I would respectfully suggest that the most classic of all SeaCrafts were the Moesly boats that started it all, from 1961 to 1969, ie., the "21" and it's racing relatives, the 19' Bowrider, 15' Scampi, the 27' flybridge Sedan cruiser, and the 20 CC and Seafari models. See
Moesly SeaCraft web site for more info.
Potter built good solid boats after he bought out Moesly, but his designs were more evolutionary, rather than revolutionary, as Moesly's were at the time. The 18 and 23 were the only hulls Potter designed. The 18 appears to be just a 20 with a couple of feet cut off, while the 23 was loosely based on the 21. The 23 is a great riding boat, but my good friend that owned the 21' Unohu, which he ran hard for 27 years, making several Bahama crossings every year, many of them with 23's, claimed that every time the seas got over about 3-4', the 23's would have trouble staying up with him, and he didn't run that fast! His first 2 engines (he literally wore out at least 3-4 engines, and several outdrives and sets of heads!) were I-6 Mercruisers which cruised at about 18 mph (regardless of sea state, until it got up to 10-12', when he'd slow down to his min planning speed of 12 mph!). When he started running V-8's, cruise speed went up to 22-23 mph, and he'd hold that in seas up to about 6-8'. Not sure exactly what changes that Potter made to the hull in going from the 21 to the 23 other than more length and less freeboard, but the steps don't seem to be as deep on the 23 and it looks to have a little more deadrise on the outer panel, which might hurt low speed planning and maybe increase running angle, which could make for a harder ride in the 2-3' square waves (equal height and spacing! [img]/forum/images/graemlins/tongue.gif[/img]) that are common on the Little Bahama Bank.
From the many projects documented on this site, it looks like Potter changed the 20's from the 4 individual f/g stringers to 2 wider box stringers about 1973 or 74. The first gas crisis occured about then and the cost of gas and resin spiked, so maybe fewer stringers was a cost reduction measure, but the later boats seem to be just as solid as the earlier ones. There have been a couple of isolated cases of loose stringers documented on 23's, but with no apparent hull damage, so there is evidently so much glass in the basic hull layup that even a loose stringer is no big deal!
It also appears that the Tracker models started using plywood in the decks instead of balsa core, which made them significantly heavier, but certainly no less solid.
Having said all that, any boat built by humans is susceptible to the occasional production line screw-up (remember the "Friday-car" lemons that Detroit used to occasionally turn out?!), but the early SeaCraft designs were so robust that there was ample margin to accommodate the occasional quality lapse. With cost pressures being what they are today, I suspect few modern boats are as overbuilt as the SeaCrafts and probably the Bertrams from the 60's and 70's.