Main topmast trestles and cross trees for the different classes of warship.
To scale, no scale mentioned. Plan showing a plan view of the main topmast trestle and crosstrees, an elevation of the main cap, and a plan of the main top, for the different classes of warship.
Initialled by William Symonds [Surveyor of the Navy, 1832-1848].
Initialled by William Symonds [Surveyor of the Navy, 1832-1848].