Hey, I think I figured out what we are looking at in that museum chart. Post # 4, Figure 148, the 'sailor's sword', is hinged. This was probably a sketch of a very large navaja 'knife', controversially believed to be carried by sailors and thus misidentified as a sailor's sword. I've had whole threads I've started and argued about concerning sailors carrying jack knives, but I won't digress right now (I just bought my first navaja and will post it soon with all the arguments pro and nay for sea use!
. Of course, it could be something else...