a few times then all of a sudden the motor will do it's own thing to unwrap back to normal and continue on.

Don't get me wrong, I have plenty of other problems but not that particular one at all.

 

[Still Afloat]

Hmmm...folowing this cord wrap issue...never had it on my powerdrive 2 MK bow mount. Had it for over two years and never a wrap up. Thought about it when I first got it, but it has never wrapped more than one full turn when controlling itself. After that one full turn, the motor stops the prop and turns back a full turn before starting the prop again. I do know, that I can wrap it more when under manual control, but when on the auto control, spot lock, anchor lock or whatever it is called has never happened. Always stopped and backed up after one full turn. What am I missing, or what are others missing ??

I’ve had the death wrap happen on multiple occasions with two different Terrova units while under iPilot control. I always caught it before the TM shut down. For those that are seeing TM shutdowns, I’d guess that the steering servo in an overcurrent situation and the control turns it off.

At any rate, the wrapping stresses the steering servo and cables. Sooner or later something will break.