Wednesday, 1 February 2012

A Sextant, To An Extent

Woke up with a sore wrist today after throwing around too many t**** l***s yesterday. Just the day for playing with a sextant, then! This is a device used to take bearings of stars (usually the sun), and is what you see all the sailors using in movies about pirates in centuries gone by.

I had thought that its name derived from the fact that its angle can be up to 1/6th of a circle (I know you can get octants and quadrants) - but ours are actually 120 degrees, or a third, so who knows. Maybe "tritant" is too close to "trident" to be of comfort to seafarers? It comprises, among other bits and pieces, a telescope, a mirror, a "horizon glass" and the actual index arm which points to the scale of degrees. The basic premise is that you look at whichever star you want, then use the bit on the end of the index arm to move its reflection down to meet the horizon, and then see how many degrees you've moved it (this is *very* basic). There are all kinds of errors you need to take into account, and there's an almanac to consult to find out other things, and working out what you want to know is all very fiddly. But with practice - I couldn't get any other than theoretical today, as it was too cloudy to see the sun - I'm sure it'll be easy. I might head up to the bridge this evening to see if I can use it with night stars!

The rest of the day was spent greasing fire hydrants - a monthly job that is boring and hot. But necessary, I suppose. Certainly wouldn't want to get into a situation where there was a fire and the only thing preventing its extinction is the fact that the hydrant wheel is too stiff to turn...

We are due, again only theoretically, to arrive in Durban tomorrow evening. But there's word of a strike and it's very hard to get any kind of concrete information. One of the ABs was telling me that he was once at anchor outside a South African port for six days. Which would be good for studying, I suppose, but frustrating in a multitude of other ways. Still, a classmate of mine has been in dry dock on her ship for a while and is now heading out to stay at anchor for a month, so I'm grateful to have had the experience I've had so far!

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