When my S-I-L received her settlement she had witnesses that verified the driver had driven recklessly. The insurance company investigated and she won (it didn't go to court).
From Nevada statutes.
NRS 488.400 Operation of vessel or manipulation of water skis or surfboard recklessly or while intoxicated or under influence of controlled substance prohibited.
1. A person shall not operate any motorboat or vessel, or manipulate any water skis, surfboard or similar device in a reckless or negligent manner so as to endanger the life or property of any person.
2. A person shall not operate any motorboat or vessel, or manipulate any water skis, surfboard or similar device while intoxicated or under the influence of any controlled substance, unless in accordance with a lawfully issued prescription.
(Added to NRS by 1960, 480; A 1971, 2031; 1973, 8; 1985, 343; 1987, 1554; 1993, 2237; 1995, 1723)—(Substituted in revision for NRS 488.205)
Read below about "comparative negligence":
http://www.courttv.com/archive/legalcafe/lifestyle/risk/assumption_background.html
Nevada is a "comparative negligence" state. However, you would have to find the boat owner more than 50% at fault. Read below pertaining to Nevada:
http://www.leg.state.nv.us/68th/95bills/AB520.TXT (Then go to NRS 41.141)
This link of interest can be helpful for any state that wants to know their state's boating requirements:
www.boat-ed.com