Begin thinking about how this clip might work. The first iteration used an existing outrigger release clip. Why re-invent the wheel? Perhaps leveraging existing mechanical designs would speed things up. This was combined with an RC micro servo and little rig was printed to hold the two together.


Build the necessary hardware for each end of the device. There would be a handheld controller to release the clip, as well as a receiver on the clip. The handheld transmitter uses the Xbee pin mapping to report the state of a momentary switch. The receiving Xbee on the clip reports the pin state to an Arduino Mini, which in turn handles the PWM for the micro servo.

It works like this:

Put it all together:


Ok. So the basics are done, we have a woking prototype of the release clip. However, the use of the outrigger clip was problematic for a few reasons. First, it's really fussy to use. Imagine trying to get a line in that clip on a rocking boat with people screaming at you. Also, there is a frantic mackerel flipping and flapping away on the end of the line. It would be tough. Second, the outrigger clip is designed to let the line slide freely through the pulley. This means that there is less control in determining how far the bait will hang. And finally, there are just too many sharp angles and little bits for line to get caught up in. I needed a better solution.


I decided to try and 3D print the entire clip. I was not sure how to make the tension on the clip work appropriately so I just experimented with different shapes and forms, moving groves and ridges in an attempt to create a clip that would snap shut, but pop open when pushed by a servo.

Here are some iterations. It started with a more organic form, but as I dealt with tension, stability, and actually inserting a standard servo, the clip evolved into this blocky kind of thing that seemed to function well.


I settled on this as the final form. The clip is printed in two pieces and then just snapped together. I used some adhesive backed foam to add some grip and give. There are a variety of line weights that might be used when fishing, so I needed a flexible clip that could grab a variety of diameters. The clip is also rounded to eliminate any stress on the line during the process. If you hook a 180lb tuna, the last thing you want is a kink or minor imperfection in your leader, it will snap and everyone will be very sad.

Here is the final clip attached to a DJI Phantom 4:


I figured it would be a good idea to test this whole process on dry land before trying it over water. A water bottle partially filled is about the weight of your average mackerel.

Wait... What? It worked.....


The tuna season came to close before I had a chance to test this in the wild, but I did test it out on the boat. Unfortunately, my micro SD card decided to take a dump and I lost all my footage. I'm in the process of recovering it. Really sucks.

Here is the only clip that survived. It was a quiet day, no monster tuna was hooked.

In the next iteration of this project, I think the mackerel will be put in a holder or tube of some kind. I mean, poor little fish... The dangling is not so nice. But then again, neither is fishing for large tuna.


Here is the same setup rigged for a SwellPro waterproof drone. The servo is waterproof, so the drone can land in the water. Personally, I prefer the Phantom 4 as it is really easy to land back in your hands. The SplashDrone is a very unreliable. And, it turns out, it's not really waterproof. The only good thing about this setup is that the drone has a servo port available, so no external controller is necessary, we just use a switch on the drone transmitter to release the clip.