Portmore, Inishtrahull, County Donegal, Ireland
Summary* Restrictions applyA good location with attentive navigation required for access.
Exposed today; forecast to be exposed on Sunday, Monday and Tuesday.
LWS draught5 metres (16.4 feet).
Today's local tide estimatesLW 03:06, HW 09:39
LW 15:26, HW 21:58
Now approaching Neaps
Swell todayDirection W, height 0.9 metres, period 9.3 seconds, significant wave height of 1.0 metres.
Local weather outlook
Haven position55° 26.020' N, 007° 13.880' W
This is the anchoring location in the cut at the north side of the Island.
What is the story here?The sizable uninhabited island of Inishtrahull resides approximately six miles northeast of Malin Head making it Ireland’s most northerly island. Portmore is a quay situated in a cut on the north side of the island. Three to four vessels may anchor in the inlet off the small quay and shallower draft vessels may come alongside.
Portmore is a good anchorage that offers protection from all winds except those between north by northeast and east. Holding however can be poor in the rocky inlet. Access requires careful navigation as the surrounding inlet is fringed with rocks and the area is subject to strong currents, tidal races and surge. Great caution should be exercised when approaching Portmore if a swell is running. Otherwise, it is more than manageable.
Not what you need?
Malin Harbour or Slievebane Bay - 5.1 miles SW
Lenan Bay - 15.4 miles SW
Crummie's Bay - 17.6 miles SW
Dunree Bay - 18 miles SW
Tremone Bay - 11.1 miles SSE
Kinnagoe Bay - 12.9 miles SE
Portkill - 15.5 miles SE
Portnocker - 16 miles SE
Why visit here?Inishtrahull’s name is derived from Irish, Inis Trá Thuathail that, when heard pronounced by Gaelic speakers from west Donegal, is pronounced almost identical. The Gaelic means "The island with the strand on the opposite side". The only safe side to land on the island is here on the northern side, at Potamore, not the side facing the mainland exposed to the western approaches and open Atlantic; hence the island's name is derived from a landing description for boatmen.
It is therefore fitting that his is the most northerly berth in Ireland, with the country’s most northerly landfall in close proximity. In the case of the landfall, and if we leave aside the internationally disputed Rockall, the title of the most northerly part of Ireland is the sea stack ‘Tor Beg’. This is located a nautical mile to the northwest of Portmore across Tor Sound. Landing on Tor Beg, amidst a group of isolated rocky islets, is only achievable from a dingy in calm conditions by approaching the stacks’ less steep and more sheltered southern side. Likewise ‘Tor More’, the craggy thirty five metre and high most substantial stack of the group, can take a dingy landing upon the rocky shelves beneath its less precipitous northern side. Neither of these stacks offer any anchoring possibility and so Inishtrahull’s Portmore is Ireland’s most northerly anchorage.
Unlike the Tor’s the island of Inishtrahull is sizeable; 1.5 km east to west, with a land area of 0.34 square kilometres or approximately 80 acres. With high hills on the west and eastern ends joined by a low flat piece of ground the island could be described as hourglass shaped. It is formed from 1,780 million years old metamorphic rock called Lewisian Gneiss - pronounced nice - that is the oldest rock in Ireland. Indeed the rock in Inishtrahull is so old and so dissimilar to the nearby mainland’s deep basement rocks that is believed not to be part of Ireland at all. Rather Inishtrahull and the off-lying Tor Rocks, along with the islands of Islay and Colonsay, in the Scottish Hebrides, are believed to be a section that broke off the southern tip of Greenland during the Palaeoproterozoic Age. This travelled 1,300 km to anchor off the Donegal and Scottish coastlines via the process of continental drift. Those that set foot on Inishtrahull are on very old ground: rock that is almost two billion years old.
The island is uninhabited today but a short stroll ashore will clearly show that was not always the case. It is thought that early Christian era monks had a monastic settlement here but no evidence of this are to be found today. However the ruins of a community that resided here until the 1920s can be seen in the low flat stretch of ground at the centre of the island. Here an abandoned village that hosted a community of at least six families, including cottages, lazy beds, school and graveyard can be visited. The island was largely Gaelic speaking according to the 1901 census, apart from outsiders who worked the lighthouse and their families.
The last families to live on Inishtrahull earned a livelihood by supporting the ‘Irish Lights’ with a boat service plus small boat inshore fishing along with herring fishing during the season. This came to an end in 1928 when an en-bloc evacuation to the mainland took place. Lighthouse keepers continued to stay in residence until 1987. Then on April 30th the station became unmanned and so Inishtrahull’s last inhabiting humans departed.
