Why would anyone spend time and money trying to find a solution to such a simple task as securing a hatch? Builders of production boats ignore the problem. Professionals try to get away with as little as possible, amateurs do their best. In this case the leek proof hatches subdivide my boat into a number of waterproof compartments. The stored items gets protected from the elements and in the unlikely case of the hull getting holed they give flotation or contain the damage to the holed compartment.
It is true that a wing nut style bolt head or a simple small “T” handle welded to the Torx bolt head would make it easier to undo the bolts without any tools. I try to reduce the number of objects that can hurt me. That’s why I forgo that solution.
I do not think that I am likely to loose my Torx tool. 1976 I started to build a 19 feet aluminum boat. June 1980 I rounded Cape Horn with her. I divided the boat into several waterproof compartments bolting down the hatches more or less the same way. Obviously at that time there were no Torx bolts so I used hex heads. I had about 200 of those bolts on board. I still have quite a few of them M6 25 mm long. Not only do I have the bolts I also still have the tool. I used the same system on some of the hatches on Amphibie-Bris 89 sailing to Newfoundland and on Yrvind.com 2011 sailing to Martinique still the with the same tool. Torx tools are not cumbersome I will bring a score.

Foto showing the tool I used on my voyages since 1978. A bit rusty after the Martinique voyage but still functional.

Will the screws fail due to metal fatigue? I do not think so. There are fore M8 screws to each hatch. M6 would be plenty, even M5. I am even sure four M4 would do the job. There is plenty of redundancy.
Over center latches are good but here the geometry is not suitable for them.
Knots have been suggested. Knots are good. I have used them in in the sleeping room below the bed. Those hatches do not need to bee waterproof because the whole room can be sealed off.
I have knurled the screws. Thus on fine days I need only to screw them down with my fingers. When the sea starts breaking I tighten them up.
Have you ever been surprised at what a difference a few drips of oil can make to a rusty tool? The bronze washer is there to reduce friction and it works like oil. Now if by turning the screw the threads on the washer will be damaged so that it get stuck there permanently? So what? The better.

Photo showing knurls and cut away threads near screw head. I will bring hundreds.

Photo showing hatches in bedroom secured by lashing.

The system consists of three “cleats” and a string. There are twelv compartments below the bed. The matrass is divided into three parts for easy acces.

To be continued…

Regards Yrvind.