Log format conventions in Hudson’s Bay Co. ships

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  • #16094
    Michael Palmer
    Participant

    Some years ago I found the logbook of a schooner in local service (in Hudson’s Bay) in the 1830s. The layout when at sea is a page per day running noon to noon and dated for the day commencing at midnight halfway down the page (the noon sight is therefore the last entry on each page and relates to the date given at the top)
    Columns are headed :-
    H (Hour, = time); K(nots); F (?);Courses (steered); Winds (Direction, and strength by pre-Beaufort description); Unheaded but in other logbooks of the time – Leeway; Remarks.
    My question – What could F be? It is recorded in single digits, and does not correlate with ships movement (or lack of it- in one place F is recorded as constant, ie by a whole column of dittos, whilst the schooner was grappled to an ice floe overnight unable to make progress) – sea state, visibility, Tide, compass variation (noted in Remarks column when calculated from the direction of the setting sun) or Depth. It is tempting to think that F is the initial letter of the unit of measurement as with H and K, since column-width is allowed for the whole word where there is no unit (as with “Courses” )
    My remaining candidate is not a strong one – Sea temperature in degrees (Farenheit) above freezing. But why such a prominent position among the items so necessary for navigation.
    What am I missing here?
    Mike Palmer

    #16098
    David Hepper
    Participant

    F = Fathoms

    Speed was measured with a log-line: the log was a triangular wooden board, secured to a line, which was streamed from the stern. For the first 10 or 20 fathoms the line was unmarked, and then this ‘stray’ was marked with a piece of bunting. After that the line was marked with a knot every 50 feet – using a 30-second glass, the number of knots that passed over the stern was recorded, plus the number of fathoms of line above the last knot. These figures were then recorded in the log as K(nots) and F(athoms)

    #16101
    Frank Scott
    Participant

    David Hepper is right to have the F column as Fathoms.
    If you want more detail on the ship log, see my note, ‘Speed, Navigational Accuracy and the ‘Ship Log’ in Mariner’s Mirror vol 92:4 (2006), 477-81. In particular this discusses the various ‘sand glass’ timings used (normally 28 seconds for the British) and the wide variety of knot spacings.
    By the way the division into eighths (or less commonly tenths) of a knot seldom equated to true fathoms, even though it was recorded under the heading of ‘fathoms’

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