Ik not completely sure my self but I think you’re on the right track! I’m pretty sure it roughly means the petrol racing boats that whine and go really fast so disturb all the others and are dangerous!
Absolutely right! 👍 Internal Combustion; banned due to noise and oil / fuel pollution. Mainly the latter. Big electrics are also fast and dangerous. On the lake near me in Munich I have seen more than one completely destroy a scale boat by collision. 🤔 Cheers Doug
"The brain is not intended to store facts. It is for thinking, and for knowing where to find the facts !" Albert Einstein. 😉 cheers Doug
Mark & Skipper your both spot on, i/c is short for internal Combustion, again it's the noise factor and speed, but with the improvement of electric motors, i.e brushless the latter isn't so much a factor. Recently my club at Ethrow Park, already i/c are banned, have had to put a speed restriction on boats sailing there, due to complaints from members and public, of some modelers using excessive speed and harassing local aquatic bird life.