It is warm and calm even though it is October. We motored up to the Tyne. No wind. Poor viz. But strangle also bright sun. A clear shadow on the compass let me do some calibration.
Tuesday, 13 October 2015
Checking the compass deviation using the Sun
Our Plastimo steering compas has a pointer to cast a shadow to check for compass deviation.
It is 11:35 UTC on 10/10/2015 and we are at around 54 deg 10 N 1 deg 10 W so the LHA of the sun is 178 deg. Variation is 3 deg W, so the compass bearing of the sun should be 181 deg and the shadow 001 deg. We can't read the compass to that accuracy but it looks about bang on. It is a pity Plastimo did not make a longer pointer. Repeating the exercise turning the boat around we can swing the compass and make a deviation card. Not however while the First Mate is passing a cup of soup up the companionway.
It is 11:35 UTC on 10/10/2015 and we are at around 54 deg 10 N 1 deg 10 W so the LHA of the sun is 178 deg. Variation is 3 deg W, so the compass bearing of the sun should be 181 deg and the shadow 001 deg. We can't read the compass to that accuracy but it looks about bang on. It is a pity Plastimo did not make a longer pointer. Repeating the exercise turning the boat around we can swing the compass and make a deviation card. Not however while the First Mate is passing a cup of soup up the companionway.
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