i have a 1993 glastron with a volvo 230 4 cylinder engine, the timing belt broke while cruising about 20 mph, luckily close to shore, i have the shop manual for the engine but i am worried that when the belt broke the pistons might have hit the valves, is this something that might have happened, also i would like to know the reason why the belt broke? the boat only has about 250 hours on it and the shop manual says to change the belt at 500 hours, i would appreciate any help.