224466-Your 200 Merc must be pretty light to properly drain vs. a 509 Lb. 3.1L 200 Yamaha V-MAX. As I said before, your type of set-up with power and weight is not outrageously heavy, just overpowered. I have had 3 different motor set-ups on 2 different 18SF's.Your 86 18SF should be a 25 inch transom and draggin22s Potter era 18SF would be a 20 inch transom, especially to allow for the VMAX. So, your comment to go for it is bad advice and could put people in a dangerous situation. The transom cut out is too low and will quickly allow water to get in the splashwell. Do a search on the 18SF power on CSC and see the info that comes up since 2/2002.