I'm curious - do boaters from out of state need licenses to operate on the lake? How about those rent-for-a-day PWC?
YES. It's not a license, it's a boater education certificate. NH does accept certificates from most other states, Coast Guard (Aux) administered test certificates and Power Squadron administered tests. Questions? Check with NH Marine Patrol to be sure if your certificate is accepted.
There is a TEMPORARY once in a lifetime 2 week certificate in NH for the rent-for-a-day places. A quick search of the archives provided the message with link (below).
As for the big waves. I appreciate your predicament and hope it never happens to you again. Although some boaters do not observe the 150' safe passage laws, that is not usually the majority of the wave problem. On a busy weekend the boat chop and cross chops carry far more than 150'.
It seems to get progressively worse year after year. More boats. Bigger boats. On a busy summer weekend you can sit off the Weirs with no boat passing within 500 feet of you and you will still have those monster waves to deal with. Our lake (and the use of our lake) is evolving. It is not the way it was 40 years ago.
Safe boating
The Commodore
Temp Cert info and link