What is the best way to anchor a floating dock?
It depends on the size of the dock and the kind of lake bottom (rocky or smooth), but a common rule of thumb is that you need enough weight in anchors to equal twice the weight of your dock. If you’re putting in these anchors yourself-and assuming you don’t have the strength required to lift and carry three tonnes of concrete in one shot-you’ll probably want to use several smaller weights. Many cottage-country building centres and dock retailers sell pre-made anchors, but you can also make them yourself, by pouring concrete into Sonotubes or into 14″ tires lined with polyethylene sheeting, or by building a simple mould out of wood (also lined with polyethylene). Use 3/8″ steel chain to connect the anchors to each corner of the dock, at 45°.
How many anchors will you need? For a small, straight dock, you’d want at least two, one at each corner. Criss-cross the chains so that the left corner of the dock is connected to the right anchor, and the right corner of the dock is connected to the left anchor. For a larger dock or a shaped dock with more corners, use more anchors. Leave the chains slack-you still want your dock to float up and down. You just don’t want it to float away.