View this artwork by appointment, at Tate Britain's Prints and Drawings Rooms
With the page turned vertically, here Turner describes various details of a ship’s masts, as identified by Finberg.1 The two largest drawings show top platforms. Each is supported by a grid of trestle trees, with upper and lower sections of the mast overlapping through their centres. These are fixed with caps above the platform in each sketch.2 Lower down, Turner lightly draws a long pair of horizontal lines in both instances to indicate the yard from which a sail would hang. The lower of these two drawings is inscribed ‘M Top S’ at left, presumably a notation that records the name and thus position of that mast within the architecture of the vessel. In this case, Turner probably refers either to the main topsail, or mizzen-topsail.
A third sketch of a thin mast at top right reiterates some of the features of the adjacent studies; a grid of trestle trees appears to cross the mast near the top, and the cap which joins the two overlapping sections of the structure is evident. There is no platform here, though, and the dimensions seem generally to be on a smaller scale. Although these sketches may represent disparate parts of various masts which engaged Turner’s interest, perhaps they equal a single structure, broken down into portions in order to contain the study on a single page of the sketchbook.