An incomplete wooden staff and four vanes. The vanes are in two parts and are held together by brass pins. The beginnings of the scales are marked ‘al’ for altitude, and ‘co’, for complement, the zenith distance. The vanes are not fitted with clamping screws. The three longest vanes are stamped ‘90’, ‘30’ and ‘10’ for use with the respective scales, which is consistent with the English naming of vanes.The fourth vane has no markings, suggesting that either one or three of the vanes belonged to a different staff.

The scales are from 90° to 40° (side one); from 90° to 25° (side two); from 90° to 15° (side three) and from 90° to 10° (side four), this is vice versa for the zenith distance. The maximum reading accuracy is 10 arcminutes for each side.

This cross-staff was recovered from the wreck of the Stirling Castle, which went aground on the Goodwin Sands off the Kent coast during the Great Storm of 1703. The instrument was found in a chest on the orlop deck in the after part of the vessel. The missing sections have subsequently been reconstructed.