I've been upgrading my kayak over the years for more speed from my trolling motor.  

 

I started off with a 30# Minn Kota C2 mounted off to the side, behind the seat.  Max speed was about 2.9mph.  

 

Then I tuned the motor by rotating the housing slightly.  Gained about 10% and was up to 3.2mph. 
 

Next, I experimented with the depth of the motor and found it worked best with the centerline about 12" below the water.  However, I couldn't turn to the right without striking the hull, so this was no good.  
 

Later I mounted the motor on the stern and was able to get the appropriate depth and center the propulsive force and gained another 10%, going to 3.6mph.  
 

Next, I upgraded to a lithium battery which reduced my weight by 50lbs and upped the voltage slightly.  My new top speed was 3.9mph.  About another 10% increase.  
 

Lastly, I installed an RC airplane prop (APC 10x5 LH) and gained another 10%, bringing my new top speed to 4.3mph.  I had to install a 3/8x3/4x3/8 nylon washer on the back of it to get the nut to secure it.  I lost a lot of acceleration doing this, but it still only takes about 5 seconds to hit top speed.  It's also quieter and I believe slightly more efficient. 
 

All in all, I went from 2.9 to 4.3 mph using the same motor and kayak.  That's almost a 50% increase in speed!  I don't think there's much more room for improvement without switching out the motor for a torqeedo or installing a planetary gearbox transmission.  And while the speed is nice, with it came greater efficiency for longer outings and allowing me to cover more distance.  

Carry your spare prop with you when you go. That airplane prop will chip and break on about any hard thing you hit. The minn kota props are resilient and will chip or dint, but they won’t break. The RC prop will brake off large pieces or more and what’s left will be a heck of a wobble to get you back to the ramp. 

I do.  But that airplane prop is sturdier than it looks.  It's fiberglass reinforced nylon.  But the old prop just weighs a few ounces, so there's little reason not to bring it.

 

Plus, unlike in a big boat, it's no big deal to break out the paddle.  

10 hours ago, Bankc said:

I do.  But that airplane prop is sturdier than it looks.  It's fiberglass reinforced nylon.  But the old prop just weighs a few ounces, so there's little reason not to bring it.

 

Plus, unlike in a big boat, it's no big deal to break out the paddle.  

 

I have used those airplane props.  I have also broken those props, hence the warning.  The edges will be the first to start to go.  They will round over first.  You can file/sand them back to a smooth edge.  After a couple times of that you start losing material on the edge.  Any rock hits at full speed will break it.  The minn kota prop just rolls the edge and pops up the motor for me.  

 

Like you said, its easy enough to carry a spare.  At one point I carried 3 props in the kayak (one on the motor and two spare).  Since my plane prop broke, I just keep the two minn kotas.  

The speed increase is great. The loss of acceleration in a yak is not a big deal. Sounds like it worked out magnificently!

13 minutes ago, casts_by_fly said:

 

I have used those airplane props.  I have also broken those props, hence the warning.  The edges will be the first to start to go.  They will round over first.  You can file/sand them back to a smooth edge.  After a couple times of that you start losing material on the edge.  Any rock hits at full speed will break it.  The minn kota prop just rolls the edge and pops up the motor for me.  

 

Like you said, its easy enough to carry a spare.  At one point I carried 3 props in the kayak (one on the motor and two spare).  Since my plane prop broke, I just keep the two minn kotas.  

I'll might have to buy a batch of plane props.  We'll see how long they last.  But the speed and reduced noise make them worth it to me.  Plus, they're about 1/3rd the price of the Minn Kota props, which admittedly do last forever.  

45 minutes ago, Bankc said:

I'll might have to buy a batch of plane props.  We'll see how long they last.  But the speed and reduced noise make them worth it to me.  Plus, they're about 1/3rd the price of the Minn Kota props, which admittedly do last forever.  

 

yeah, that's the usual route.  next time you order airplane props, just grab a couple.  

