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    Re: Wartime (WW2) navigation
    From: Trevor Bell
    Date: 2010 Feb 1, 10:07 -0800

    I agree - this is getting interesting. I acknowledge that the first waypoint was nowhere near the great circle - that was the intention of the naval control service routings - to sail off the normal direct routes but what the calculations have shown is that the total distance using the different methods varies by only a very small percentage.

    Having re-read the 1941 inquiry into the Rangitane sinking I can confirm that the waypoint coordinates I have given are correct but I realise that there was another error in my previous post: I said that the NCS told the captain to sail a great circle route between waypoints. This is wrong - he was told Mercator but the captain said at the inquiry that he may have sailed great circle. From various other enquiries I have made I understand that it was virtually impossible to sail a great circle because of continuous changes in heading so the great circle was broken up into a series of rhumblines. If he had sailed an approximated great circle, this makes the position of sinking (see previous post 11695) much more acceptable at about 35nm, but still off course.

    Just to lay another issue to rest - there has been some discussion in other posts about me using the term 'whole circle' instead of 'great circle' - sorry about that, it comes from my background as a civil engineer in which we use the term 'whole circle bearing'.

    Trevor Bell
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