PhD thesis Navigation on Wood

Promotor Karel Davids of the VU summarising the past seven years (picture J. van der Steen).
Figure 1: Promotor Karel Davids of the VU summarising the past seven years (picture J. van der Steen).
[See below to order a copy]

On 9 May 2018, I graduated on my research of instruments for celestial navigation at the Vrije Universiteit Amsterdam. I started this research some 17 years ago, when I wanted to know which instrument(s) were used prior to the invention of the octant. After having published several articles on the topic I was allowed to start my PhD research at the Vrije Universiteit in Amsterdam in 2012. Now my PhD thesis is ready and printed in a limited edition of 300 copies:

N. de Hilster, Navigation on Wood, Wooden Navigational Instruments 1590-1731: An analysis of early modern western instruments for celestial navigation, their origins, mathematical concepts and accuracies., (PhD thesis, Vrije Universiteit, Amsterdam, May 2018).

In my thesis I explore the relationship between the instruments, their common ancestors, their construction, and performance of instruments in the period from 1590 to 1731. It was in 1590 when the Englishman Thomas Hood created his cross-staff, the first staff type navigational instrument that used the shadow of an attached vane to cast a shadow on one of its scales. His method of shadow casting was soon improved by countryman Thomas Harriot. Although Harriot's way of shadow casting resulted in a great improvement in the quality of the observations, by almost an order of magnitude, both methods of shadow casting remained into use well into the nineteenth century. Examples of instruments using Hood's shadow casting method were the Davis quadrant and the cross-bow quadrant, while examples using Harriot's method were the hoekboog and demi-cross.

The PhD thesis is a hardcover and comes with dust cover.
Figure 2: The PhD thesis is a hardcover and comes with dust cover.
The thesis is printed in a limited edition of 300 copies, hardcover, linen backed, with full colour dust cover. It has 815 pages with 324 figures, 47 tables, eight appendices (with additional figures and tables), and four indexes. The first year after my graduation the thesis will be available in print only, after that year as a download through the university's web site as well. Currently only the cover, titlepage, table of contents, and summary are digitally available.

The thesis has been made possible thanks to the generous donations by the following funds:Ordering a copy of Navigation on Wood
A copy of my thesis can be ordered by clicking here.

Together the funds financed approximately half of the printing costs, by which the thesis is now available for a modest 25 euro. Shipping will add another 7 euro for the Netherlands, 13 euro for western Europe, 19 euro for the rest of Europe, 25 euro for the rest of the world.


As expected no work can be made without errors. This section lists the errors found so far:

- p.228, footnote 811: " from the Birr Castle collection" should read " from the Birr Castle collection"
- p.377, fig.193: "demi-cross" should read "demi-quadrant"
- p.449, fig.224: caption should read "Standard deviation per observer of the human perception experiment."
- p.615, footnote 1799: reference should be: S. Purchas, Purchas his Pilgrimes in Five Bookes, (London, 1625), f.1213r.
- p.716, item 217: "Birr Castle UK" should read "Birr Castle, Republic of Ireland"


My knowledge on the subject still expands and below I reserved some space for the things I found after the printing of my thesis and which I wish to share with the readers.

- p.49: here I state that "As far as we know no part nor the whole book was ever published in print...", but in August 2018 I acquired D.B Quinn, A.M. Quinn, 'The English New England Voyages 1602-1608', in: The Hakluyt Society, Series II, Vol. 161., (London, 1983), in which I found on pp.232-235 short sections of the preface (ff.6-9) and the introduction (ff.201-204) to 'The fifte booke concerning fortification'. On pp.236-241 Quinn and Quinn also show six facsimile reproductions of the 'foundations and bullwarkes' (ff. 264v, 247v, 248v, 249v, 250v and 251v). It has to be noted that the transcription by Quinn and Quinn is mixed up on several places. On page 233 the transcription of Waymouth's work suddenly continues with Quinn and Quinn's own writing (last sentence of the first paragraph, the section starting with "a further opportunity to attempt it..."). The second line on page 234 suddenly jumps (after "...not with standing") from line 19 of folio 203 (f.203:19) to f.7:17. Likewise at the fourth line from the bottom of page 234 the transcription jumps back from f.9:7 to f.203:19.

- p.518, n.1667: The number of casualties in the Shovel disaster is mentioned to be somewhere between 1600 and 2000. In a writing in issue 79 of the Observator of 3 December 1707 can be read that "... we had Advice from Portsmouth, of Sir Geo. Bing's [Sir George Byng, 1st Viscount Torrington, who was present during the disaster] Arrival with the melancholy News, That Sir Cloudsly Shovel, in the Association, a second Rate, of 680 Men, and 96 Guns, was cast away on the Rocks call'd, The Bishop and his Clerks, off of Scilly; that the St. George did also beat against the same Rocks; that the Eagle, a third Rate, of 400 Men, and 70 Guns; the Rumney, a fourth Rate, of 280 Men, and 54 Guns; and the Firebrand Fire-ship, of 45 Men, and 8 Guns, were also lost." The St. George escaped to safety, without any losses. Totalling the figures of the four lost ships we get to a loss of 1405 men, considerably less than the modern figure of 1600-2000, but still an impressive amount and a great tragedy.

pp. 661, 704-818: Some of the instruments listed in Appendix C - Davis Quadrants around the World have the indication "Charles Mollan" followed by an Ex... number in the Remarks column. These entries refer to the following work which accidentally was omitted from the bibliograph: Mollan, R.C., Irish National Inventory of Historic Scientific Instruments: Report, (Dublin, 1995).

If you have any questions and/or remarks please let me know.

Celestial Navigation Coastal Navigation Distance measurement
1580s Mariner's astrolabe 1590 Hood's cross-staff 1618 Demi-cross 1623 hoekboog 1660 spiegelboog 1661 Kronan cross-staff 1720 Hasebroek cross-staff 1734 Davis quadrant Early 19th c. ebony octant Late 19th c brass octant 1941 U.S. Navy quintant Hirado navigation set PhD thesis