The tower displays several innovations introduced by its designer, James Walker. In particular, a stepped base to discourage the huge upsurges of waves. Another characteristic feature is austere vertical walls and the use of crenulated or battlemented stone parapets in preference to iron railings on the gallery.

Event and Historical Information:
Set in the narrow strait between Penmon Point and Ynys Seiriol (Puffin Island), the tower marks the north entrance to the Menai Strait and the passage between the two islands. It was built between 1835-38. Walker pioneered the use of a primitive sort of water-closet by providing a specially designed drain leading out at the base of the tower. A depiction on an historic chart dating to 1839 noted that is showed a red light at 61ft and that the fog warning was a bell. On the opposite side of the channel was a perch (see NPRN 518933). The tower has been unmanned for many years. The continuous light at Trwyn-du is now checked from the Holyhead Control Centre and was converted to solar power in 1993.

Sources include:
Hague, D, 1994, Lighthouses of Wales: Their Architecture and Archaeology, pg42-3
Historic Admiralty Chart 1170-A4, RCAHMW digital collections sourced from UK Hydrographic Office (published 1839)

Maritime Officer, RCAHMW, December 2008.