John,
you also raise an interesting issue;
Looking only at the nightime portion of HB162, it is clear that the Coast Guard is in support of the 25MPH limit, if not slower.
While all of the water skiing sites recommend a speed at or below 25MPH for recreational water skiing, the Coast Guard Auxiliary's "Safety Tips for Water Skiing" publication (
http://www.uscgboating.org/safety/metlife/water_ski.htm)
warns that "
Any boat traveling fast enough to tow a skier is traveling too fast to navigate safely at night."
Of course, there will be some on this forum who will figure out some angle for reasoning that even this clear warning does not apply to NH lakes, where the water is denser, skiers are faster, or statistics are not kept on boat speeds.
And I wonder why the CG would even bother to warn about night time speed anyway, since according to Director Barrett and some on this forum; "There is no correlation between speed and danger in a marine environment".