Just to get you fired up, in such a circumstance, consider protesting under Rule 2. I think you could make a very good argument that such tactics are contrary to the principle of fair sailing. If I were on a jury in such a circumstance, I'd be very sympathetic to a claim under rule 2 or rule 41.
Alternatively, if you don't want to play the sportsmanship card, you could protest under rule 42 "Propulsion". Pulling a boat along the shoreline through the surf is not "using only the wind and water". Sailing instructions may, in stated circumstances, permit other methods of propulsion (such as assistance from shore crew for beaching), provided the boat does not gain a significant advantage in the race. See RRS 42.3(i).
