A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Samuel L
Date: 2014 Dec 25, 03:56 -0800
Bowditch can be found here;
Here's the information you're looking for;
Bowditch Chapter 24, The Sailings, page 347 shows the procedure to obtain distance and initial bearing between 2 locations using HO 229.
Bowditch Chapter 22, Calculations and Conversions, page 332 gives the distance and initial bearing formula.
The man at the link below mentions a formula for calculating distances and bearings between 2 places on earth.