Ralph D. Stetson wrote in the December 1986 Mainsheet:
It should be noted that these wrenches can also be made of aluminum.
The problem with the stuffing box on the prop shaft is that it's hard to get to, the space around it is limited, and the adjusting nut is often seized by corrosion to the lock nut. Needless to say, special tools are required so that you don't tear up the rubber hose housing.
A machine shop can, using 1/8 to 1/4 inch cold rolled steel, cut the two (2) wrenches. The overall length is 8". The angle between the jaws is important, but does not need to be precise. Roughly 15 degrees is required. Lay out the design on light cardboard and cut it out. The dimension "X" on the sketch must be free to fit easily on the faces of the nuts. Squeeze the handles together to loosen.
On my boat, #298, Spi-Sea, the prop shaft and the rudder post have different size nuts, so I made a pair of wrenches for each.