Here are the front of the cockpit section (the part that interfaces with the bow segment) for two Valley sea kayaks: the uppermost photo is a 2008 Valley Aquanaut LV and the bottom photo is a 2005 Valley Nordkapp. Both feature male interlocking pieces and rubber gaskets around the edge. What is different about the two kayaks is the bolt placement. The Aquanuat LV (top) has the two lower bolts placed to the sides, and not directly midline. The Nordkapp (bottom) has the bottom bolt placed right in the midline, at the v-bottom of the kayak. When I test paddled the Nordkapp, the lower bolt area allowed water to leak into the boat; the outside waterline was above the level of the lowest bolt. This would be less likely with the Aquanuat LV configuration.
I replaced the rubber washer (see prior post about rubber washers) in the lower bolt to see if this will provide for dryness. If not, then I will consider some form of modification to the outer rubber gasket. Should that also fail, leaving the lower bolt out (i.e. connecting with only three bolts instead of four) and filling the hole with removeable silicone would be mandatory.
Clip hull 3-piece kayaks, of course, have watertight sections as the clips are on the outside of the hull. Examples would be Rockpool and NDK boats. More on those later.