They're one of the best riding 20' boats ever made,
until someone screws up the CG by hanging a heavy 4-stroke motor 30" further aft on a bracket! That can be corrected by moving console, batteries and gas tank forward. If it tends to porpoise a lot, it's still stern heavy!
All SeaCrafts except the original Moesly 21 have fiberglass stringers.
Go here to learn all about SeaCraft boats!