What does your invention look like?
Have you done your homework? There are many devices on the market already, such as Turbolaunchers, Line managers, Line crawlers, line despensers, winders, along with easily tinkered up devices made out of PVC, wood, webbing, etc.
At least give us a hint on whether your invention would be left on the beach, carried along with the kiter, etc. Does it float? How much would it cost? Can it be used for anything else? Would a normal "beach comber" want to pick it up or steal it?
You don't need a "survey" to know that kiters would accept and buy a product that would be an asset to their kiting routine...so the only way to find out by a survey, if the product would sell, is to show us a picture, and give us a description of the procedure to use it, and then, ask us to rate the product as to acceptability judged by criteria, such as price, fashion, ease of use, danger, etc.