Charts, pilots, weather – Scotland, West of Ireland to Scillies

The cost of a portfolio of paper charts for the British Isles is enormous, so we ignored advice in magazine articles and pilot books to stock up on large scale charts and relied mainly on electronics. (See this link to earlier posts: electronic navigation ).

We have:

C-Map NW Europe – chartplotter.
Memory Map UK and Ireland – laptop.
Navionics UK and Holland, including Ireland – iPhone.
Antares, Bob Bradshaw’s ultra large scale inshore charts for West of Scotland – laptop. (We tried them out in some very tight little anchorages, and they seemed very accurate).

We used Imray paper charts covering the whole area, though pilot books can be a bit sniffy about them:

C66 Mallaig to Rubha Reidh and Outer Hebrides
C65 Crinan to Mallaig and Barra
C64 Belfast Lough to Loch Foyle and Crinan
C53 Donegal Bay to Rathlin Island
C54 Galway Bay to Donegal Bay
C56 Dingle Bay to Galway Bay
C56 Cork Harbour to Dingle Bay
C7 Falmouth to Scillies

Next is a list of the larger scale UKHO charts we had on board, a very small proportion of those available. They cover a handful of particularly tricky areas in the West of Ireland. 22 of the 60 or so charts for Ireland have been reissued lately because of a major survey effort by the Irish government (see this link to post on survey accuracy ). But many others rely on Victorian era surveys. To check this, study the source information on any UKHO charts you buy  – its absence on Memory Map raster charts is their main drawback. It is also puzzling why there is so little source information on Imray charts.

UKHO 1820 Aran Island to Roonah Head
2792 Plans on the NW Coast of Ireland (the only one we would have missed).
2707 Kingstown Bay to Cleggan Bay and Inishbofin to Inishturk
3339 Approaches to Galway Bay including the Aran Islands (not the same Aran as in 1820).

We also had an old UKHO folio for the Mull and Oban area on board, bought in 2007 for a previous cruise, and not corrected since. In practice, when we wanted large scale UKHO charts we used Memory Map on the laptop.
Finally, we took 2692, Western Approaches to St George’s Channel and Bristol Channel.

Almanacs
Reeds
Cruising Association almanac

We economised on pilot books in Scotland by using editions bought for a 2007 cruise there. Apparently the Lawrence pilots will no longer be updated and the Clyde Cruising Club will be the only source. In Ireland, the 2013 edition of the Irish Cruising Club’s Sailing Directions is essential because substantially revised and because it is one of the best pilot books we have seen, even commenting area by area on chart accuracy.

South and West Coasts of Ireland Sailing Directions, 2013, Norman Kean, Irish Cruising Club Publications.
East and North Coasts of Ireland, Sailing Directions, 2002, Irish Cruising Club.
The Isle of Mull and adjacent coasts, Martin Lawrence, Imray, 2008.
Clyde to Colonsay, Martin Lawrence, Imray, 2007.
Skye and NW Scotland, Martin Lawrence, Imray, 2002.

For the Scillies, we have to admit to using a pilot bought for a cruise in 1994 plus the Cruising Association almanac and Reeds, and the large scale UKHO charts on the laptop.

Other
Cruising Ireland, Balmforth and Kean, Irish Cruising Club Publications – an excellent read for planning.
Cruising Cork and Kerry, Graham Swanson, Imray

Weather on line
Apart from standard sources such as Navtex and coastguard broadcasts we used:
http://passageweather.com/ – they have an iPhone app for Grib files, includes swell
http://www.metoffice.gov.uk/weather/marine/  (no sailing app yet).
Met Eireann for Irish Sea area forecasts.
http://www.sail.ie/  has useful weather links

Wind Guru – download the iPhone app
WeatherPro – land forecasts for seaside towns – download the iPhone app.
http://www.myweather2.com/   – for Ireland forecasts.
For rainfall radar and very short-term forecasts – meteox.com

Marine survey accuracy

Data published by the International Hydrographic Organisation shows up a surprising fact: the UK and Ireland are below Turkey in the league table of survey quality by area of national waters. Spain, Portugal and France score much higher than the UK.

  

Source : selected countries  from an International Hydrographic Organisation table.

