anchoring a floating dock

[Megunticook]

Anybody here know how to properly anchor a floating dock? Got a situation with my in-laws where they have a dock on fairly protected salt water, 10-foot tides, and are set up with a ramp connecting the fixed dock to a float that rises and falls with the water. The issue is the float doesn't keep its position relative to the dock very well in wind/waves, and doesn't float level either (lists to the front side opposite the dock). It has a pair of chains that cross over each other connecting two corners of the float to the dock, but in the front the chains don't appear to cross, they just drop straight down. I'm thinking these should also cross. I'd like to help them get it set up correctly but am not knowledgeable in this area and not finding a lot online.

There's a caretaker who sets the float each year and removes it each fall but I suspect the job is not getting the attention it deserves--I noticed that the chains on the shore side are badly rusted down to maybe half or less their original diameter. Not a good sign that those were put back into service this spring--seems to me a good blow could snap one or both of those chains, which would probably do some expensive damage to the ramp when the float starts wandering around.

Any advice welcome, or if you know a good resource please give me a link.

[mgphl52]

Hopefully someone from around Lake Lanier (outside of Atlanta) will chime in. I know there are a lot of floating docks there due to lake level changes. All of the floating docks in my area have pilings with rollers attached to floats.

[wikakaru]

It has a pair of chains that cross over each other connecting two corners of the float to the dock, but in the front the chains don't appear to cross, they just drop straight down. I'm thinking these should also cross.

Up here in Maine it is common practice to cross both sets of lines as you describe, not just the set leading to shore. It is just like tying a boat to a dock with spring lines: the longer the lines, the less change in position there will be as the tide rises and falls. Crossing them gives you a longer length and should keep the dock in position better.

You can sort of see the both-lines-crossed method in a drawing at this site: http://www.alphamarineinstallations.com ... docks.html

and this one...
http://www.kroegermarine.com/sea-flex-mooring-system/

[Megunticook]

Up here in Maine it is common practice to cross both sets of lines as you describe, not just the set leading to shore

Thanks for confirming what I suspect is the main problem with this setup (it's in Maine, by the way). Not sure why those front chains weren't crossed--the caretaker has been doing this for decades, and his father before him.

I'll see if I can intervene diplomatically (not easy as one of the "in-laws") and get this problem fixed.

[Joe CD MS 300]

It’s the ramp attached to a pivot point of some type on the float? That should also help with the position of the float in addition to the float chains. You might want to check the connection of the ramp to both the float and the fixed pier including any iron / steel parts and the wood or timbers it may be attached to.

The listing of the float might be due to the flotation under the float deck going bad. May be a separate isssue from the chains.

[Megunticook]

It’s the ramp attached to a pivot point of some type on the float?

The ramp swivels up and down on a steel pin at the end of the dock, and has small wheels that allow it to roll on the float as the tide rises and falls.

The listing of the float might be due to the flotation under the float deck going bad. May be a separate isssue from the chains.

Could be. If it only listed at high tide I'd say those front chains were too short, but it seems to list at all tides. Maybe this winter when it's out I can have a closer look at the flotation.

[Carl Thunberg]

I have the same type of float system. My chains do not cross. They go diagonally to mooring blocks. One side is fixed and one side is adjustable. Assuming your inlaws dock is constructed similarly, one of the boards on the float should lift up giving access to the chain. There is a slot that fits the chain links. Shorten or lengthen one or two links at a time and see if that helps. Of course that assumes your chain still has some life left in it. They don't last forever. It wouldn't hurt to go for a swim with a mask to do a quick inspection.