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Dock for lake needs anchor ideas...

jonathan_gurrie's picture

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Would you, dear reader, happen to know of a sensible method of securing dock posts (in fresh water) to a lake's bottom? Think of a six pitch roof; this is the slope (underwater), upon which the posts/poles must rest. I have been told the "concrete-filled 5 gallon bucket with post" approach as well as having seen the disasterous insult to the concept of "plumb" of the "just pound the posts/pipe/poles into the lakebottom" way. I would prefer not to get into the hydraulic cement ballgame... Any ideas??? I only need to sink and secure two or four posts -- the above water, wooden portion I can build just perfectly. Oh, and another thing... I want to keep this reasonably cheap. Thanks for your time...
jonathan

(post #163627, reply #1 of 12)

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jonathan.. i don't see what teh slope of the bottom has to do with it..

the "piles" can either be jetted or pounded... or a combination of the two...

if you don't drive them deep enough .. the ice will just pull them out....

hire someone to set your piles and then take over from there....

(post #163627, reply #2 of 12)

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Jonathan, there is a lot of info missing from your request.

what type of bottom are you dealing with?

Is there any current?

Are these taken in and out?

Any ice conditions?

I have mine resting on the bottom with a pad to spread the weight. My basic structure is steel, but i have one section made of 4x4 posts. I simply nailed a 2x6 x12" long on the bottom to spread a little weight around.

I leave it in all winter. The ice knocks the posts out of plumb and I knock them back each spring.

blue

(post #163627, reply #3 of 12)

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How about a floating dock? No tides in your lake or drastic swings in water levels? You could anchor the walkway to dry ground and just let the rest hang out.

Read an article a long while back about using rock filled cribs to support a dock. Don't know how or if that would work on a sloped bottom.

(post #163627, reply #4 of 12)

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We used the "5-gallon tar bucket filled with concrete" around a Locust post, and it's lasted 30 years. However, our bottom slope wasn't as steep as yours. Could you cable the bottom of the posts to the bank-end of the dock? The aluminum (or something similar to aluminum) guy wire used by the electric utilities would hold up underwater very well.

We used oak planks under water to stabilize the posts. I don't think the posts would have slipped even with the slope of your lake bottom. But...ever try to drive a nail underwater through an oak plank into a Locust post? Don't. Use galvanized bolts or lag screws. Predrill the holes, and of course don't be doing the drilling while you're in the water.

(post #163627, reply #5 of 12)

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I built a deck on solid ground with a cantilever over the water....built the dock with foam blocks under so it would float. Attached to deck with line... drove two metal posts eight feet out as guides for the dock to fit between. I can now untie the dock and row it out to the deeper water and swim off it. Very nice.

(post #163627, reply #6 of 12)

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I suggest jetting in the posts if you do not have a rocky bottom. I live in Florida and have built a 210 foot dock and a 100 foot bulkhead. I jetted in all the pilings,and they were 9 inch diameter and 10 feet tall. You can rent a jet pump with 1 1/2 inch outlet hose attached to a 3/4 inch galvinized pipe and pretty much punch a hole to the center of the earth. If your posts are smaller,and you're only doing a few,I would try a garden hose attached to a3/4 inch pipe as long as you need to hit the bottom,and narrow the end by pounding it almost flat.Set your posts in position (have someone hold it reasonbly upright),then squirt the jet on the lake bottom. The post will glide into resulting hole.

(post #163627, reply #7 of 12)

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Lots of info missing, biggest is just whether you need to cope with ice. If the slope of the shore where you are putting the dock will allow the cheapest way is to build a floating dock. Lots of things to use as floats; plastic barrels, foam blocks, etc. You just need to look around and price.

To keep the dock in place just drop a couple hunks of concrete on the lake end with cable and floats. Then tie to them. The shore end is tied to pilings. If ice problem just drag it out in the winter. If no ice problem just let it stay.

Cheap, easy, and does the job.

(post #163627, reply #8 of 12)

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I would be happy to donate my mother in law to anchor the dock. She has plenty of size and weight. Just a thought.

(post #163627, reply #9 of 12)

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What you do is tie about 4' of strong string around a .50 caliber bullet and tie the other end to the end of your pile. Then you insert the bullet in your handy .50 cal machine gun, point it at the spot on the lake floor into which you heartlessly desire to install the piling and pull the trigger. The bullet goes deep into the lakebed. The string drags your piling with it and, presto, you're done.
-Peter

(post #163627, reply #10 of 12)

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Jonathan: I have taken on a project to replace a floating dock with a fixed dock on a 11/2 ac pond. I plan to use a 6" auger post hole digger to bore a hole in pond bottom using floating dock as staging. The post hole digger I purchased uses 3/4" black iron pipe to attach handle to auger. My plan is to get several lenghths of pipe up to about 10' to use to make hole progressively deeper (approx. 3' below pond bed). Insert 6"pvc pipe to approx6" above spillway grade drive rebar cage into bed & pour. Then fix dock joists to pier using metal flanges. My concrete man assures me that when poring concrete in pipe excess water will be displaced. Concrete footers will then be poured above waterline to anchor dock to "shore". Thats the plan anyway. Pond is about 6' deep at proposed pier site.

(post #163627, reply #11 of 12)

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Millsie, if she's that heavy, wouldn't she float from all the fat? Could be an alternative to foam or barrels, though....

(post #163627, reply #12 of 12)

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Would you, dear reader, happen to know of a sensible method of securing dock posts (in fresh water) to a lake's bottom? Think of a six pitch roof; this is the slope (underwater), upon which the posts/poles must rest. I have been told the "concrete-filled 5 gallon bucket with post" approach as well as having seen the disasterous insult to the concept of "plumb" of the "just pound the posts/pipe/poles into the lakebottom" way. I would prefer not to get into the hydraulic cement ballgame... Any ideas??? I only need to sink and secure two or four posts -- the above water, wooden portion I can build just perfectly. Oh, and another thing... I want to keep this reasonably cheap. Thanks for your time...
jonathan