Page 92 - Green - Maritime Archaeology: A Technical Handbook. 2nd ed

Chapter 3: Search and Survey 71
Figure 3.29 A GIS of the Deepwater Graveyard showing the magnetic contour diagram shown in Figure 3.27 georeferenced on a chart of the area together with other data.
aluminum superstructure of the later Type 12 vessels built in the early 1970s such as the HMAS Swan and HMAS Torrens (Geoff Hewett, personal communication). So the tonnage represents a totally iron hull with 1% aluminum, whereas the later Type 12 had about 20% aluminum in the superstructure.
Using the Hall equation (Hall, 1966)
where
DM = nT W=t D=m
Ê Aˆ = length/breadth ratio Ë B¯
For HMAS Derwent
DM=A104 W B D3