Courses, bearings and GPSs

Most sea kayak navigation is done by identifying coastal features, checking on the map where you are in relation to them then paddling towards the one you want to get to. However, fog, night or tide might make things more difficult. I used to be a Luddite when it came to GPS units and it is fair to say that although I am a technophile, I was a late GPS adopter.



In this case I want to paddle to the channel to the south of Pabbay Beag from Stacanan Neideaclibh. The horizon is pretty featureless so I can take a grid bearing off the map, convert it to a magnetic bearing and the course is 89 degrees between the two points. I now paddle on a heading of 89 degrees and I should get there. But if there is a tide carrying me north from the course line, my bearing to my destination will change to say 92 degrees. I will have no way of knowing this unless I have calculated the speed and direction of the current before hand or if I have identified a more distant landmark behind my destination and the two move relative to one another (this is called using a transit). In this case there is no suitable transit landmarks.

This is where a GPS comes in. I set a waypoint in its memory for the place I want to get to by either; 1. entering a grid reference, 2. on a mapping GPS scrolling the pointer to the map position then pressing the MARK key or 3. if I was there earlier in the day, by pressing the MARK key when I was in the middle of the channel.

Next I press the FIND key and select the waypoint. The GPS then calculates the distance and course from your start location. Most GPS units have a GOTO page which displays a large arrow which points on a compass rose to the bearing from your current location to your destination. If you drift off course then the bearing changes. On simple GPS units the bearing pointer points to the top of the screen if you are on course. On more sophisticated units the bearing pointer will point to the destination if it is held flat. This is all pretty complicated to describe and in practice in rough water and if your eyesight is not very good, you will end up a long way off course before you detect the change in the bearing arrow.

In practice it is easier to monitor any change in the bearing as a number. On my Garmin GPSMap76cs I can set the bearing to the destination on a large type screen as a number. This is very easy to see especially for those elder paddlers whose close up vision is no longer what it was. If the tide carries me off course to the north, the bearing might Increase to 92 degrees. I now paddle more to the rIght and the bearing comes back to the course of 89 degrees. If I was carried off course to the south, the bearing might dEcrease to 86 degrees. I now paddle more to the lEft and the bearing comes back to the course of 89 degrees. In practice it is easy to keep within about one degree of the course on typical sea kayaking distances.

The GPS allows you to maintain a perfect ferry angle despite changing tidal flows. This is a function that map, compass, tide tables, chart and your brain would be unable to match. Off course it needs to be used sensibly. If you are crossing a channel and expect to be half way across at the turn of the tide, you may as well paddle straight across on a constant bearing and allow yourself to be carried down tide then up tide and these will cancel each other out and you will not waste time ferrying into the tide. Another point is that GPS units can be set to use various Norths such as grid and magnetic. I always set mine to magnetic so that if the GPS fails I can just switch straight back to the compass.

I explained all this to a friend who is very keen on skin on frame kayaks and Greenland paddles. He was rather dismissive of all this technology and wondered what was wrong with a good old compass. However, I am pretty sure the Inuit did not have compasses (not to mention aluminium frames and polymer skins).

PS in response to Cailean's reply.

In May I was fortunate enough to be part of a group that was led out to the Ecrehouse reef which lies 10 km off Jersey in the path of tidal currents that run up to 5 knots.

The leader was a very experienced local paddler who had been out to the reef countless times. He used local knowledge, his experience, compass, map, tide tables and tidal flow charts to take us out by the southerly route above. It was a safe crossing and allowed us to get carried down onto the Ecrehouse. If we had missed it we would have ended up going to England. However, we battled for 2 km more than we had to into a 3.5-5 knot current which was extremely tiring and a couple of paddlers in the group were very nearly exhausted by the crossing. The leader knew I had a GPS and asked how we were doing at the point we changed direction.

If we had done this crossing using the GPS then I would have set a waypoint about 1 km up tide of the Ecrehouse (at our final change of direction on the chart above) and we would have paddled straight to it.

I do think that being able to ferry at just the right angle using a GPS can conserve a groups' energy to leave a reserve for any unexpected tide or wind conditions they might meet later.

Here is a GPS track of a trip to Ghigha. On the way out it was flat calm and slack water. On the way back there was a 2 knot north flowing tide and a force 6 southerly wind. I used the GPS track not to navigate such a short crossing but to adjust the ferry angle. As you can see it was an efficient crossing in somewhat lively conditions!

Photography, is Photoshop a cheat?

This is a nice photo of a summer sunset off Loch Roag in Lewis. It is very much as I remember it but it is actually composed of 2 separate photos which were taken one after the other but with very different exposure settings. One was taken for the light in the foreground and the other was taken for the sunset. I joined them together later using Photoshop. If I had just set the camera to auto, the kayaker would have been a dark silhouette.

