It is rare to find a Cornish harbour which faces southwest, directly into the prevailing winds, and Porthleven's development as a port was always hampered by its orientation. Doubtless, Porthleven would have remained a small fishing inlet to this day had not there been an overriding need, in the early nineteenth century, for a harbour of refuge along this forbidding lee shore to which ships could run in times of distress.

The construction of the harbour, which was completed in 1825, had been hugely problematical and, although a large drifter fleet was soon engaged in the mackerel and pilchard fisheries, Porthleven remained a dangerous and difficult harbour.Major improvements were carried out in the 1850s, after the port was taken over by Harvey & Co. of Hayle, and the handsome, massively-built harbour that we see today dates from this time.

Porthleven went on to be famed for its boatbuilding and shipowning, but it never fully overcame its original, intrinsic problem; you only have to visit the place during one of the frequent sou'westerly gales that beset Cornwall through the winter to see why.