The Journal of Navigation: Volume 29 -

Saving Money by Cutting Corners
J. D. Proctor
Published online by Cambridge University Press:

01 October 1976, pp. 418-420
- Article
- - You have access
- PDF
- Export citation
This note assesses the savings in (time- and fuel-dependent) direct operating costs that are possible if every turning point on an airway is passed on the inside. Figure 1 shows a route with turning points at A, B and C. If a pilot follows the standard procedure of flying along AB until he is sure that he has passed B, his total track distance is (c + d + a + b).
To simplify the mathematics let us assume that he turns instead through half the required angle at a distance d before he reaches B and completes the turn after passing B abeam (and very close). His track distance will be (c + e + f). The difference in distance δ, representing the saving, is therefore (d + a + b) – (e + f).

The Navigator's Art. A. B. A. Hutson. 192 pp., 20 × 14 cm., Mills & Boon Ltd., London. £3·40.
W. E. May
Published online by Cambridge University Press:

23 November 2009, pp. 213-214
- Article
- - Get access
    
    Check if you have access via personal or institutional login
    
    Log in Register
- Export citation

Matthew Flinders and Ship Magnetism
W. F. J. Mörzer Bruyns
Published online by Cambridge University Press:

01 October 1976, p. 420
- Article
- - You have access
- PDF
- Export citation
Readers of Captain Cotter's paper under this title in the April 1976 issue of the Journal may be interested in some evidence that Dutch seamen in the seventeenth century were aware of this phenomenon of ship magnetism.
Abraham de Graaf in De seven Boecken van de Groote Zeevaert, published at Amsterdam in 1658, warns ships' officers taking bearings with the compass-that metal objects in their clothing can seriously deflect the compass, and mentions iron buttons and buckles. This was an important contemporary work on navigation and de Graaf was an examiner of officers of the Dutch East Indies Company from 1679 to 1714.

The Journal of Navigation