It was put in effect in 1972. Lots of changes since then but that was first issue.I don't when the law came into effect, but the Coast Guard started requiring capacity plates on newly manufactured boats. Capacity was restricted based on some rather simple formulas, and are generally less than what people used to actually load in calm conditions. The capacity plates were established specifically to prevent overloading. For canoes and kayaks (and perhaps dinghies), capacity is established in pounds, not persons. Given that the old aviation standard of 160lbs per person no longer applies to most Americans, it's very easy to see how overloads continue.
Based strictly on carrying capacity, a canoe (or dinghy) with 450lb capacity can be overloaded with 2 large men. Or can carry 3 small women. Of course, seating them appropriately is another matter.
My 19ft Carolina Skiff has a capacity plate that states 8 people. But there's really only room for 6 to be seated (at best). And if it's just me with 2 heavies in the stern seats, the boat handles very poorly - the bow waves in the wind, and the boat is hard to get up on plane.
On the sailing side, going downwind in dinghies in a good breeze often meant parking my butt on the transom to stop the bow from digging in, especially when surfing in waves. Of course, a Hobie 16 is the ultimate pitch pole machine (yes, I have the t-shirt).
Fred W
My dinghy does not have a capacity plate because it's a sailing dinghy.
33 CFR 183, subpart C states:
Subpart C—Safe Loading
§ 183.31 Applicability.
This subpart applies to monohull boats less than 20 feet in length except sailboats, canoes, kayaks, and inflatable boats.
I imagine the West solid dinghy has a capacity plate.
On your 19 foot skiff I'm sure needs to be balanced - in my 8 foot dinghy it's absolutely imperative...
dj