ATTACHING OR INSTALLING DOCK BOARDING STEPS
Steps vary in weight, in quiet water there is generally no problem they will sit against the dock.
But with modern ski boats throwing 3’ wakes, care should be taken to insure your steps don’t wash away in rough water. .

Sea Wall Aluminum Free Standing

3 Step - 38 lbs.
4 Step - 50 lbs.
5 Step - 64 lbs.
6 Step - N/A
Plastic Tread & Aluminum Frame

66 lbs.
71 lbs.
76 lbs.
81 lbs.
The all aluminum (Sea Wall steps) have a frame that rests on the lake bottom. A couple concrete blocks on the bottom frame is often enough to secure them.
  installing sea wall steps 
   
using blocks to help anchor steps Concrete blocks between the legs and the foot can help secure the plastic tread steps. These steps are heavier and a couple concrete blocks should hold them in place.
   
  sea wall steps standard mounting hardware bracket for seawall steps

Plastic tread steps come with a bracket for attaching them to a dock or sea wall.
Brackets are 37 1/2" center to center. Even if you have a free standing unit, with back legs. It’s not a bad idea to use the hardware. This bracket will secure your steps to the dock.
 
  common installation items for sea wall steps 
  Common hardware store plumbing items like pipe hanger or straps can also be used. 
   
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