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+--- Thread: Small error in Chapman (/showthread.php?tid=183)
Small error in Chapman - Rumata - 03-21-2019
Gentlemen.
just found a small error in 1966 Chapman. But then found out it was corrected in 1974 ed. Just for info:
Concerning the usage of maneuvering board. page 430b in 1966 edition. It is an example how to calculate the direction and velocity of the true wind so as to determine whether you can lay the mark on the next tack and the best course you will be able to make to windward.
Without going into details, let's me just mentioned from that paragraph "...To solve for the new tack we mark the wind new apparent direction of 169 ( add 17 to 142) ( this is math wrong 142 +17=159) and then add 45 deg on which you wish to sail. This gives 204 the new course..." Wind is coming from 125 deg. The boat movement through the water caused the apparent wind to shift 17 deg counter-clockwise from its true direction.Then by mistake just added 17 deg twice.
Chapman 1974 ed. , page 452, corrects the error. 142+45= 187.
Am pretty sure you would not use the wrong approach taking by 1966 ed. Nothing for granted. Thank you.