So I'm contemplating building a floating dock on a friend's lakefront property for a 23' boat. It's on Lake Simcoe
, north of Toronto, which is about 30km across and big enough to get a couple feet of wave action in storms.
After going through everything I could find online (a pile of eHows
- see the related articles on the side, and a couple other places) the floating structure is straightforward and what you would expect: build a box of 2" x 8" x whatever, maybe put another stringer or two down the middle, brace it regularly with crossbeams, plank it, attach floats (don't forget to work out how much buoyancy you need), voila! Use appropriately sized marine-grade hardware. If you can build a deck, you can build a dock (just one letter apart ...).
But none of the suggestions online go into great length about keeping your dock in place on a lake with some wave action, especially with a heavy (maybe as much as 2 ton?) boat on it.
What makes sense to me would be to pour some big old concrete slabs shoreside, like you would for wooden deck posts. But instead of a 4x4 or whatever vertical, set a heavy-duty metal shackle into the concrete (hopefully on a base with a lot of surface area, not just a screw). Then run chain out to the base of the dock. Use a short hinged "gangway" section to connect the floating end of the dock to shore. Maybe also sink extra slabs a little ways out to the right and left and run diagonal chains attached to the dock 20%-25% of the way out (i.e. still in water too shallow to be the "usable" portion boat-wise) to counteract the otherwise serious lever arm that lateral forces on the end of the dock would have on the anchor points at the base.
Any thoughts? Anybody tried it?