(1) "Serious bodily injury" means bodily injury which involves a substantial risk of death, serious permanent disfigurement, or protracted loss or impairment of the function of any part or organ of the body.

(2) A person is guilty of assault by watercraft if he or she operates any vessel:

(a) In a reckless manner, and this conduct is the proximate cause of serious bodily injury to another; or

(b) While under the influence of intoxicating liquor or any drug, as defined by RCW 79A.60.040, and this conduct is the proximate cause of serious bodily injury to another.

(3) When the injury is caused by a skier towed by a vessel, the operator of the vessel is not guilty of assault by watercraft.

(4) A violation of this section is punishable as a class B felony according to chapter 9A.20 RCW.