Drifting

Ah Winter..........the time of dreams and plans. I sit in our cozy cabin and reach for a pilot, mentally sailing across the sea and thinking about where to go in the spring. Where will Dark Tarn take us?

I don't have to drift very far before I am sidetracked by an old story.

Sailing South down the East Coast of Ireland you pass Arklow and Rosslare at this point I have promised Lynne we will cross back to Wales to visit Pembrokeshire.

So there we are, crossing St George's channel in my minds eye and suddenly I realise we have just crossed the Sumner line. Of course you can't actually see it, in fact it didn't exist until December 17 1837. Captain Sumner was on a voyage from South Carolina to Scotland. Not having a had a sun sight for a few days Captain Sumner was unsure of his position, however he knew he was in the vicinity of the cluster of islands and rocks off the south west corner of Wales known to the ancient Greeks as the headland of the seven perils. Suddenly the clouds parted and Captain Sumner was able to get one sight. He duly plotted this and he got a latitude fix. However he would need several more sights to establish his longitude. Pondering this he plotted the same fix by reducing the sight by 10 and 20 degrees from his estimated position. Lo and behold the sights formed a straight line. The Sumner line. The line intercepted the position of the Smalls light. Captain Sumner turned to follow the line and the light duly appeared on the bow a few hours later.

This is the basis of modern celestial navigation later refined by Marq St Hilaire, The line isn't actually a line, it's a part of a circle where the altitude of the celestial body is the same from everywhere on the circle. Imagine a room with a single lightbulb and visualise the cone of light it throws on the floor and if you walked around the light measuring the angle between the cone and the bulb the angle would remain the same, you get the basic idea.

There you go, simple idea, but crucially no one had thought of it before.

Unfortunately this story doesn't have a happy ending because our hero ended his days in an asylum.

However I for one salute you. It's a brilliant piece of abstract thinking, this particular area of sea I pride myself on knowing very well. A wonderful cauldron of tides, history, landscape, wildlife and welshness. I need to return and  as I do, I promise I will remember captain Sumner as we cross his invisible line.

Of course I will also remember a day when "Two Timer" was knocked down and rolled off the South Bishop light. But that's my history and another story..........