Time for an underwater detector-But.....

[Mikemonster]

But which one? Minelab? One of those square thingy's? Kellyco has me confused.

I don't want to waste my time underwater nor do I want to spend 8 grand on a detector.

What unit would you recommend?

Something I could tow slowly behind a boat then use it hand held would be great.
Gosh, sounds like I'm talking about my wife. But she doesn't swim.
Now I have an idea. I'll get back to ya.