No pics, sorry. The boat is a CLC MillCreek, 13'.

Both my hatches are almost identical in size to the bulkheads. The bulkheads themselves have had their centers cut out, leaving about a 4" rim. The shape of the exact center cut out was smoothed and shaped to my esthetics, and not purely the hull shape. I.e., a rather rectangular opening. The hatches then set over or in front of the bulkhead frame, and look to the casual observer like a bulkhead panel. Much like how the access cover is removed from the circuit breaker panel in your house.

The bow hatch installs by setting the bottom down into a grove, and then using the two thumb wheel screws to pull the top up tight. The bottom grove was created by epoxying a strip of wood onto the bottom of the cockpit, leaving a gap between it and the bulkhead that is the same as the thickness of the hatch. With the hatch set into position, two holes were drilled at what looked like reasonable locations up on the top of the hatch going through the bulkhead. Threaded inserts were screwed into the bulkhead, and two knob headed screws are inserted through the hatch holes when it is in position and screwed down, drawing the hatch up tight.

The aft hatch is done similarly, but instead of a separate strip on the bottom of the cockpit the seat adjustment rails are used.

Both hatches are equipped with pretty drawer pulls to aid in handling them.

I had planned to gasket the hatches with closed cell neoprene tape. But I have not found a need for this to date. To be honest, I have not rolled my kayak, nor have I put it out in rough waters. But leaving it out in the rain and having it filled well over the bottom height of the bulkheads has not resulted in water intruding into either the bow or stern compartment. So the neoprene tape I bought still sits on the shelf. If I were to be planning an arctic expedition, I would probably install the tape.

You will need to do some trial fitting of the hatches, as there are invariably some interference problems and such. The corners of mine were rounded to avoid catching on things and to get away from fragile points. I made them a little smaller because big panels are awkward in a kayak cockpit and every little inch helps. Which meant I needed some guide tabs or ramps epoxied onto the hull to help me set the hatches in place quickly. I also had to make an odd looking scoop cut in the forward hatch because of the deck combing design. All not a problem to do, just a bit time consuming to do and make look nice.

The nice thing imo about using the thumb screws for locking the hatch down is that they are very positive locking, as opposed to stretching a strap across a panel. And I can always add more of them if I find a need due to panel warp or such. I have not found it a problem having the hatches secured with these knobbed screws. I have not lost one yet, extras are easily carried, and they are no slower to open then undoing straps and buckles, especially wet ones.

As for access, it's been no problem. My aft hatch is as accessable as can be, especially with the seat removed. The forward bulkhead is just ahead of the cockpit combing, and relatively easy to get to. Stuffing gear in hasn't been a problem at all.

As for hatches blowing off, I've had various hatches blow off of everything I can think of at one time or another. Be it a boat, aircraft, truck, etc. Far more common then complete hatch loss has been partial hatch dislodgement with the resulting leaks. Not a big deal in a car, but quite a big deal at sea in a kayak, especially in adverse conditions.