A proper fitting and manufactured life vest and helmet is critical when stretching you boat out to its triple digit limits. Any racing organization requires a Lifeline style racing vest and a Snell approved helmet. There are several different models available. Security Racing Product as well as Lifeline are the two largest racing vest manufacturers, but there are also several mainstream life vest manufacturers offering 100 mph impact life vests as well for much lower prices. A Race vest will set you back about 300-400 dollars, while a 100 mph impact vest will run you in the 60-80 dollar range.
The use of a "100mph lifevest" does not mean that a wearer would be less susceptible to traumatic injuries. As one boating safety specialist has pointed out-- following a 100 mph accident, hopefully, the 100mph life vest will still be fastened around the victim's battered, bruised and possibly dead body.