Charter instruments
I remember a recent charter circumnavigating Shetland aboard a yacht which, we later discovered, had enjoyed the ‘benefit’ of a replacement depth display before we came aboard. Like most charterers, I check the offset with the owner; does the instrument show depth at the waterline or under the bottom of the keel? And, if the latter, is there the usual charter 0.5m ‘grace’? On this occasion, the answer was ‘the bottom of the keel, with an extra 0.5m’. We were sailing in company, and my fellow skipper duly told me he was bemused that I always seemed to be able to anchor further inshore than him. On one occasion we rafted up beside the pier at Fair Isle’s North Haven; I assured him the depth was fine. He came alongside with his echosounder indicating no clearance whereas mine suggested a metre or so. Out came the plumb line; he was right, and I had been blissfully anchoring with a low water clearance of centimetres! I went into the display menu only to find that the installer had omitted to recalibrate the instrument – the offset was neither set for waterline nor keel bottom, but halfway between! I now carry a length of line with waterproof markings at every metre as a plumb line to check the calibration.