Inishtrahull’s commanding lighthouse is the most northern Irish lighthouse. Situated on the western side of the island it is a reinforced concrete structure that includes an accommodation block and a slim white 23 metres tall tower to the balcony, plus a further 5.7 metre tall lantern. Flashing white 3 times every 20 seconds it is dominating feature of the island. Coupled with the lighthouse on Tory Island they form the two main landfall lights for Atlantic shipping rounding the north coast of Ireland. But this lighthouse was not the original Inishtrahull lighthouse as it only entered service in October 1958. Prior to that the first and original lighthouse was situated at the east end of the island. This was established in March 1813 to support Royal Navy ships using Loughs Swilly and Foyle. It was discontinued in October 1958 to make way for the new structure and its substantial ruins can be visited today. The stub of the original 12.8 meter tower still stands along with derelict living quarters plus other detritus such as fuel tank, steels, cogs, and old bits of machinery.
Today, except for visiting lighthouse personnel and the occasional passing boatman, the island is left to the waters and the wild. Owned by the Commissioners of Irish Lights it has been designated a Nature reserve by the National Parks and Wildlife Service. Being a remote island in a pivotal position, with a unique 90 metre deep sound adjacent to its southern side plus a rocky shallows to its north and fast running currents it supports a host of wildlife. Basking Shark, cetaceans and sunfish can be seen in the Sound in large numbers during the summer months and seals abound. A small heard of sika deer are also on the island but they are so shy and fleet-of- foot that is unlikely a small party from a boat would ever catch sought of them whilst ashore. The island attracts many unusual birds including, Purple Sandpiper, Turnstone, Oystercatcher, Barnacle Goose, Peregrine, Arctic Tern, plus a significant breeding Shag and Eider population. As such particular care is requested by visitors during the breeding bird period from May through to July.
Inishtrahull is a unique experience with an exceptionally good anchorage in Portmore. With complex tides in an area that very quickly produce standing waves with the least provocation, it is not a location that lends itself to a forward calendar entry. But if passing this corner of Ireland with an auspicious weather window where conditions invite, this very special and enchanting island is a must visit for the cruising boatman.
How to get in?A western approach from Malin Head to Lough Foyle will find a rugged Atlantic coastline. Malin Head, the northern most point of Ireland, is a low 70 metre high rounded hill with a square derelict concrete tower on top. The shoreline here is bold, jagged and fringed by outlying rocks that are steep-to and always visible. With the exception of Scars Rocks, lying about 400 metres west of the headland and always visible, there are no off-lying obstructions. A berth of 300 metres or more clears all dangers here but it gets more challenging once Malin Head is rounded.
Vessels approach from the mainland immediately south will find The Garvan Isles reside to the east of Malin Head and to the north of Slievebane Bay where the separately covered Malin Harbour resides. These are a collection of barren islands ranging from 15 to 22 metres in height and are surrounded by sunken rocks and shoals and they can be passed a mile to the starboard.
Vessels approaching from the east will find open water all the way to Inishtrahull. Those taking an offshore approach will find Inishowen Head provides the principal landmark. On closer approaches the bluff headland of Glengad Head will be seen with a remarkable hill near its extremity. From here it is best to head out directly to Inishtrahull eastern point a distance of six miles.
Inishtrahull is situated three miles northwest of the outermost Garvan Isle across the sound. It is nearly a mile long and is made up of two rounded hills joined by a stretch of low ground with a lighthouse at its western end.
Inishtrahull Lighthouse - Fl(3)15s 59m19M position: 55° 55 25.864’N, 007° 14.628’W
Portmore is set into a small inlet on the north side of the island. Boats closing on Inishtrahull from the west should approach the island through the sound and come south of the island. The off-lying ‘Blind Rocks’ shoal patch extending 300 metres north of Inishtrahull make it dangerous to come around the north side of the island. Once round the eastern point be prepared for a whirlpool that gets ferocious in springs. Search out the conspicuous red crane tripod on the quay and prepare for a final approach into the cut.
From the Portmore Initial Fix is half a mile out from a conspicuous red crane tripod situated on the Portmore quay and a bearing of 227°(T) set upon the crane from the initial fix will lead into the inlet and quay. The final metres will require eyeball navigation to pass the skirting rocks on either side of the inlet.
Deeper draft vessels can anchor in the mouth of the inlet where 5 metres will be found and space for three to four vessels will be found. Please be careful with swing room so as not to allow the vessel onto the ledges on either side of the bay. Discussions are currently taking place with regard to the merit of placing moorings here so do not be surprised to find visitor moorings in this location.
Vessels with a shallower draft can venture in closer into the rocky rectangular shaped box-like cut alongside the quay. This is 170 metres long and 25 metres wide with a 20 metre long quay on the south side made obvious by the red crane tripod. The quay has is a minimum of 1.5 metres available alongside and those who plan to berth here should do so at the southwest end to permit access to a pool alongside the quay.
