(Updated, December 2015) An impression of a first-rate, depicted as a cross-section profile of a wooden model.

Although Phillips's main activity was as a military engineer, he was also familiar with ships, and in 1661 was appointed by the Duke of York as master gunner of the 'Portsmouth'. He therefore had both the interest and knowledge to create this cut-through section of an important ship, although the original purpose of the project is not known other than that a large engraving was a fairly early result. It may have been connected with the new gun-carriage that Phillips invented at the same time, in 1690, and with which all the guns of the 'Royal Sovereign' were ordered to be supplied. That said, the ship is not the 1690s 'Royal Sovereign', nor that of 1701, but one likely to have been built in the reign of Charles II since it has the crowned letter 'C' or 'CC' (possibly for Charles and Catherine of Braganza) forming the carved work of a stern gallery.

Previous speculation that it may be the 96-gun 'Charles' of 1668 has now been set aside following advice (December 2015) from Frank Fox as authority on warships of this period, who has suggested it is a first rate of smaller type and, while probably not a specific ship, one most closely representing the 'London' of 1670, though perhaps following her rebuild of 1679 from the later style of the figurehead. (Earlier ones has a carved whorl above the head of a thinner lion.)

Although this painting was acquired as attributed to Phillips (d. 1693), there is as yet no other evidence that he was a painter in oils. However, as an engineer he was a skilled draughtsman, including in watercolour, and often on a large scale. It is therefore less misleading, at least until proved otherwise, to consider this oil painting as more likely to be a copy of the large engraving of the same subject firmly attributed to him as 'By Capt Tho. Phillips second Engineer of England' (see PAI5017). This of course does not mean that he engraved the plate himself, but that he did the drawing on which it was based. It is also possible that whoever did this oil version had reference to the drawing, or at least a hand-coloured copy of the print, on which to base its colouration.