Safe Hatch Locks, The “Shadow Locking System”
June 1, 2009 by captbbrucato
Among the many things to deal with these days in the new age is securing sensitive and critical areas of the vessel from unauthorized access from the outside. Doing so can sometimes put the crew at risk in an emergency of the combustible sort. Here’s a simple but elegant solution that has been put in use on my vessel. The “Shadow Lock” system designed by Chief Engineer Gordon Oliver is an effective locking system that will defeat quick unauthorized access when engaged. It can be “unlocked” with the flick of a wrist in mere seconds and drop out of the way to allow escape as necessary.
The pictures explain the system better than words, check it out, click on the thumbnails to enlarge.
The inner sleeve is 1" pipe, the outer sleeve has an I.D. of 1 1/4 ". The set screw is 3/8" with a tab tack welded to the top. The outer sleeve is drilled and threaded to accept the set screw. Note the cut-out. Align this to capture the opposite dog and slide the outer sleeve into place
The left end of the device (without the cut-out) has a small nub tacked on to prevent the outer sleeve from sliding off the end. Once in position, tighten the set screw. The device is invisible from the outside and it will take a rather noisy effort to defeat. When not in use it can be stored on an open dog.
Locked, it's that simple.