G'Day Paddlewise, Spent some time last week rereading David Burch's fundamentals of navigation - focused on the section where he describes the Kamal which is a sort of sextant made from string and a piece of wood - the technique is apparently thousands of years old. Hunted around for a thousand year old piece of string and an old biro case to use as a stick. Marked it off in cm using the latest in hi tech waterproof CD marker pens and took to the ocean. Have to say it wasn't an unmitigated success - found it extremely difficult to hold the biro steady enough to measure off the degrees, even with the antiquated string between my teeth. The other method where you hold up fingers at arms length with each finger corresponding to a degree was much more successful. I've no idea why it was easier to measure finger widths than 1cm gradations on a pen. Three of us were able to measure distance off to within ten percent at 1, 2 and 3km from an 80 metre cliff face. Though the estimate was helped with some dead reckoning from timing our paddling at 1km per ten minutes. Wondered how much success others have had with these kinds of rule of thumb. All the best, PeterO *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Correction that should be one finger corresponding to two degrees. All the best, PeterO ------- Original Message ------- On 10/20/2008 11:38 AM wrote: G'Day Paddlewise, Spent some time last week rereading David Burch's fundamentals of navigation - focused on the section where he describes the Kamal which is a sort of sextant made from string and a piece of wood - the technique is apparently thousands of years old. Hunted around for a thousand year old piece of string and an old biro case to use as a stick. Marked it off in cm using the latest in hi tech waterproof CD marker pens and took to the ocean. Have to say it wasn't an unmitigated success - found it extremely difficult to hold the biro steady enough to measure off the degrees, even with the antiquated string between my teeth. The other method where you hold up fingers at arms length with each finger corresponding to a degree was much more successful. I've no idea why it was easier to measure finger widths than 1cm gradations on a pen. Three of us were able to measure distance off to within ten percent at 1, 2 and 3km from an 80 metre cliff face. Though the estimate was helped with some dead reckoning from timing our paddling at 1km per ten minutes. Wondered how much success others have had with these kinds of rule of thumb. All the best, PeterO *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
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