The 170/175 is an inshore boat although I have had mine out about 10 miles on a good day.
The older ones have a 12 degree dead rise so it will bang on some waves if you're taking them too fast. Like any boat, you have to learn what it can and can't do.
I've owned my '70/71 since 88 and I love it. It's big enough for 2 fishing (any more and it's like a 5th wheel on as car) but if you need to transport a few people (I think it is rated to 4-5 people) to a place to hang it'll handle that.