Unless you plan extended trips or are particularly heavy or tall there's little reason to choose a very high volume kayak. Rocker and Rudders Rocker is the upward curve of the kayak's keel line over its length. Such a boat will turn easily but be difficult to paddle in a straight line. A boat without any rocker placed on the same floor will touch the floor over most of its length. It'll be difficult to turn but easy to paddle straight.
Tracking is more important than turning ability in touring and in sea kayaks.
To strike a balance between tracking and turning most sea kayaks are designed with a small amount, one to three inches, of rocker. Longer boats, boats with vee-shaped hulls, and boats with very fine ends can have more rocker without compromising tracking. Rocker improves a boat's handling in waves. In heavy winds and seas rudders are invaluable. They are also useful in doubles and in heavily loaded singles.