Crew Blog

Sailing by Numbers

04 February 2008

Maths, my gremlin. When I left school 10 plus years ago, armed with my GCSE in maths, I believed that I wouldn’t need much of what I’d been taught. I was wrong.

OK, so I got through Clipper training without consciously thinking about maths, but once boat preparation began, the numbers kicked in. Did we have enough metres of rope for the halyards? How many winch handles did we need? The wind and steering instruments had to be calibrated. And then there was the food…

The first leg was supposed to take 25 days with an extra 5 days of emergency rations per boat. A trip to the cash and carry with the victualler (who is in charge of buying enough food for each leg) had my gremlin jumping for joy. On arriving I was given a list of food to find and how many tins were required for each meal, what wasn’t on the list was that the tins available were larger and of varying sizes to a normal tin and my brain froze at the prospect of working out how many small tins went into one large tin. Ratios and we were still on land.

Since joining the boat, numbers have become a vital part of my daily life. Correspondence to Clipper race office and the ship’s log are done in UTC (GMT), while boat time is an imprecise affair based on the local time in our last port and changed only when sunset becomes too late or sunrise ridiculously early (before 3am at one point on Leg 3). The boat itself has a number to identify it in an emergency and the communications station has the race contact and emergency phone numbers posted clearly on the wall.

Beyond this there is maths galore, the latitude and longitude positions of our and other boats: position and distance; the speeds (boat speed and speed over ground which includes currents): differentials; watching the barometer rise and fall; using vectors; counting down the miles; monitoring the wind angle and assessing the difference between the true and apparent wind angles. I am amazed at other people’s mathematical skills on the boat; Keith came up with an equation containing sigma, sin and theta all divided by ‘n’ – I’m not at that level yet. Sometimes, just the act of remembering the numbers on the screen down below and relaying them to those on deck seems hard… I won’t even get into spherical geometry used to calculate great circle routes (the quickest route from origin port to destination port).

This brings me back to land and the fact that sailing forced me to rethink the importance of maths. Some need it for car design, embroidery or pigeon racing and even those who hated maths at school may need it to pursue their hobbies. To those people still at school, maybe one day you’ll need the maths you think is pointless – I did.

Gremlin, it’s time for the showdown.

Felicity McClarty