I realize that my canoe does not count as a foiling craft, yet. I am trying to find any help on finding the correct~ish size propeller for my 65161 motor and google keeps leading me back to foil.zone as it seems you have the most people skilled in properly sizing motor to prop combinations.
Specs:
Motor: Flipsky Electric Outboard Motor 65161 6000W 120Kv
Old ESC: Flipsky 75200 Pro V2.0
New ESC: VESC 6 75
Craft: Montgomery Wards Seaking 18ft canoe
Power source: 12X Ryobi 18V+ battery pack running in a 3S configuration (15s8p if you are counting the 18650 cells)
Propeller - Stock: Unknow size, small.
Propeller - Amazon: Propeller 3x7 1/2x8 for Yamaha Outboard
I spend 90% of my time trolling/fishing in the 5%~10% throttle range. But I like to push 80% throttle when heading back to the dock. Anything beyond 80% and the whole canoe start to feel like its going to throw itâs self apart (about 8mph). What size prop would you advise?
Interesting use of those Ryobi packs!
Iâm hardly an expert at sizing props to motors, but the 65161 is very popular for efoils. One of the props that is often used is the Fliteboard propeller (their basic cheap one, not one of the fancy ones). Itâs only about $40USD. It does require drilling out the shaft hole from 11mm to 12mm, but since itâs plastic this is easy to do.
In the USA you can find it at electricsurf.com or try ebay or look up some other Fliteboard affiliate.
I agree with S-roger the flite prop is great for efoiling. However efoil speeds are much higher. I think a lower pitch prop would have more grunt for the slow speed of a canoe. But its cheap enough to try anyway. The white prop that flipsky sells is pitch of 5 and might work well cut down a bit.
Increased top speed isnât likely as the canoe wonât go faster no matter how much force is applied. The top speed you get now isnât particularly safe based on your comment and to faster would only increase the chance of accident.
The end goal is nothing more than a better efficiency curve. The stock prop just cavitates. My Canoe is too heavy for such a small prop. The larger prop off amazon seems to be an ok fit. I know there is some math and logic to correctly sizing a propeller for a specific application. I would like to better understand that and maybe even design my own prop. My 3D printer is looking for a challenge. I am also ok with the slightly less exciting path of just buying a few different props and testing them.
An Increased top speed is always nice, but as Foilguy pointed out not very practical or safe. But it might be a good test of my safety gear when my canoe rips itâs self apart at 10mph.
plug the details into one of these propeller calculators and youâll get a sense for how fast the propeller is trying to propel you, and size accordingly.
At full speed by my rough estimate 16S, 120kv, 7.5x8 prop, you are trying to push the boat at 30-35mph with the 8 pitch which is why it isnât happy.
In any case, that boat will not go faster than the hull speed, so youâre probably going to achieve very little with all of this.
Thatâs the one. Though as windego pointed out it may not be the best for your canoe application. It makes a lot of thrust and was specifically designed for efoil, it might have too much sudden low end âpunchâ as it spins up making low duty cycle fishing/trolling unpleasant. There are some two blade props for the 65161 that might be a little better (though they are still meant for efoil).
@ mterea, that looks like a calculator for air craft. Would the density of water make a difference?
I bought the Fliteboard prop from eBay. Not too expensive. At the end of the day the best way to test a prop is on the back of my Canoe.
I think the best option is for me to design my own. My designs wonât be all that good but they will most likely be a better fit than a prop meant for an efoil. Now I just need to amass the correct tools and calculators to make a kinda informed guess at what I should design. It would also be nice to go down the toroidal prop path. Much quieter in the water (Need to sneak up on those fish), but I know thatâs a bit more crazy.
@ windego Not yet. Let me figure out some good ball park numbers then I would be happy for you to cook up something in STEP format.
It will make a difference, but not in this context I donât think.
The explanation of how it works is quite interesting, and I think likely appropriate.
The RCTestFlight competition was really cool. Watched those video s a few months back. Yes, that is a great selection of props to choose from.
Lets start applying some math to all of this an see if we can make a slightly informed guess as to what type of prop I need.
Waterline length = 15.5ft
Beam at the Waterline = 38in (3.2ft)
Enter hull draft = 6in (0.5ft)
Enter vessel weight = 480lb (80 for the raw Canoe + 400 for equipment and 2 passengers)
rated horsepower of the 65161, 6000W, peak = 8hp
Kv120 to RPM @ 54v = 6480RPM
Constant? 150? total guess.
Hull speed = 1.34 Ă â(LWL in feet) = â15.5 â 3.94 â 1.34 Ă 3.94 â 5.3 knots or about 6mph. This would explain why things feel really bad when I go above 6mph. Canoeâs can NOT plane.
Using the calculator over at vicprop.com it suggests something around a 3-blade 5x5 prop (4.9in x 4.8 pitch).
Taking stock of the props I have in hand: Stock prop, 4.75" pitch unknow
Amazon prop, 7.5in x 8pitch (Clearly a bad choice)
Fliteboard 307-A, Unknown
3D Model from Windego, pitch 5in diameter 5in
Can anyone help fill in the above missing prop data?
Although this might be an interesting thought exercise I remain unsure on what your goal is.
Canoe is a non-planing hull so is subject to displacement hull speed. This you know.
Applying more âforceâ to exceed hull speed is fruitless as you know as you just end up stern down trying to climb over your bow wave and chewing through your battery capacity for no real gain. Choice of prop to exceed hull speed I donât think makes a difference.
If you want to minimize the time it takes to go from idling to hull speed choice of prop would make a difference.
If you want to maximize battery life at a variety of speeds perhaps one prop is better than another but only your experience trying different props will tell you that. Throwing in wind and water conditions can easily skew the results though.
Now taking up efoiling as an additional hobby will provide great joy!!
@Foilguy, just trying to be more efficient. @Windego, Thanks again, I will get it printed.
This thread has been really helpful thus far. The hull speed was unknow when I started this. Now I know its pointless to try and exceed 5~6 knots. My real world testing has also confirmed this. The prop I am currently running 7.5x8 is a bad choice. My goal is still to try an find a better efficiency curve. I am not trying to find the perfect prop (I cant account for all those variables). Only one that is closer to the speed range I could realistically expect with my Canoe.