 % of area at depths from zero to 200 metres which has been adequately surveyed

% which requires re-survey at larger scale or to modern standards

% which has never been systematically surveyed

Mediterranean

 

 

 

Monaco

100

0

0

Spain

97

3

0

France

95

4

1

Gibraltar

95

5

0

Turkey

88

12

0

Slovenia

80

20

0

Italy

70

25

5

Croatia

39

39

22

Greece

35

55

10

Morocco

30

0

70

Albania

25

45

30

Serbia Montenegro

0

100

0

Cyprus

0

100

0

 

Atlantic, NW Europe 

 

 

 

 

 

 

 

Portugal

100

0

0

Faeroes

100

0

0

Belgium

100

0

0

Germany, N Sea

96

4

0

Denmark

95

5

0

Canaries

95

5

0

Spain

94

6

0

France (Channel, North Sea)

89

0

11

France Atlantic

81

0

19

Norway

60

31

9

Azores

60

40

0

Netherlands

55

35

10

Iceland

52

48

0

UK

49

22

29

Ireland

26

74

0

 Greenland

25

25

50

Svalbard

10

1

89

Jan Mayen

0

0

100

 

Baltic

 

 

 

Germany

98

2

0

Finland

44

49

7

Poland

40

60

0

Sweden

25

74

1

Lithuania

16

84

0

Estonia

13

87

0

 

 

 

Checked January 2013

 There is one obvious reason why the UK’s position is relatively low; with a much larger area of shallow continental shelf, the British Isles has proportionately a far bigger survey to do than a country such as Turkey, where depths in many places reach 200 metres relatively close to shore.

Even so, it is widely known that there are cruising areas off the Turkish coast where chart accuracy is poor. Rod Heikell’s pilot warns that they can be out be by up to 2 minutes of longitude, considerably more than the warnings for anywhere on the British and Irish coasts.

 UKHO chart Q 6090 looks more deeply into the situation in the UK and Northern Ireland. It colour codes areas of the seabed by survey quality.  In the January 2013 edition, large parts of the coast of the Scottish mainland, Hebrides and northern islands, Wales, the Channel Islands, Lancashire and Northern Ireland are still marked as surveyed by leadline, or unsurveyed.

Follow this link to see UKHO chart Q6090

In an earlier 2006 version published in the AIB report on the Octopus (see Orkney Roulette page), the entire coast of  Ireland was marked as leadline surveyed. The republic’s coast has been left out of the latest Q6090, but the Irish government has now produced its own version of the chart, which shows a very large surveying effort since 2006.

Link to Ireland survey coverage chart

Interactive chart with local detail of Irish surveys

One result of the new surveys is that there have been new editions of 22 of the 60 or so admiralty charts for Irish waters since 2009, according to the Irish Cruising Club.

For practical decisions during a cruise, we have to rely on what electronic and paper chart publishers tell us about the underlying quality of their products, backed up, of course, by pilot book advice. This information can be pretty patchy. For example:

  • UKHO charts   have source data chartlets, a benchmark for quality.
  • Imray charts have no source data.  Some Imray charts do have general warnings on chart accuracy, eg for the Ionian and Turkey, where recent editions have quantified errors in the area as up to one minute and half a minute of longitude respectively.
  • Pilot books vary on the issue: Heikell has general warnings in his introductions of much larger errors in Greece and Turkey, of 1.5 minutes and 2 minutes longitude maximum respectively, but that covers a vast area.    
  • The Irish Cruising Club pilot’s latest edition for the West and South coasts of Ireland has gone much further, with localised chart accuracy information for different chapters, a good benchmark to aim for.  
  • Some other pilot books I have checked recently  do not seem to mention the accuracy issue at all, even where they cover cruising grounds which the tables above show have known  chart quality issues (for example parts of the Adriatic).
  • Many leisure electronic charts lack information on source data or other indications of underlying survey quality. They also lack last correction dates, and there is no detail of how comprehensive the updating is. Memory Map does reproduce source data diagrams on its raster charts but not edition dates, even though it is not hard to find UKHO charts for sale now whose most recent edition was three decades ago, for example on the West of Ireland.
  • To find comprehensive source information on an electronic  chart, you have to move to those used in Electronic Chart Display and Information Systems on ships, a different world,  where vessels equipped to a high enough standard are now allowed to dispense with paper charts altogether.

In preparation: articles on GPS accuracy and on what makes leisure charts unsafe compared with those used in ECDIS systems.