prop washing for a deeper channel

[LongJohnSilver]

For the last few months I've had a lot of silt building up next to my dock and at low tide it is close to being all mud. Usually it stays clear by simply running my motor while coming in and out, plus heavy rain storms at low tide flush it out. Maybe it's because of the drought, but it's building up. Does anyone have any tips or tricks to enhance the removal? I've been told that running the boat back and forth during a falling tide works best. I've also heard of people towing an object behind the boat to stir up the silt.

 

[tashasdaddy]

Re: prop washing for a deeper channel

we use to tie the boat off and let it run in gear, to blow the crude out. the more you use the space the clearer it will stay.

 

[F_R]

Re: prop washing for a deeper channel

Don't know about the truthfulness of this but many moons ago somebody told me that in some river all boats were required to drag a long chain to stir up the mud to be flushed out. The idea just stuck in my head. Now if I could get some of that stuff flushed out of my head. But not everything, please.

 

[beerfilter]

Re: prop washing for a deeper channel

A few passes during a falling tide , with your motor/outdrive trimmed all the way down should move the silt .
Dragging some chain or a small anchor will also help , just rig it with a light line that will break before your cleat , transom , gunwale , in case you snag something !

I'm sure drought caused low flow conditions are contributing to your silt problems , as there would not be enough flow velocity to keep the silt in suspension .

Treasure hunters used to use an "L" shaped pipe to redirect thier prop wash straight down .
It was extremely effective at clearing silt and sand and exposing artifacts .
It was also extremely effective at destroying seagrass beds , so the use of these devices is now illegal .

Good luck , just remember that your "dredging" is a temporary fix , as you cannot alter the hydrodynamic conditions that are causing the silt deposition .
The silt will be back after the next storm or 2 , and you will be back to square 1 .

 

[zkimball]

Re: prop washing for a deeper channel

The State of Florida calls it "Dredging by Agitation" and, strictly speaking, it's not supposed to happen without a permit. To get a permit, just stand in the same line as those waiting for a license to shoot manatees. Good luck!

That being said..., I put the Mickey Mouse ears on my engine, so there's good clean water going through it, and secure the hose so it can't get into mischief. I tilt it all the way down, and tie my boat off to my dock and against my bulkhead in several different positions. I run the engine while turning it back and forth until the amount of silt roiling up drops off and then turn the boat to another direction and do it all again. When the tide goes out, I often find I have a little "lake" under my lift and a load of muddy silt surrounging it. It only lasts a few months though.

My neighbor used to tie a couple of concrete blocks to a 4'X6' piece of chain link fence and drag it up and down our chanel. It stirred up a lot of mud and silt, but I never saw it do much good. Also, depending on the direction of the tide, a lot of it winds up under your neighbors dock! Z