This enclosed small pool is immediately adjacent to the quay and measures 18 metres by 24 metres with a LWS depth of 1.7 metres. The entrance to the pool is obstructed by a rock that dries to about 0.5 metres situated close north to the outer end of the quay. Hence the pool should be entered though the gap between the rock and the quay, by passing alongside the face of the quay. LWS access to the pool is therefore the 1.5 metres of water along the edge of the pier.
Those planning to stay in the pool overnight can avail themselves of a ringbolt to deal with the inner pools limited swing room. This is set into a rock opposite the inner, or south-western end, of the quay. By dropping the anchor in the middle of the pool and taking a stern line from the ringbolt the vessels movement can be safely confined.
What are the tides here?Today's local tide estimates are based on High Water Galway +0100
Today's Galway tides — High waters: 08:39, 20:58, Low waters: 02:06, 14:26
Today's Dover tides — High waters: 01:56, 14:17, Low waters: 09:32, 21:50 (From Tide Times)
We are now approaching the next tidal event that will be Neaps. View future tidal events in our lunar calendar
High Water Dover -0500 or approximately HW Galway +0100
Local HW is Dover –0500, Galway +0100
MHWS 3.3m MHWN 2.5m MLWN 1.6m MLWS 0.4m
Direction of stream Inishtrahull Sound
HW Dover start +0315, end -0115, ESE going, max speed 4 kn for 8 hours.
HW Dover start +0015, end +0315,WNW going, max speed 4 kn for 3 hours.
There is little slack at the start of the flood. However at the start of the ebb, from HW Dover -0115 to +0015, there is an hour and a quarter of slack water although this is reduced to half an hour in springs.
A rougher seaway tends to exist west of the Garvan Isles than to the east. If a choice of approach is available, bound inwards or out, keeping east of the Garvan Isles is most likely to be more comfortable.
Closer into Inishtrahull there is a circular eddy with a whirlpool during most of the west-northwest going tide or flood. It commences shortly after LW and that gets very strong in springs, from HW Dover +0100 to about +0430. The stream through Inishtrahull Sound on its south side runs at full strength to within 3 metres of the southern shore off Portachurry at the southwest corner and a 300 metre wide race stands here during all the ebb.
The above image represents the current tidal streams offshore of this haven. All times are in local time with red text indicating springs, blue indicating neaps and gray between tidal events. Click [+] to advance the estimate by an hour and click [ - ] to step back. Future tidal planning is best accomplished by using our manual tidal calculator . Do you need information on the tidal graphics?
What facilities are available?There are no facilities on Inishtrahull save for the small quay. There is a maintained well at Portmore but the water is stagnant and not great, and would need boiled. A much better well is to be found below the northern wall of the old school house.
What emergency contacts are there?Malin Head MRCC/CRS (Maritime Rescue Co-ordination Centre / Coastal Radio Station) VHF Channel 23 or 1677 kHz covers the west and northwest coasts of Ireland from Slyne Head to Inishowen Head. Donegal Bay VHF Ch 04, Clifden VHF Ch 26, Belmullet VHF Ch 83, Glen Head VHF Ch 24 provide relay stations. Coastguard Radio is always called on a working channel. Emergencies are worked on 16, 67 and working channel. Alternatively, or if ashore, phone 999 or 112 (free) and ask for ‘Marine Rescue’. Gardai (police), Fire and Rescue are also available on this number. Malin Head MRCC/CRS may be contacted directly on +353 77 70103
Other useful contacts in this area:
Londonderry Harbour Master: VHF Ch 16 and 14 ~ Call sign "Harbour Radio"
Phone: +44 28 71 861113; Mobile: +44 780 1032387
Malin Head Radio Station has a very positive attitude to interaction with leisure craft.
Any security concerns?Never an issue known to occur to a vessel in this isolate location.
What navigational resources are available for this area?British Admiralty 2811 ‘Sheep Haven to Lough Foyle including Inishtrahull’ scale of 37,500:1. Admiralty 2697 ‘Lough Swilly’ scale of 25,000:1 that includes Culdaff Bay at a scale of 10,000:1.
Imray chart C64 ‘Belfast Lough to Crinan and Islay’ and Chart C53 ‘Donegal Bay to Rathlin Island’ meet in this area. Discovery Ordinance Survey map No. 3 at a scale of 1:50,000 for inland details.
Ordnance Survey Ireland provide online maps which can be accessed here, alternatively OpenStreetMap provides local maps that include relief details plus walking and cycle routes for this locality.
With thanks to:Bill McCann, Londonderry Harbour Master and Gerry Sóna. Photography with thanks to Sean Venn, Arnold Price and Petre Broze.
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denis hutton wrote this review on Jul 15th 2013:
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