Re: Side Panel Construction
That's the standard. I've seen a few other good ideas too.
One is to use teak or a similar wood, attach planks to a frame horizontally with gaps between and use that for sides. It looks better than it sounds.
Also I've seen boats with the top cap trimmed, the edge of the fiberglass with a protector or channel on it, and the inside of the hull painted. Makes a small hull a bit bigger.
If you're skilled enough to do it, fiberglass panels with molded shelves are nice and low maintenance. It's a pretty flat shape, so it can make a good first fiberglass molding project.
But yeah, marine ply (or a good exterior grade) with covering is a nice standard way to go. Use stainless steel staples or a waterproof adhesive to hold the covering in place. Lots of threads here involving simple upholstery work. Don't forget a thin foam pad anywhere someone might lean, or use foam backed vinyl there... it makes a big difference in comfort and wear.
Erik