We owned a NP39 for six years. The worst weather we faced was 4-6 footers with an occasional 8 in Buzzards Bay, MA. We did not like it much but the boat didn't care. The chop there can be "square". Felt very safe.
Chartered a NP 43 out of La Conner for the month of July in 2018. We had great weather if a little cool so nothing challenging sea state wise which we liked.
Our present NP 45 seems better. We had 6-8' on the beam off the New Jersey with 24 Kn of wind also on the beam going from Cape May to Atlantic City. It was a miserable four hours but the boat handled it fine.
Like almost any vessel, the boat can take more than the crew.
Feel free to PM me.
North Pacific 45