The carbon laminate door is hinged on on some large stainless knuckle hinges I machined up. It is operated by an electric ball screw jack through a double redundant, double acting reverse purchase tackle. A sliding hatch over the top runs on Harken dinghy ball traveller hardware and can be moved from one corner with one finger. The 9' RIB fits inside fully inflated with the 9 hp Yamaha mounted and ready to go. I am still working on a proper mini-trailer to simplify launching and retrieval of the dinghy. The lazarette is sealed from the interior by the rear crash bulkhead, and self draining to about 35 degrees heel. Underneath is a watertight compartment:

The most interesting machining done for it was the single point locking scheme. This is upside down, the piece underneath started as a standard Southco M1 flip-up-and-turn type of tang lock. I machined the body out of aluminum bronze with box way type sliders from 316 SS. These have a single tooth each which engage the scroll gear, also machined from aluminum bronze. The scroll gear has a machined hex hole which mates with the nuts on the shaft, turn the shaft and the scroll gear pushes the sliders out. They are tapped on the ends into which rods are fitted, these run in delrin guides hidden in the teak caprail and drive pins into the matching caprail on the fixed part of the transom. Flip the handle up, one turn, then flip back down and you are locked. There is a key lock integrated into the handle of the Southco part. It took a little thought to get this right, the sliders are at an angle less than 180 degrees apart to match the curve of the transom door, and the scrolls similarly offset. The single tooth profile has to accommodate the changing radius, and be set at a different angle for right hand and left hand. The round pin machined onto the end of the tooth drops into a hole through the scroll gear in the locked position when the handle is cammed closed, locking everything quite securely:

It all ends up pretty much hidden. You can see the latch in the middle of the hatch caprail, right next to the recessed Lopolight sternlight. Another issue was the wiring for the solar panels and sternlight. I used 'energy chain' of the type used on industrial machinery, made to guide wiring between moving machine parts. You can see that on the port side of the hatch opening. Kind of like a hollow bicycle chain, it flexes one direction but is stiff athartships, the wire runs through the middle of it and keeps everything tidy: