Friday, 18 May 2012

home-made jigging machines?

I've got a list of jobs to do on the boat that will take me all summer. However, at the end of the summer, the boat should be really sea-worthy, and ready to take me places.

Meanwhile, I've done a bit of fishing on a friend's boat - jigging lures over wrecks to fill the freezer and offload excess fish onto my neighbours. Plenty of fish, so long as you find wrecks that are far enough offshore not to have been emptied by charter boats and the commercial guys looking for fishing grounds closer to port.

It's got me thinking about having another shot at fishing from my cat when I've fixed it up. There's a lot of work involved in sailing to the fishing grounds and fishing without the use of an engine. Too much work, unless I had a lot of crew who could all handle a sail boat efficiently, navigate and fish. And that's unlikely to happen. I've been thinking about reducing the work involved with the fishing, and got round to considering jigging machines again.

When you're wreck fishing, there's a bit of a pattern as to when you catch fish. No fish when the tide is slack, and usually none when the tide is in full flow. The fish bite (cod, pollack and ling anyway) when the tide gets over half a knot or so, and it usually tails off towards full flow. And once the fish are biting, they are all at it. One fella gets a bite, the rest of us are expecting a bite any moment, and it's common for several of us to be all pulling in fish at the same time even though we might have been an hour or two without a nibble.

So there's a window of opportunity opens for a while, and you want as many lines down as you can get down without so many that they'll tangle each other. There's the time of the tide to fish, and then there's the place. You need to be close to or over the wreck. 100 metres or so downtide of it, and it is time to move back uptide. Lines up - move uptide - lines down again for another drift over the wreck.

If the fishing could be automated and I was reduced to dealing with the catch and sailing back uptide for another drift, I reckon that would be do-able.

But jigging machines are expensive £2000 - 3500 each. I'd need at least four. I think there's enough room on my boat for eight. I can't afford that experiment!

So I am considering making my own. The control can be provided by a computer - I'll have a low power PC onboard by the end of the summer, but a laptop would do. I've spent years programming computers, so creating the software is no problem at all. One computer controller several jigging machines has a few advantages - one button press can command all machines to wind up at the end of a drift, and another button press can make them all start fishing at the start of a drift. Catches can recorded easily - everything into a database creating a record of every catch, exact position, tide state etc. Variations of jigging actions can be tried out, and all lines can switch to the method that is most successful. So software not a problem.

I've spent quite a bit of time recently working with CAD, so the physical design isn't a problem either.

Hardware? I need a motor, a line tension sensor, and some sort of controller to communicate between the sensor and motor and the computer. And for more than one jigging machine, a controller to control the subordinate controllers.

I can start with one jigging machine, and see how that works, so it won't cost much to try it out.

So, between my days fibreglassing and so on, I intend to spend some of my evenings researching motors, sensors and controllers.

I'm open to suggestions! (Anyone got a jigging machine? What sort of motor is in it? :))

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