For the boat, I have a 10' x 10' boat lift that weighs 450-lbs and has never-ever been moved by the wave action, and is basically what holds my antique aluminum dock in its' spot, against the large incoming waves and weekend wakes. So's a new lightweight all aluminum dock with take-out deck pieces that simply sits on the sandy bottom will work. It will support a 100-lb canoe or something like a kayak that's dragged onto it.
I use a 5-gal pvc bucket loaded with concrete, that weighs about 250-lbs as a dead weight, on the dock, down the end, to help keep it from moving with the waves .... and it all works ..... totally perfect.
The weekend waves here are big, bad, and constant ..... so's most everyone has a boat lift. I like the big waves for kayak, row boat, sup, and swimming.
www.bmp-inc.com/ ..... located in up-state New York ..... worth a look-see? "The easiest aluminum docks at the lowest prices" ..... sounds like my last girl friend! ...
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https://www.youtube.com/watch?v=RWqMKcG855g