We had the same problem with yellow jackets getting inside the outside wall of our house. The pest control person injected a white powder substance that really solved the problem. Yes, the liquid spray is really "hot" stuff" and may very well do damage, you might want to try a very small test spot. Some of the sprays we have used also have an oily base which is very hard to remove, probably not good for sails and halyards. I think the pest control people have access to materials that we can't get, maybe better to just hire one and have done with it?
Thanks, that was my other concern, spray some of the stuff on the deck and turn it into an ice rink, while trying to get away from a swarm of wasps.