NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: I wish I had thought to bring 'that' along with me...
From: Brad Morris
Date: 2017 Jan 24, 22:24 -0500
From: Brad Morris
Date: 2017 Jan 24, 22:24 -0500
Hello David
You wrote
Number 17 on your list – determining an accurate height of eye is ...
Once I tell you how to do this, you will undoubtedly smack your forehead.
Measure it directly. Use a string and a lead weight and dangle it over the side until it touches the water. Make a knot at eye height. Measure the string.
If you can't touch through water directly, use the string to take a series of incremental measurements.
You want to do this from both the port and starboard bridge wings, where you are likely to be taking your observations. Average the two readings. Try to do this just after the cargo is loaded, in port, while not underway.
When underway, the velocity of the ship will produce enough drag on the string to cause the weight to deflect backwards, giving an erroneous measurement (too long). It's possible underway, but with reduced accuracy. Use a monofilament line to reduce drag.
Brad
