"the build-it-yourself boat ramp. these kit’s have everything you need to build your own capacity boat ramp! capacity boat ramp, just add treated lumber (not included in kit). this basic kit is a simple and cost effective way to dock your watercraft." "the build-it-yourself boat ramp.. Measure the length of your boat trailer, from the tip of its tongue to its tail lights and multiply by two. this is how long your ramp must be; few boat ramps are longer than twice the length of a boat trailer. measure the width of your trailer.. I've built a launch ramp which i used to launch my 16' hobie, and i can modify the ramp to haul my 20' maryland crabbing skiff, which weighs probably 500 lbs. +, up to the top of the seawall. the problem that arises is what to do with the boat once i get it to the top.. Bui...