Search and recovery in silt?

[Adam]

I am looking for tips for searching for a fairly large object on a silty bottom. I am guessing the silt is 5-8 feet deep.

We are thinking of using a metal detector but we are not sure if it will hit on something that is buried in silt.

Another idea we are thinking of is dragging some sort of snag through the silt in an organized pattern.

The only thing we have to go on are GPS coordinates that we taken just after the loss. So I suspect the search area will be kinda big.

Any ideas?