Did some interesting research...
According to the FARS Encyclopedia, there were 38,642 fatal crashes in 2006.. that is for 245,628,000 registered vehicles... this gives us an incident rate of 1 death for every 6356.50329 vehicles
According to the 2006, the USCG Boating Statistics Report states there were 710 boating related deaths with 12,746,126 registered boats... for a rate of 5.6 deaths per boat... or one death for every 17952.2901 boats.
Now... I'd note that EVEN with the laws... enforcements... fines... etc., etc., etc... the number of deaths per boat (with it's lack of licensing and minimal enforcement) is still lower than the number of deaths per car...
Let's take a look at one other statistic... the boating death rate in 1991 was 8.3 per 100,000... the highest in the last 16 years... the death rate showed a marked decrease around 1996 and has held between 5.8 and 5.3 per 100,000 for the last 8 years... now let's map this phenomenon against gas prices... hummm...
I think it would suggest that the BEST way to reduce incidents on the water is to jack up the price of gas to an unaffordable level... people will still own boats but they won't be able to afford to run them... result...lower mortality and incident statistics and... THINK OF ALL THE MONEY THAT WOULD BRING IN FOR THE GOVERNMENT
(One could postulate that with increased "in dock" time the alcohol consumption rate would climb raising revenues even further AND as the police would hopefully catch on... they could set up sobriety check points at the entrance to marinas thereby improving local balance sheets as well...)
http://www.uscgboating.org/statistics/Boating_Statistics_2006.pdf
FARS Encyclopedia