Re-setting dock anchors

[Paddy]

Hi all

just wondering if anyone here has a group floating dock. Our dock has 12 slips and has 4 concrete anchors criss-crossing under the dock at 45 deg. This is to allow for some water fluctuation. But with large water level changes, the cable must be brought in or out as needed. If you don't make adjustments for high water, the anchors get dragged closer to the dock. This allows for the dock to swing a bit.

So, we need to reset because we did not keep up on this : (

At this point I don't know how heavy these weights are. I have an old pontoon boat and thinking I could drill a hole for the cable in the middle of the deck. Then wench it up a foot or two and back up 10 feet.

Concrete weighs 55% in water compared to air. Not that matters much, the anchor has to hold a 12 slip dock.

 

[bcp]

LOTS of floating docks around here, but I haven't seen any anchored that way. It seems they all have pilings alongside the floating dock, with a steel hoop going around it. No adjustments needed.

With what you have, if the pontoon boat won't lift it, you may be able to add a bunch of empty barrels for more lift capacity.

Lift from the center so you don't flip your boat.

How large is the lake, and how deep? There may be other options.

Bruce

 

[arkydog]

in arkansas on bull shoals and norfork lakes (CORP OF ENGINEERS) thay all use 4000lb concrete anchors. you just have stay with it as the lakes go up and down. every once in a while one dock will drag an anchor and had to be reset. they usually use divers with lift bags and set them behind some structure underwater. you really want them to move so that they don't damage the docks. the other help is to make your cable longer, more give. just this spring the lake came up 14 feet in two days. thats more than the dock is tall. i have slept on the dock before and moved it every 2 hours when the lake rises. good luck with it.

 

[Norm W]

Depending on the depth of the water you could add a 100 lb block of concrete half way down the anchor line. We had floating docks in 60' of water with a 3' rise and fall with the tide. A cubic foot of concrete on the 180' of half inch chain and the docks only moved up and down, not in and out with the tide.

 

[Paddy]

Norm,

The weight at mid length is how sail boats are anchored so to speak. The first x number of feet is heavy chain with rope for the remaining length. so in middle conditions, the end of the chain is the anchor. as a wind tugs at the boat, the chain must rise to make a straight/taught line. Kind of like a shock absorber. We can have 15 ft of rise and fall in our 20 ft normal depth lake.

 

[Paddy]

arkydog,

Sounds like you are all over it. We have done nothing in 10 years but now will have to pay the piper to have them reset. I'd like to think we can have a summer and winter setting. During the summer is normally normal pool height. Then during fall to spring, it goes up and down as the corp of engineers see fit. It does hurt if the cables are slack in the winter with the water lower, just will be a bit crooked in relation to the shore. I wish we couls have two pilings at the end but it would take a monster size piling to take the bending loads with ice blowing.