Payload: Food Canon



Have you ever seen a gannet plunge-dive into the ocean in search of it's next meal?

I am toying with the idea of adding a "food canon" payload to the ROV in the hopes of releasing food at depth to attract the gannets into the camera's field of view. The on-board depth sensor would then allow us to answer rather accurately "how deep do these gannets dive"?

Here is my concept. Lets call it, Food Canon Rev.1.

The Canon consists of a hollow tube, a plunger and an actuator. The tube is of course where the food will be loaded, and the actuator (rubber band in this case) will force the food out of the plunger when the arming pin is pulled. I believe the pin could be pulled using something similar to Hub's fantastic Magnetic Coupled Grabber seen here ( )

I played with other ideas including a screw auger type of mechanism to load/unload the tube via rotating motor, using springs (which I may yet try) and settled on this design as a first go.No 3D printer... no problem; Picture using a syringe to essentially accomplish the same thing. Thinking more about the task at hand I think syringes would be even better than custom parts. (update: Hub has since posted almost exactly what I describe here. His system is used to collect water samples; I would run it in reverse. I love the collaboration opportunities the internet facilitates. )

There is further write up of the concept over on OpenExplorer. Check it out at Wander there to read the details and then come on back to offer some feedback and commentary.


It's amazing how quickly the ideas for improvement come when you get a physical part in your hands. " if only we tried this..... Aha, of course!" The beauty of rapid prototyping; "Fail fast, fail often"

I've changed the plunger to: 1. eliminate the binding of the rubber band 2. eliminate the screw and two-part plunger The change, while minimal, has made a nice difference. Here it is....


cool thing, but this will most likely only attract swimming gannets a meter or two below, or fish. do it the Norwegian way if you want gannets to dive realy deep. use a herring or other "shiny" fish on a stick.

when we sometime get gannets in the fishing nets they dive for the shiny reflections from herring.


Thanks for the tips Imn.

So what I really need is a sneaky Herring Deployment At Depth Device. HDADD LOL!


make it bigger and put a herring inside?


That might work. :)

Apparently, the gannet population seems to be in trouble off the coast of Newfoundland. See the details on this post from a few days ago.

I imagine one day the OpenROV community will be credited with doing their part to save our oceans. :)