Electronic retrieval of a crab fishing net

Hello all, I am working with a professional fisherman in a Central Queensland Fishery that is loosing approximately $120K of equipment and produce annually due to fishing equipment being stolen and fish being taken and wants to try and develop a “rope less Fishing system” Queensland fisheries as do all other fisheries in Australia require visual markers on all fishing pots so as the pots are soaking, the equipment and the seafood catch is extremely vulnerable to being poached.
I believe that I have found a way of getting a signal to a receiver via ultra sound and I have attached some tech data in the images above. Please bare in mind that I am not a technical person and I don’t understand a volt from an amp however I know what I would like to achieve. If I have a crab pot with the receiver attached, can I convert the signal to activate a solenoid valve to refloat the pot. I invisage a pelican case that will house the electronics. We are only fishing up to 12 meters in depth. The retrieval can’t be on a timer because of changing weather events etc…
So am I any chance of raising a pot via this method. Thank you all for taking the time to read this.
Terry Gillam

Hey Terry,
Welcome to the forum!

That sounds like something similar to what is used currently for marine salvage, I believe it’s called a buoyancy bag.
Maybe have a look into some products that are used commercially in that area for some inspiration on how you could go about this project.


Hi Terry
I don’t know how anything like this is going to get around the requirement to mark the pots.

To use ultra sonic signalling you would have to be careful of interference like just about every boat afloat uses echo sounders for fish finding and just keeping an eye on the bottom. The larger commercial vessels run into lots of watts and are quite powerful. The last thing you need is all your pots surfacing every time a ship goes past. I think there are other beasties like whales and dolphins and probably more that use some form of ultra sonic signalling.

Probably worth a try though. You might even be able to modify an echo sounder to code the “ping” so your pots only respond to that code and ignore stray signals. It has been a very long time since I had anything to do with those things so don’t quite know how you would go about it.
Cheers Bob

Cheers Bob