OVERVIEW
The challenging Gascanane Sound is a channel that separates the southwest end of Sherkin Island from Cape Clear Island. It lies between Cooslahan Point, the eastern extremity of Cape Clear Island, and Illaunbrock, an islet off the southwest extremity of Sherkin Island. The Sound is about a mile wide and is divided into two channels by the Carrigmore and Gascanane Rocks.

The former Carrigmore Rocks are located about 800 metres northeast of Cooslahan Point and are a group of high rocks that dry to 6.1 metres and never cover. The latter, Gascanane Rock, lays nearly 180 metres west of the Carrigmore Group and dries to 1.8 metres but cover at half-flood.





The tides sweep through both channels, especially at Springs, with such velocity as to cause dangerous eddies and it should only be approached with a commanding breeze, a reliable back up engine plus good visibility and favourable tides. Expect broken water in brisk conditions.

The advantage of taking the cut is it avoids passing around the imposing three miles long, south-westward lying, Cape Clear Island. But if there is any doubt, head around the island. If the tide is unfavourable in Gascanane Sound the Baltimore Harbour north entrance route could provide a better cut, especially so for vessels already moored in Baltimore Harbour.


LISTED WAYPOINTS
The complete course is 0.82 miles from the waypoint 'East & West Channels Southern Approach' to 'East Channel Northern Approach' tending in a northerly direction (reciprocal southerly).





THE EASTERN PASSAGE
This passage is between Carrigmore reef and Illaunbrock and is the preferred of the two cuts as it is deep, has its rocks visible on both sides and, being almost a ⅓ of a mile wide, is the more generous of the two passes. Likewise, Illaunbrock, though foul to the north, is fairly steep on its southern and westerner sides.

Care is still needed with the currents whilst passing through the cut. When taking the eastern passage the vessel will be steering roughly north or south whilst the tidal flow is slightly crosswise running roughly northwest and southeast. Therefore a vessel passing northward will have the current setting onto the Carrigmore Rocks, awash, or when going southward on to Illaunbrock.

The key to using either of these cuts is to work the tide. The streams set strongly through the sound attaining a rate of 3kn during Springs causing eddies. The east-going stream set southeastward, and the west going stream sets northwestward. They begin at the following times:

• • The west going tide starts running northwestward at +0540 Dover, or at –0055 Cobh


• • The east-going tide starts running southeastward at -0030 Dover, or at +0520 Cobh.

Cross tides tend to can set a vessel onto the rocks in the eastern channel.

The waypoints are for guidance only as this cut centres on pilotage and should only be used in moderate conditions with good visibility. There is nearly always a groundswell entering the sound which can make the passage look threatening.

What is the best sailing time?

Sailing season is May to September, with June and July offering some of the best weather. Nevertheless, the incidence of gales in June and July are on average two days of winds each month of winds up to force seven. So you may be either held up or having a blast depending on your sailing preferences. Ireland is not subject to persistent fog statistically complete days of persistent fog occur less than once in a decade.

Are there any security concerns?

Never an issue known to have occurred sailing off the Irish coast.

With thanks to:

eOceanic & Burke Corbett.