A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Mike Freeman
Date: 2017 Apr 22, 10:01 -0700
I have just read that when taking a sight from a small yacht in a heavy ground swell (say 20 feet) you need to add half the height of the swell to your normal height of eye before entering the DIP tables. It makes the point that the only time you see a horizon is when you are on a crest so your sight will be taken from a crest. This would be OK if the visible horizon was the same level but surely the visible horizon is made up of crests only. No need to consider this factor in my opinion.