Simon Willis has recorded a Podcast with me talking about sea kayaking photography which should be published in the first week of December. The above photo is one that will appear on his website to accompany and illustrate the Podcast.

Some photographers do not like this type of photo, saying they look unnatural. What they really mean is they don't look like the photos they take! The human eye copes with a much greater range of light as it roves round a scene (with the iris altering its aperture as it goes) than a camera which takes a fixed exposure for the whole scene. Film and digital senors are also much less sensitive than the retina. Whatever, I like the technique and it's really just a development of dodging and burning when exposing a print in the darkroom. I did a lot of B+W photography before moving into transparencies but many photographers missed out the darkroom and have spent most of their careers using transparency film which allows for no post exposure manipulation. It was a highly skilled job getting the correct exposure on good old Kodachrome II transparency film with its 25 ASA speed and narrow exposure latitude. Those photographers take a great pride in getting exposure right first time and Photoshop must seem like the spawn of the Devil to them.

I think you can take photography far too seriously. As I said in the podcast to Simon, I am not a forensic photographer recording a crime scene. I am just trying to capture memories and memory is a fleeting and fickle thing.

Heading for Newfoundland.

The 22:00 hrs kayaks depart from Lewis for Newfoundland.

Wanted: Mink Men!

Mink on Bhacsaigh, Loch Roag.

For the attention of non vegan, unemployed sea kayakers! Scottish Natural Heritage seek persons with the following skills:

• Boat handling skills.
• Experience with firearms.
• Ability to walk over moorland between 8-20 kilometres per day.
• Good knowledge of the Western Isles.
• Experience of using working dogs.
  

Successful applicants will take part in the eradication of the mink from the Western Isles. Natives of North America, these relatives of the weasel escaped from fur farms in the 1960's and 70's. They have spread throughout the islands as they are strong swimmers and are ruthless predators of ground nesting birds. A programme of eradication was started in 2001.


Mink trap on Berneray.

I can proudly hold up my head and say that I have played a small but vital part in this public service. During 2004 we were camped on Boreray. In exchange for some fresh water, I did a favour for the island's sole resident Jerry. I transported a dead mink to North Uist so that he could claim his bounty. It was a very stinky minky.


Boreray, sea kayaking paradise.

Imagine you are at the edge of the sea on a day when it is difficult to say where the land ends and the sea begins and where the sea ends and the sky begins. Sea kayaking lets you explore these and your own boundaries and broadens your horizons. Sea kayaking is the new mountaineering.

Rocket Mail launched after 5 year countdown.

The film "Rocket Mail" was released today just 5 years after it was completed. It is based on the story of a German rocket scientist who came to the remote island of Scarp in the Outer Hebrides. In the 1930’s the first of a pair of twins was born on Scarp but there were complications and there was no phone to summon help. The second twin could not be delivered until the next day. The mother had to be transported across the Kyle of Scarp to Harris and then Stornoway in Lewis by boat, bus and car, some 72 kilometres distant.

Herr Zucher heard this story and set up a demonstration of rocket mail to allow the islanders to summon help in an emergency. Unfortunately the British would not let him use his own fuel and the rocket exploded scattering the charred remnants of the mail. Worse, the Nazi’s later imprisoned him as a British collaborator.



The BBC recreated the rocket launch for its superb series Coast.




The Sound of Scarp, across which the rocket was fired. Can sea kayaking get any better than this?

Return of the white tailed sea eagle.

This rather poor photo can only hint at the magnificence of the sight of a pair of white tailed sea eagles wheeling in the sky off the wild west coast of Harris in the Outer Hebrides. Sea eagles were persecuted in Scotland and became extinct in the 19th century. In 1975 birds from Scandinavia were reintroduced to Rum in the Inner Hebrides. They have slowly spread and this year there were 33 breeding pairs and 29 chicks were successfully fledged.

The west coast of Harris, what a place to paddle!

The Stones of Callanish

Not far from Uig on the Isle of Lewis lies mysterious Loch Roag. You can paddle your sea kayak to the shore at the edge of the moor of Callanish (Calanais). As you approach, you realise that the irregular skyline is composed of great stones raised on end.



You climb to the summit of the moor and you are dwarfed by the circles and avenues of the Callanish Stones which have stood here for over 4,000 years. No one knows what purpose lay behind the labour of our ancestors.



It is only when you get close to the stones that you realise their true beauty.

In the city I had an idea for a photograph. We would carry our kayaks up to the stones and stand them on end among them. Standing there on the moor, it seemed a crass thing to do and they remained on the beach. I am not sure whether our ancestors would have been amused.