 

For me, I've decided they aren't worth it.  Compared to the MKP2 standard prop, I pick up about 0.3-0.4 mph total.  That's nice, but I can only use it until the start of May or so before there is enough grass on the lakes to kill it.  The airplane props do NOT do well with grass.  They tangle quickly and are unusable.  The slower acceleration is also trickier with spotlock if it is gusty conditions.

50 minutes ago, casts_by_fly said:

 

yeah, that's the usual route.  next time you order airplane props, just grab a couple.  

 

For me, I've decided they aren't worth it.  Compared to the MKP2 standard prop, I pick up about 0.3-0.4 mph total.  That's nice, but I can only use it until the start of May or so before there is enough grass on the lakes to kill it.  The airplane props do NOT do well with grass.  They tangle quickly and are unusable.  The slower acceleration is also trickier with spotlock if it is gusty conditions.

Ah.  Yeah.  I don't have spot lock (but that would be nice).  And there's not much vegetation around here, since most of these lakes are man-made water reservoirs.  They spray for grass so they don't clog the drainage pipes.  And that extra 0.4mph give me about 30 more minutes of fishing time across the course of a day.  

 

There's a reason Minn Kota chose their prop geometry the way they did.  It's a good overall balance between the most common needs.  I'm just not their typical customer who's using the trolling motor for what it was originally designed for.

Just curious how does that prop do in current? 

25 minutes ago, Darnold335 said:

Just curious how does that prop do in current? 

 

same as the others, same relative performance that BankC noted above.  Compared to the stock MKP2 you'll pick up about 0.4 mph give or take regardless of standing or moving water.  I'd hesitate putting it on the rocky susky though for the reasons I noted above unless you have a backup plan.  Breaking on rocks is a real thing for this prop.

Just now, casts_by_fly said:

 

same as the others, same relative performance that BankC noted above.  Compared to the stock MKP2 you'll pick up about 0.4 mph give or take regardless of standing or moving water.  I'd hesitate putting it on the rocky susky though for the reasons I noted above unless you have a backup plan.  Breaking on rocks is a real thing for this prop.

Gotcha thank you! Every once a awhile I load up a canoe with a TM and do some creek floats.

I've heard about these airplane prop upgrades for the Minn Kota motors but never could use it where I fish, which is the Florida everglades and marshlands. I can spend a lot of time chewing up the hydrilla getting to where I need to go, so speed is not a defining factor. Besides, I don't think an airplane prop would even be up to it, probably just stall out? I like the torque, the get-up and go of the stock prop. If anything, I would want more torque. My Old Town boat already does almost 5 mph with the wind, which is plenty fast enough....with the wind lol I think the most gains that I've ever had, if any, has been through weight reduction, going light, keeping things simple, carbon fiber oar, stuff like that can make a BIG difference with propulsion as well as power usage....in my opinion. 

3 minutes ago, Zcoker said:

I've heard about these airplane prop upgrades for the Minn Kota motors but never could use it where I fish, which is the Florida everglades and marshlands. I can spend a lot of time chewing up the hydrilla getting to where I need to go, so speed is not a defining factor. Besides, I don't think an airplane prop would even be up to it, probably just stall out? I like the torque, the get-up and go of the stock prop. If anything, I would want more torque. My Old Town boat already does almost 5 mph with the wind, which is plenty fast enough....with the wind lol I think the most gains that I've ever had, if any, has been through weight reduction, going light, keeping things simple, carbon fiber oar, stuff like that can make a BIG difference with propulsion as well as power usage....in my opinion. 

if you want more torque and weed fighting, the MKP6 weedless wedge prop is the one to have.  You drop about 0.4 mph on it, but the amount of immediate thrust when you hit the button pushes away most weeds before they even thing about wrapping.  That plus the ninja blade and you're cutting through a ton of thick stuff.

18 minutes ago, casts_by_fly said:

if you want more torque and weed fighting, the MKP6 weedless wedge prop is the one to have.  You drop about 0.4 mph on it, but the amount of immediate thrust when you hit the button pushes away most weeds before they even thing about wrapping.  That plus the ninja blade and you're cutting through a ton of thick stuff.

Thanks, I'll definitely look into that! Having more torque will make a big difference. I'd give up a bit of speed any day for some extra torque.