09 Porthmadog harbour

Historic background

A deep-water harbour created as an unintended consequence of the building of the Cob in 1808-1813, which channelled the waters of the Glaslyn between Ynys y Towyn and the Green. The public quay (SH 5688 3838) dates from 1824, when the area came to be used for the transhipment of slate from river boats to ocean-going vessels instead of the exposed Ynys Cyngar to the east. Other harbours were constructed at Ynys y Tywyn and towards Borth y Gest until the 1870s, rail-served after the construction of the Ffestiniog Railway in 1836. A plan to develop Llyn Bach (SH 5720 3873 C - the area immediately upstream of the Britannia sluice bridge at SH 5707 3847), into a harbour in 1851 did not materialise.

As well as a major slate harbour, Porthmadog was also the site of a number of small shipyards which turned out the distinctive two-masted ‘Western Ocean Yachts’, and remained a stronghold of sail until the early twentieth century. The harbour saw little use from 1940 onwards, and since the 1960s has been used almost exclusively by pleasure vessels. Maisonettes were constructed on a number of the wharves in the late 1960s.
Key historic landscape characteristics

19th-century mineral harbour and ship-wrighting.

The harbour is made up of a series of stone-built quays making use of large blocks probably quarried in the immediate vicinity. A number of buildings associated with the harbour’s heyday survive, such as the sail loft, the seamen’s mission and the substantial houses, offices and warehouses at Pen Cei (Cornhill), most of which are now listed and described in detail in the listed building entries. A number of developments have added to the harbour landscape – the maisonettes near the station at SH 5706 3829 and 5708 3845 won a Civic Trust Award in the 1960s, and the Inland Revenue office on Ynys y Tywyn (SH 5722 3844). Some structures survive from the nineteenth century, such as the one remaining shed, which now houses the maritime museum, and Bron Guallt, built in 1895, the Oakeley Quarry shipping agent’s house and office (also listed).

Lewis’s Island (SH 5704 3791 C) is unusual in being formed entirely from ballast deposited by visiting ships; as such it forms a unique geological site, made up of stones from all parts of the world < back to the map
© Crown copyright. All rights reserved, Gwynedd Archaeological Trust, 100017916, 2005