One more thing. Your kayak isn’t a planing hull. It’s max speed is limited to it’s length at the waterline. https://en.wikipedia.org/wiki/Hull_speed It’s worth measuring how much throttle is required to reach full speed and never let your S/W go beyond it for cruising. It’s just a waste of energy (lower run times) as it won’t go any faster.
Steve - Thanks for the info, interesting project you have.
What is the cruising speed of your system?
Ours is planned for low speed 3-4mph. It is basically an alternative to a traditional trolling motor setup. Something a bit more clean and simple. Not for anything highspeed.
Looking good, @schoonerlabs! I’m very curious to see how fast the thrusters will push a kayak like this.
Thanks. We are as well )
I think it will really come down to testing and go from there. Either way the pontoons will still stand on their own if the thrust is lacking.
Also planning to test to fixed mounted thrusters on the rear of the kayak as another option for placement without pontoons.
Interesting project. To my eye, the strut looks over kill for the size of craft and amas. Might want to shave them down and give them a more streamlined shape. Also, looking at the kayak, it looks pretty beamy so is probably pretty stable as-is. Have you taken it out in the water? Does it need additional stability?
The foam “wings” currently is in rough form, so will be much smaller and basically just currently to form the shape for the mold for a thin fiberglass covering for looks not structure. An aluminum tube will be the support running underneath. The wing will just be a thin curved top surface ultimately, not a solid thick piece as the foam is now, probably less than an 1/8" thick with open bottom and slight dropped edge. Bulk of the foam there now is jsut for structure to hold the top shape basically.
This is meant for basically any kayak or canoe not just the one shown which is fairly wide already as you have noted.
The pontoon setup with motors is typically used for fishing kayaks, not pleasure paddling. This is meant to be an option to existing pontoon setups for fishing that use traditional trolling motors.
Sounds very cool.
Thanks. Testing will prove if it’s a good or bad idea
Was just a concept we came up with out of no where that got some interest. R&D project right now to see what we can come up with.
Have you considered integrating the thruster(s) into the amas (floats)? Or is that your idea and I missed it?
Thrusters will be mounted on the bottom of the floats, probably a couple inches below on an extension pipe. The pontoon itself will probably only be 1-2" in the water so figure thrusters need to go a bit more below to ensure they maximize thrust and don’t surface, so probably 2-3" below the bottom of the float, but will tweak in testing to try and keep them as close as possible.
If you’re designing this to work with a variety of kayaks, you might want to consider making the “wings” adjustable for various amounts of freeboard (height of the kayak deck above water.
Perhaps make the floats deeper and integrating the top of the thruster into the bottom of the float? A pipe would add drag.
So the idea is this would replace paddles, right? And you would use a joystick to steer / control thrust? You might also be able to steer by leaning your body weight left or right. If you haven’t tried this before you might be surprised at how well it works.
More to supplement a paddle for trolling when fishing or heading across a lake etc, than totally replace it.
The main support tube will be mounted to one of the Scotty rod holder mounts to allow for adjustment up and down as well as ability to folder them up and back for storage when not in use.
So basically you would lower the “wings” down until the floats are self supporting on the water surface or approx and tighten into position. The floats will probably only be in 2" or so below surface.
The pipe mount for the motor is only going to be 2-3" and 3/4" diameter so minimal extra drag. Having the floats deeper I think would cause more drag than the pipe.
Concept is similar to this in terms of mounting to kayak.
Here’s a super rough sketch of what I’m talking about. Rather than hanging the thruster from under the float, integrate it into the bottom of the float (ama). Several advantages to do it this way: there’s less drag, reduced overall draft (how deep will your thruster be? will you need to walk the kayak out to waist deep water?), less lever arm so your kayak mount and wings won’t be under as much stress, and I think it could look better (better esthetics).
Understand you idea but would make the pontoon floats a lot bigger I think. The thruster bottom will only be about 6" from the surface and they can be deployed out from the boat but just lowering the wings, it will only be a few pounds overall.
To have the thruster in the pontoon it would need to be drawing a lot of water itself.
With only 10-12lbs of thrust on the pontoons there wont be a lot of stress. This isn’t moving at high speed.
But this may all have to be rethought once we start testing. The thruster idea may not work at all.
Ideally the thruster will be right on the bottom of the float but I expect it may need to be lower to ensure it remains below the surface.
… perhaps not much stress from the thrust of the thrusters but if you ground the boat or hit something, the stress could be substantial.
There is enough flex in the pipe and mount that it shouldn’t be an issue but is a potential but again at 3-4mph it shouldn’t be a major impact. It is not a solid ridged system.
Others are using kayak setups with pontoons with trolling motors now so the actual overall concept has been used, more just a different approach and different design.
Could possibly add a fin fore and aft of the motor to act as a skid plate to help avoid grounding impacts.