Scale 1:100. A plan showing details of girders and arrangement of frames in the double bottom of the Sidonia (1961), a cargo vessel. The plan is signed by 'M. A. van Vliet', stamped 'C. Van Der Giessen & Zonen's Scheepswerven N. V., Krimpen A. D. Ijssel, Holland' and is dated 28 March 1960.

There are also subsequent approval dates from the owners and Lloyds, detailed as follows:
Anchor Line: 7 April 1960
Lloyds Register: 2 April 1960
Both: 7 May 1960