Introduction: Building an RC Feeder Airboat for Fishing
This is a story about failure and how I managed to iterate on the design process so I can fix my mistakes.
For some time now, I wanted to make a boat that I can use on my fishing trips where I can use this boat to pull the fishing line out on the water, beyond what I can cast by throwing and to also serve as a feeder boat to bring in extra food to the cast place for when catching carp.
When thinking about the design of the boat, I chose to make an airboat because the lake where I usually go fishing has a lot of grass growing in the shallow water, so any propeller or anything else sticking out of the bottom will become tangled and the boat can get stuck.
Below are the two videos of the entire process. The first one is the initial making that at the end did not work as expected but then after fixing the issues, the boat worked perfectly even while carrying a lot of weight.
Tools and materials used in the video:
- A2212 RC Brushless Motor - https://s.click.aliexpress.com/e/_d8VTDRx
- 30A Brushless Motor ESC - https://s.click.aliexpress.com/e/_dVRbIZL
- High power servo - https://s.click.aliexpress.com/e/_dXqayPr
- 9g servo motor - https://s.click.aliexpress.com/e/_dWBgW4v
- FlySky FS-i6X RC transmitter with FS-i6B receiver - https://s.click.aliexpress.com/e/_dXH8DMz
- 2200 mAH 11.1V Li-po RC battery - https://s.click.aliexpress.com/e/_dWsq0jn
- Li-po low voltage battery alarm - https://s.click.aliexpress.com/e/_dX7EKff
- RC replacement propellers - https://s.click.aliexpress.com/e/_dWyGB5X
- Utility knife - https://s.click.aliexpress.com/e/_dTkZJpB
- Hot Glue Gun - https://s.click.aliexpress.com/e/_dSGObPL
- Hot glue sticks - https://s.click.aliexpress.com/e/_d6FCekD
- Stainless steel ruler - https://s.click.aliexpress.com/e/_dTl8dP3
- Mini drill - https://s.click.aliexpress.com/e/_d8lfagt
- Machinist square - https://s.click.aliexpress.com/e/_d7MBCl7
Step 1: Prepare the Airboat Platform
The platform of the airboat is made out of corrugated plastic that is typically used for roofing and it has a lot of rigidity.
To determine the shape of the platform, I've placed the plastic bottles that will provide the buoyancy on the front and the back and I marked and cut a sort of pointed shape out of it.
The bottles are then glued to it with hot glue and for the sake of making sure that they don't come off, I drilled holes next to each bottled and tied them with a garden string.
Since there was a bit of flex in the direction of the ribs on the plastic, I've added a piece of wood, perpendicular to them that is held in place by screws and hot glue.
This added a lot of strength and made the entire thing rigid.
Step 2: Make the Motor Mount
In a typical airboat configuration, the motor is mounted in the back. In my case, I wanted to have the back available for the loading bucket so I decided to mount the motor in the front.
The mount is made out of two pieces of the same corrugated plastic material that I made the platform where these pieces came from the offcuts of it.
They are glued together at an angle to form a sort of a pyramidal shape to reduce drag where the pointed side is in the front and on the back, there is a flat surface to screw the motor mount in.
This is then glued on the front of the boat and a plastic tray is glued behind it to hold all of the electronics.
Step 3: Make the Rudders
The airboat will have two rudder wings to be able to better deflect the air pushed from the propeller.
I made these again from the same plastic material, where I first cut a square out of it and then I split that square into two trapezoidal pieces.
Since the plastic has channels inside it, I used one of these channels to run a steel wire through it that is bent on the top and it is entirely glued to the plastic.
These steel rods will serve as the mounting points for the rudders, so I made two holes in a wood piece to mount it behind the electronics box.
THIS IS WRONG!
By mounting the rudders in the center of the airboat, they are not able to provide the angular momentum needed to spin the boat around. Instead, they push the boat to the side and it is unable to be steered. I'll fix this in a later step, but if you are following along, make sure to place the rudders in the back of the boat so they can rotate the entire thing.
The control horns for the rudder are made out of craft popsicle sticks where I first cut a small length of them, drilled a hole with my rotary tool and then I glued them into a slot cut in the plastic.
Step 4: Connect the Rudder Servo and Electronics
This is a fairly straight forward job as we basically have only two connections to make on the RC receiver.
The motor ESC is connected on channel 3 so the throttle can be controlled with the left stick of the RC transmitter and the servo for the rudder is connected to channel 1 so the rudder can be controlled by the right stick left/right movement.
Step 5: Make a Test Run
Having the controls ready, I wanted to test run the airboat to see how it behaved before I went in any further.
This is where I discovered that placing the rudders in the center doesn't work but you can check out all of the details in the video below.
Step 6: Fix the Placement of the Rudder
Since it became apparent that the rudder must be mounted on the back of the boat, I had to now cut the mounting wood strip into two pieces so there can be an opening in the middle for the bait and the fishing line to be able to pass through.
These two pieces are individually mounted with two screws each and I re-used the same mounting holes as before.
Step 7: Cut the Dump Bucket Slot
The initial plan was to have the loading bucket all the way to the back where there won't be anything to interfere with the fishing line being towed.
Since now the rudder is in the far back of the airboat, the loading bucket will be moved to the center of the boat so a slot is needed in the center to allow for any bait being towed to be safely released in the water without getting tangled.
I first marked the position of this slot to the platform plastic and then using a utility knife I cut it out.
Step 8: Add Skirt to the Underside
In my initial test, the buoyancy of the boat provided by the 4 plastic bottles was not that great as the boat sit quite low in the water.
This is a problem since where we plan to use the boat there is a lot of water grass growing inside the lake and the bottles can easily get tangled on it.
To mitigate this, I've added a skirt all around the boat out of 5 mm XPS that is typically used as an insulation for laminate flooring.
The skirt is glued together with hot glue and I made sure that there are no gaps where water can leak in.
Step 9: Mount the Rudder Servo
To improve the rudder movement, I now made a new mount for the servo motor out of XPS foam so the servo can sit in line with the control horns.
This mount is glued to the airboat platform and the wire is passed through a hole in the electronics box.
Step 10: Mount the Load Bucket
The final step is to mount the loading bucket to the boat and for that, I used a door hinge to serve as the pivot for it.
I used a bit of hot glue to temporarily hold the bracket in place and I then drilled and screwed the thing to the bucket. Since the screws I had were too long, I used my angle grinder to cut them off.
After I found the best placement for it to be able to freely move into the cutout on the platform, I used there more screws to bolt it to the platform.
The tipping mechanism is not done yet but it will be made with a strong metal geared servo motor that will be mounted on the axle of rotation on the door hinge and it will be controlled by a switch on the RC transmitter.
Step 11: Testing It Out and Next Steps
Now with the boat mostly read, it was time for another test run and this time it worked beautifully.
The boat runs smooth and without any load, it even goes quite fast.
We were able to drive around the lake with a large stone in the loading bucket without any issues and bring the boat safely back to shore. You can check how it went in the second video for the project.
As a final thought, if I ever re-do the project I might try and use XPS foam directly for the boat platform as that will not require to create the skirt and provide a lot of buoyancy directly.
If you have any suggestions, please leave them down in the comments as this is my first time building anything that floats on water so I have a lot to learn.
Cheers and thanks for following along.