99% of freshmen are considered novices. However, not all novices are freshmen. The "novice" category means any first-year rower, generally, regardless of age. "Freshmen" events are restricted to grade 9 students only.
Students with rowing experience.
Generally, both freshmen and novice events are open or "heavy" events. The rowers do not need to weigh in to meet a maximum weight limit. But if rowing for varsity events in the US:
Lightweight for boys, is between 150 and 155, depending on event and regatta.
US "Junior" events are open to all rowers, excluding Grade 12 & 13 ("PGs") oarsmen. Junior "B" is a classification for rowers under the age of 17 (US and CAN). Junior "A" is a classification for rowers between 17 and 19 (US and CAN).
US "Senior" events are open to all rowers occasionally, excluding Grade 13 ("PGs") oarsmen. Senior "B" is a classification for rowers between 19 and 21 (US and CAN). Senior "A"/Under 23 is a classification for rowers between 21 and 23 (US and CAN).
Lightweight for boys is either 66 kg or 72 kg, depending on event. "Junior" events are open to anyone who is a Junior B/under 17. "Senior" events are open to anyone who is an Junior A/under 19.
There are combination events: "senior lightweight" or "junior heavyweight." If there is no "lightweight" designation, it is implied that the event is open, or "heavy."
Weigh-ins occur on the morning of the event. Lightweight rowers usually get a stamp to indicate their certification. While rowers must meet a maximum weight for their class, coxswains (in some regattas) must meet a minimum weight (usually 110 lbs in US and 50 kg in CAN). If they are below this, they may have to carry sandbags.