It is in great shape. The normal wear and tear. Not sure about the exact age, I bought it is 2002 from a guy that bought it new.
Excellent seakayak great shape. This is a great play boat, fast and surfs well.
Length: 17' 11"
Waterline length (170 lbs. added) 16' 1"
Beam: 21.5"
Waterline beam (170 lbs. added) 19.5"
Cockpit size (inside): 32.5" x 15"
Depth at front of cockpit: 11.5"
Depth at rear of cockpit: 10"
Volume (filled with water): 14.0 cu.ft. (105 gal.)
Est. volume (if Sea Kayaker method used): 14.8 cu.ft (111 gal.)
It has plenty of room for expeditions.
https://paddling.com/reviews/product/mariner-kayaks-inc-mariner-ii-1-kayak/
http://www.marinerkayaks.com