I have the old style PA seat. It was a bit too low and made getting to my feet almost impossible without going on my knees first then standing. As well it is in the way of the door that covers the raised tackle hatch. So I took the seat out. Here is a word to the wise for all with the old seat. The holdown nuts are just some inserts in a plastic piece with a built in tightening feature on top. First off the things are hard to reach and very close to the seat. Second is that the inserts essentially have a thread on the external portion to catch the plastic and hold in place. One side came right out. The other side was pretty stuck. The seat has not been out of the kayak in two years, so the brass insert on the stainless stud was corroded. I was able to get a pliers on the knob and as I turned it I discovered those threadlike features on the outside of the insert were cut such that instead of tightening as I attempted to loosen, they just screwed the insert out of the plastic. Now I had a stuck insert buried inside an aluminum tube with no way to get to it. I happened to have a piece of aluminum tubing and I experimented with drills in 1/64 increments until I found a very tight fit over the insert. With a long stiff blade and a small sledge I managed to drive the tube over the insert. Now with a pry bar I could hold down the tube as I turned it with the pliers. The insert is just barely bigger than the hole in the aluminum tube and the combination of down pressure along with the threadlike feature on the outside of the insert not only loosened the inner thread, it drove the insert through the aluminum tube. I got the seat off. So my advice is to do regular maintenance on that set of threads with some good anticorrosion grease.
I made a riser by using six pieces of 1 inch square aluminum tubing I had on hand. Drilled it to fit the spacing of the fasteners that hold the seat to the removable frame. Then stacked them log cabin style to make a total rise of three inches between the original removable frame and the seat base. Screwed it all together and then reinstalled the seat after seating the insert in the plastic again. Dry land tested it and now I can just tuck my feet close to the seat and stand right up. I also took the opportunity to move the seat back one inch and that gave much more clearance for the lid on the tackle box.
Hobie PA14 with a mod or twoSome random Modification Pictures