Anchoring a dock

[eriks]

Does anyone know about anchor blocks and chain layouts for anchoring a dock in the ocean? I’m looking for information on how to properly anchor a single dock (12’x36’) to deal with our tides and some small waves from local storms.
I’ve searched extensively on line but not found anything yet.
Thanks!

 

[zurk]

copy the submerged cable anchor system from here : https://www.fs.usda.gov/t-d/pubs/htmlpubs/htm02232812/page07.htm
repeat every 12' - so you will have 8 concrete blocks of 2.5' x 2.5' x 2.5' each which is 2100lbs per anchor point. should be enough to handle pretty much anything in the 30 foot boat range. make plywood forms for pouring the blocks or just buy the "half block" of concrete commercially (ask them to put rebar for the hook eyelet which goes through the block completely). if youre pouring it then just use a + rebar form at the base and run your chain through that and through the whole block. dont bother with an eyelet.

 

[Foxsea]

The anchoring arrangement zurk suggests is great. If you pour your own anchors, shape them like pyramids. Even though concrete has a mass of about 150 pounds per cu.ft., sea water has a buoyancy of 67 pounds per cu. ft. The effective mass is significantly reduced. In a muddy or sandy bottom, the pyramid shape buries itself and the holding is massively better. Heavy chain, embedded in the concrete, with the reinforcing threaded through it, is a good connection. Use epoxy coated bars and sulphate-resistant cement to batch the concrete.