I don't know about the 235 but my 97 245 was as stable as about any boat that size I've been on. Any wave or wake directly broad side will make any boat rock pretty badly. As Lou stated, learning to handle a boat can take some practice. There is speed, steering and trim to use in combination.
Can you have your friend with the Crownline explain how he handles the water will driving his boat and then go out with you and Tutor you on how to handle rough water?
My Crownline is a little better than my Four Winns in rough water but it is two feet longer and about 2 thousand pounds heavier so it should handle it better.
_________________
Terry
Current: 07 Crownline 255 CCR cuddy - 350 Mag MPI/B3 "Casi Cielo"
Previous:97 245 Sundowner 5.7GI/SX
Tow vehicle: 1986 GMC 2500 Camper Special 454/TH400
