Converting a metal detector into submersible unit for offshore detecting?

[ozzysdad]

I know it might sound crazy, But, Why couldn't a person take an older metal detector and strip it down and incorporate the coil and circutry board inside a 3 or 4 inch schedule 40 PVC tube, Cap one end and use a removable threaded plug, and adjust your setting's for what type metal your looking for, Replace the threaded end cap with teflon tape and use a nylon type rope and run the speaker wire adjacent to the nylon drag line, back to the deck of the vessell to a stereo pre-amp and crank the volume and listen for your signal's? Seem's like enclosing it in a PVC tube would protect the circutry and using a stereo pre-amp to boost the return signal's would be considerabley easier method than all the other hassle of building a circut board and using the coil connected to the end of the pvc pipe or directly centered beneath by some form of suspension. Sound's feasible enough?
Would be easy to find a good older metal detector for next to nothing. Wonder if it might be worth the go? Please, anyone else have any thought's or idea's that might be supportive of this, Any replie's, positive/Negative? Point/Counterpoint? would be appreciated.


Thank's, ozzysdad.....

 

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[Floater]

I like it OD. Check my battery pack under the technical thread. heres the link http://forum.treasurenet.com/index.php/topic,10168.0.html

The biggest proble you have is making sure the coil connector is waterproof and the speaker wire connector is to. This should not be this hard. The only other consideration is the length of cable to coil. I dont know if this will effect the signal or pick up. You may need to upgrde the wire for resistance from the board to the coil itsef.Let me know. Als ther is a thread about Rovs that deal with a lot of this and do a google search for homemade ROVs Good luck and keep us posted.

 

[mgdigger]

I like the idea and have been thinking about turning my old garrett freedom two plus into a water machine. May try your idea.

 

[ozzysdad]

Thank's Floater,

I wondered about the resistence change by extending the lead from the search coil to the actual circutry. Thus, the reason for the extension of a speaker wire connected from the headphone jack up through the hull top dead center and sealed with silicon and a layer of epoxy on top of that, It might also be wise to use a relaxable or coiled lead from the jack thru the hull(you know, like a telephone cord, that is flexible and would allow you some slack should you need it in the event you get snagged or the tow line was to break? not to mention i have seen where you used to be able to buy those 30 ft. telephone cord's for a more than reasonable price, plus they have 4 wire's. I would think you could get away using two lead's for the speaker jack and the other two lead's to the power connection. As i recall the juice required for a telephone is max. 24 volt's, my detector take's 2 9 volt batterie's, I would also think the phone cord having such a small guage wire you wouldn't need to worry so much about resistence over that length of wire. A little more food for thot.....,by leaving enough of the coiled wire inside the tube would allow you to easily slide the circutry board out for any adjustment's. As for the search coil, a little silicon and epoxy it will be waterproof...

 

[Floater]

I hear ya Scratchin. The snag situation shouldnt worry you too much. Remeber you gotta drift just about. the only reason you need power is to stay the course. other than that you will be crawling. A good 8" water vue tube and you are good to go. (if the water is clear) The cable sounds about right. but dont coil it up to close to the circuit board you will get interfernce. Remeber that coil is on the outside and awy from the boards as a dry unit so the same applys. Later. HH

 

[Monty]

Three words, con den sation! Unless you seal the unit with some kind of gas (much like a riflescope) or somehow vacuum seal the unit you will eventually get condensation which will in short order eat up or short out your circuit board. How do I know this? Take a piece of pvc and seal both ends. Put it in your refrigerator and then take it out and let it warm up. Open it up and pour the water out! JIM

 

[Floater]

Three words, con den sation!? Unless you seal the unit with some kind of gas (much like a riflescope) or somehow vacuum seal the unit you will eventually get condensation which will in short order eat up or short out your circuit board.? How do I know this?? Take a piece of pvc and seal both ends.? Put it in your refrigerator and then take it out and let it warm up.? Open it up and pour the water out!? JIM

Jim your a little late on the post but Thanks for the tip. I think Ozzy was going to use a threaded end cap so he could check it. Minelab just uses a small condescent bag in the unit.Never had any problem in mine and the housings have removable ends. HH

 

[Maggot]

Neat idea, I might do that with my crappy pioneer 101 after I get my new one. I am sure there is a way instead of running a line for speakers, make it into a light or vibration unit.