To avoid a very strong skinny guy that can sail with minimal weight in the light breeze and then tie on 50 pounds of water to his shoulders when it's breezy. To avoid the health (back and neck) risks associated with sailing this way all day? Reduction of mobility? The risk that someone might actually wear something heavier than water (i.e. they sink)?
Yeah, that is the reason for the monohull sailors -- they don't want them putting water bags on their backs and physically damaging themselves, hiking out with all that weight on their backs.
There are other ways to distribute weight on a body. Put weights on their ankles or wear a weight belt like scuba divers wear. Make a rule that the added weight on the body cannot be above the waist. Whatever.
In the case of catamarans, weight above the waist is not going to hurt sailors physically if the sailors are trapezing, because their back will be supported. But, regardless, it would help if the rules can say added weight to the crew must be at or below the waist.
That would discourage women crews from having breast enhancement surgery. <img src="http://www.catsailor.com/forums/images/graemlins/smirk.gif" alt="" />
