A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Murray Buckman
Date: 2022 Nov 29, 10:22 -0800
Frank, you wrote:
"Using his exact value of 4.5' for dip implies a height of eye of 21.5 feet using standard dip calculations or tables. Isn't that rather low for a big oil tanker?"
I wondered about that too.
I think your follow-on comment about using a lower deck is probably correct, though I get your point about even a suitable lower deck being higher that the dip correction implies.
Why use a lower deck? Perhaps to avoid the jokes from those on bridge as you take out your "obsolete" tools and proceed to take sights. Perhaps, if the celestial objects of interest appear on the leeward side of the ship, for a little shelter.