NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Jeremy C
Date: 2022 Nov 30, 12:50 -0800
Ah, 21 ft is a bit low, even for a tanker bridge. I admit that I didn't do the math, just took my bridge's dip and cut in half, which is closer to the 40 ft mark.
In any case, a ladened tanker is quite low to the water. They regularly have waves rolling onto the main deck. Even on the bulker I was on, our freeboard was only 8-10 feet when we were down to the marks.
So, given about 20 feet, I expect he was either on the main deck or a deck or two above on the house. This might also explain the use of a hand compass rather than a repeater. As to the why, I suspect, and this is pure conjecture, that the vessel may have enclosed bridge wings. The only other option would be going to the flying bridge, which may be off-limits due to the EMF exposure from the RADAR and SATCOMs.
Jeremy