Popular Swimming spot with raft and diving board BUT

[McDyver]

Up on lake superior 100 yrs ago there were LOTS of saw mills and for their first 20yrs they dumped bark and sawdust into the lake before they were ordered to burn it. In the spot I mentioned the sawdust is 2 ft deep or more in about 10 to 12 ft of water. I tried it once but the only things I got were tabs and a few clads, the rest is DEEP. I thought about bringing my boat in there and tying to the dock and blowing a big hole with the prop and let it settle for a couple days, has anyone ever done this?

 

[Lou from downunder]

G'day McDyver,

Now that you mention it, the first gold ring I found was compliments of prop wash.

30 odd years ago I was snorkelling off the front of one of our bayside piers.
On one of the dives I noticed a freshly excavated "gutter", about 3' wide, a foot or so deep and about 10' long and running parallel with the pier.
Old sinkers were everywhere. As I was picking them up I noticed what appeared to be a gold ring, but thought, "nah, could'nt be" but picked it up anyway.
It was a fairly wide band with an intricately carved inlay of a paler material.
My wife took it to a jewellers who confirmed it was gold. The inlay was white gold and he told her it was of an antique design and probably quite old. He valued it at $400, a lot of money 30 years ago.

Thinking on how this gutter might have been created, the only explanation I could come up with was that a fairly large boat had tied up securely to the pier and then put the engine into gear and given it good blast for whatever reason with the resultant prop wash carving out the gutter.
I have seen lesser examples since.

And as for the ring?
My wife had it resized to fit her finger and then promptly lost it!

Cheers.

Lou.

 

[MikeDahms]

I don't have the experience you are looking for. But I have MD'd under water a lot. I have thought about this some and with some small manufacturing skills you can experiment and see if it works. I'm thinking of that plate on the bottom of an outboard motor just above the prop. Extend this out and down, forcing the prop wash down. This will carve ditches in the saw dust. Down here in coastal N.C. the local clammers use a similar device on their boats. It causes the prop wash down as the boat moves forward and they drag a weighted net along the bottom. The prop wash digs the clams out of the mud and throws them back into the net.
There is also a thing called a "mailbox" that was used by Mel Fisher and many other treasure hunters. I don't have a picture to show you but someone here will. Another way to go is rent a gas powered trash water pump. You would have to weigh down the hose to keep it in one area. I think this could be the easiest and cheapest to do. Punch a few holes and get into the water a while later when you get the visibility back. You could better decide if you want to launch a larger scale operation.
There are dredges to consider if it is a very productive area where you can get away with using one. Hopefully I have covered some ideas you haven't thought of yet and prompted some new ideas. I worked a couple of platforms at a salt water beach and it was almost tiring how much digging I did. Best of luck to you, Mike.

 

[pmike]

When I was a kid some friends of our family bought a home with a dock that extended out into the river. The water around the dock had become shallow due to sediment over the years so they were unable to use their boat from the dock. In order to remedy their problem, they used a small boat with an outboard and pulled an old metal milk crate during outgloing tides. Before long they had cut in a channel deep enough to get to and from the dock by boat. I would think you could do something similar, though being a lake there may be no outgoing tide to help flush out the debri. Another issue might be locating a metal milk crate . By the way they had weighted the crate with a cinder block.

Mike

 

[bdahunter]

A mailbox is just a piece of ducting with a right angle turn that is positioned behind the prop so that the force of water is directed down to the bottom. You would have to securely fasten this rig to the transom of your boat or the force of the prop wash will blow it away. Triple the size of the prop for the ducting width would work just fine.
[attachment 106445 Mike20M5.jpg][attachment 106444 Mike20M2.jpg]

Cheers

 

[grumpyolman]

Had a similar issue when diving in Puget Sound looking for antique bottles. We discovered that after some major tide changes that areas that were once absent of bottles, suddenly showed many. We purchased a water pump, attached 11/2 fire hose to the pump, aimed the nozzle into the mud and let it fly. We'd run the hose for 10' at a time, surface, and let the sediment move away. Once it cleared we'd go down and cherry pick the bottles. Sometimes we got lots of loot and sometimes it was a bust. It's kind of like the mailbox only you aren't near any turning props and you don't have to worry about setting bullet proof anchors lest you fly into the beach or another boater. I think the reason the mailbox worked so good for Mel Fisher is he needed to move LOTS of sediment and overburden. Sounds like what you need to move is not as dense or in the same amount. Water pump is cheap and probably rentable for the first try to see if it works.. Jim

 

[McDyver]

Thank for all the tips, I'm a fire fighter and have access to numerous pumps. Next summer I'll blast away!

 

[bdahunter]

n/t

 

[grumpyolman]

McDyver...You know how tough it is to handle a 21/2 by yourself? You'll have a similar problem with the 11/2 underwater. Being weighted a little heavy to off set the pressure of the hose helps. You don't have to run it at 90-100 PSI like you do your work truck for it to be effective. (Been there done that too) It also makes a difference what type of nozzle you hit the muck with. I betcha you get some retired 1 1/2 hose pretty cheap. Probably an old nozzle hanging around you can 'borrow' for a few hours too. If there's stuff there, it's definetly worth the effort to uncover it.
Also you might use a pump underwater using the venturi effect, like on a gold dredge, that could lift the stuff to the surface into some kind of home made sluice apparatus.If you had a big compressor for air, you could also make an air lift to the surface. Just ideas. Let us know what works for you down the road...Jim

 

[rehless]

Be sure you do not run afoul of fish and game. Some places, you have to consider the inhabitants and spawning and all that.