In October 2008 I did some cutting to address a decent centre hatch on the Swing....part 1 viewtopic.php?f=12&t=20207
...part 2 viewtopic.php?f=12&t=20209
Proved to very effective but on climbing out of the yak the lid flexed with my weight on it, and also when I pushed down with my right hand to exit, after 8 months use and thinking decided to make a straight line cut and add a heavier lid. Thought aluminium sheet but in the GC climate finally opted for marine ply, which is easier to work, strong, and a mate had an offcut to suit my needs [thanks Peter soon another yakker].
First step was to mark a new cutting line while the original plastic lid was in place, and decided on a cut to give 100<160mm width x 295mm long and measured are after it was all done because cutting from above with the jigsaw would leave a knife edge on the vertical long side of the hatch I initially cut about 5mm inside the line and then used a rasp horizontally shaving down to the line and leaving a flat top for the hatch seal rubber to press onto later...this took about 30 minutes to cut and rasp.
the hull has been sawn and the rasped and the marine ply has been cut and placed in position to check it will seal everything up OK
A lip was screwed under the D section of the new hatch and then drilled for screwing, and edges were sanded to a bevelled edge...the hatch was also bevelled along the edges and on the underside near the centre a piece of timber was glued and nailed in place to prevent any side play, and another block was but at the front end to prevent is sliding when I sat on top when leaving the boat.
Finally a cut a square of neoprene sheet to make a hinge, it was tacked under the front edge of the lid and later held in place on the front of the centre console with a piece of cutting board plastic, coming from under the lid no rain can enter the boat.
Final step was to apply about 5 wet coats of Epiglass Evidure 2 pot epoxy to seal the timber on all sides and then leave it all overnight to harden before the final assembly
the end result shows the hatch and hinge in place and under the hatch edge all around is a 3/8" hatch seal tape to seal the interior
the view when on the water with easy access, and having now sat on it, it is as solid as a rock when leaving the boat or sitting side saddle in the middle
a 2 litre milk bottle fits easily through the open hatch and is sitting in a couple of ice cream containers, also the hatch seal tape is visible in the shot under the lid...a couple of 4 litre tubs fit in easily or would be easy to fit one of sunshiner's mesh trays
This about completes the Swing with only a mast step to go in place through the drink holder when I get enthused again