Methods for extracting kite energy by "reel-gen" inspired this method for wave-energy. The key element is a "Drag-Float", a sort of pontoon with a transverse board that causes high drag force against an anchor & a shore-based generator reel.

 

Surf-zones concentrate wave energy as each wave breaks in a fast moving surge. The return flow is also energetic. The prototype drag-float was made of strong commercial crabbing floats strung with a wood plank on a PVC tube. The power rope runs through the tube, fixed with stops. Varied line, pulley, & bungee rigging was tested off a small danforth anchor set "offshore". The drag-float hauled back & forth with high directional stability & lots of power (in shallows on the Pacific NW coast (KiteLab, Ilwaco, WA)).

 

This sort of DIY surf-energy looks useful for small to mid-scale renewable energy on many ocean coasts. Keeping generators ashore is a huge wave-power win. Small drag-boats are easily brought in for storms.

 

The attached JPGs show the rig set up at low-tide (01) & the drag-float resisting wave surge (02).