San Francisco Waterfront History
The San Francisco Waterfront
The Social
Consequences of Industrial Modernization
Part One; "The Good Old Days"
By Herb Mills
Page 22
Since many a man had fallen from one deck to another while uncovering, there was strong insistence upon a "three-foot hatch space" rule, i.e., the men insisted upon having three feet of clear space between the cargo remaining on the deck and the hatch boards which were being removed. An insistence upon hatch space also reduced the chances of cargo falling upon the men from a deck above where they were working.
The operational circumstances encountered in the lower 'tween deck would be a variation of those which have been pictured for the shelter deck. So, also, would the subsequent uncovering and discharge of the "lower hold" be much like that just described.
On the other hand, the work of the winch drivers, who, from the weather deck (or above it) controlled the movement of the cargo hook and loads between the hold and the dock, became increasingly demanding as the holdmen descended into the vessel. On most vessels, the descent of the holdmen into the hatches aft of the midship house (superstructure) continued beyond the lower hold into an offshore and inshore "deep tank."