How to dig in water?

[chlsbrns]

I have been looking for a specific buried treasure based on old archived newspaper articles and have found a location & evidence that warrants digging.

It's made of iron and rectangular about 21" x 14" My Johnson magnetic locator detects down to 20 feet on an object that size. My metal detector doesn't signal at all on the location.

A Johnson magnetic locator has 8 sensitivity settings. I get a weak interrupted signal at the lowest setting, a steady signal at 4 and a strong signal at 8. I'm guessing it's about 10 foot deep.



The problem is that the location is under a few feet of water for hours & the buried object is deep. It's tidal water. How would you dig when there isn't enough time to dig a large enough hole in-between tides?

 

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[63bkpkr]

Not knowing squat about the subject but the first thought that came to my mind was that it needs to be planned so that the proper tides will assist you. 10' deep is a very long way down in wet sand and I would Never climb into a narrow hole in such conditions as the chance of a collapse is very likely.

I would practice to see if I could get the tide in the area to help by digging a hole close by and see if the tide will help dig it out, probably just refill the hole but it could be worth a shot. I'd wait for a time when there was going to be a large minus tide and use a front end loader to dig into the site by digging a road into the site but 10' down is a deep hole. Be safe...................63bkpkr

 

[chlsbrns]

I should have provided more info. I'm guessing 10 foot. It's a small island in the back bay so the backhoe is out of the question. Wakes from boats are also a problem. The oldest aerial photo at historicaerials.com was in 1920 and shows that the island was at least 2x larger in 1920 than it is now. The area where I have to dig was at least 30 yards away from the water in 1920. A neighbor suggested using a gas water pump & jet to probe straight down to see just how deep it is. Depending on the depth of the item the water jet may be able to uncover it. I'm going to have to find out about laws & such to do something like that though.

 

[doc-d]

There are experts on this site who can better guide you......whatever you do, have somebody else there with you.......wet sand is dangerous and boat wakes make it more so.......don't go into any hole without a line attatched to you.......
Good luck!

 

[Jason in Enid]

If you can't dig to recover it, how did the person dig to bury it?

 

[chlsbrns]

If you can't dig to recover it, how did the person dig to bury it?

It was buried in the 1700's. As I previously stated a 1920 aerial photo shows that in 1920 the island was larger and that the dig site was at least 30 yards from the water in 1920.

 

[Jason in Enid]

If it's sand, it still would have been below the water table.

 

[chlsbrns]

Do I really need to post this?

There is a huge difference digging inland & digging in tidal water. Digging on a sand beach is a whole lot different than digging under water.

 

[doc-d]

If the land is 30' less from the 1920's.........where was it in the 1700's

 

[chlsbrns]

If the land is 30' less from the 1920's.........where was it in the 1700's

I found a 1873 map. The map shows it a whole lot larger in 1873 than it was in the 1920 aerial photo. An 1888 topo map shows that the channel that is causing my problem didn't exist in 1888.

 

[393stroker]

You would have to build a dike around the dig area to keep the water out if it is under water. Still you would have water coming in from the sides, so you would have to work fast. We use these where I work to dig holes for concrete sometimes. You would have to run some 6" corrgated plastic hose(ADS) from the truck to the spot. It could be done. It sound like a safe or something.

 

[Red James Cash]

You need a cofferdam.