Cork Harbour is a large navigable harbour, capable of accommodating the largest of vessels. As with all harbours it is not without it's hazards to navigation. Winter storms and poor visibility can increase these dangers. The large number of wreckings, strandings and other nautical diasters, over the centuries bear testement to this
Man-made aids to navigation were rudimentary, and early charts were notoriously inaccurate. Until the 19th Century, buoyage was sparse, with the Royal Navy marking a few well-known hazards such as the Harbour Rock. Roches point Lighthouse, at the harbour entrance was not built and lit until 1817.
Navigating the estuary of the River Lee to Cork City was fraught with danger, as the river meandered along large expanses of mudflats. For this reason, shipping to the city did not develop until improvements such as the navigation wall, dredging, and buoyage of the channel was completed