1940 Convoy: Distances 'twixt columns, ships, & c. information request

Discussion in 'The War at Sea' started by papiermache, Mar 11, 2020.

  1. Roy Martin

    Roy Martin Senior Member

    Robert,
    Yes a nuatical mile was 6080 feet, so a cable is 608. I don't remember there being any change, though several websites get mixed up with a length of anchor chain - 15 fathoms or 27.5 meters.

    Roy
     
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  2. Robert-w

    Robert-w Banned

    Not in the immediate past but as one goes back in time it did vary which can make some historical accounts misleading
     
  3. Harry Ree

    Harry Ree Very Senior Member

    Roy...... Interesting constants for seafarers as you point out.

    1 Sea Mile = 6080 feet which is 2027 yards,say 2000 yards for practical considerations,a Cable being one tenth of a Sea Mile.

    But an interesting constant for sea passage is 1 Knot = 1 Sea Mile per hour is 101.3 feet/min and for practical considerations,100 feet/min.

    Constants unamended and outside of the SI System
     
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  4. Roy Martin

    Roy Martin Senior Member

    Robert,
    Unless I am mistaken the original question was about convoy distances in 1940.

    I don't know of any variation in the length of a British cable - ignoring a long discussion in the earth being an oblate spheriod and the length of a nautical mile varying slightly with latitude. It is true that the French and others decided on a slightly different cable length.

    But this is the nautical equivalent of rivet counting.
     
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  5. Robert-w

    Robert-w Banned

    The 1937 Edition of the Admiralty Manual of Seamanship says "The 'Cable' appears as a measure of distance in older nautical writing and seems to refer to a different value depending on who is speaking." hence my original comment
     
    Last edited: Mar 12, 2020
  6. papiermache

    papiermache Well-Known Member

    The 1837 edition of "The Naval History of Great Britain" by William James has this.

    Cable 2.jpg
     
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  7. Roy Martin

    Roy Martin Senior Member

    At my age I ought to know when to shut up! but:

    A cable's length and a cable are two different things.Rope was supplied in 120 fathom coils (220 meters). Early ships used rope to connect to their anchors, hence a cable's length. Later ships used chain, hence chain cable or anchor cable.
     
  8. Tricky Dicky

    Tricky Dicky Don'tre member

    Roy

    I find your posts educational and factual, thanks - keep going in spite of .....................................

    TD
     
  9. Roy Martin

    Roy Martin Senior Member

    Thank you TD,
    I find your posts most interesting and informative.

    Roy
     
  10. BaldyBob

    BaldyBob Junior Member

    I still use the 'cable' as a reference of distance.
    185.2m (we have gone metric!), being 1/10th of a nautical mile (or 6 seconds of latitude if we really want to confuse the issue :wacko:)
     
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  11. papiermache

    papiermache Well-Known Member

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  12. papiermache

    papiermache Well-Known Member

    Admiral Smyth states:

    " CABLE'S LENGTH. A measure of about 100 fathoms, by which the distances of ships in a fleet are frequently estimated. This term is frequently misunderstood. In all marine charts a cable is deemed 607.56 feet, or one-tenth of a sea mile. In ropemaking the cable varies from 100 to 115 fathoms; cablet, 120 fathoms; hawser-laid, 130 fathoms, as determined by the Admiralty in 1830."

    Anyone still CABOBBLED ( Confused or puzzled) ? Smyth 1.jpg

    Smyth 3.jpg
    Smyth 4.jpg
     
  13. Tricky Dicky

    Tricky Dicky Don'tre member

    No - but I now need to know what a Bitt is, I also like the original spelling of Kebab (Cabob/Kebaub)

    TD
     
  14. Roy Martin

    Roy Martin Senior Member

    a double steel/iron bollard that you tie mooring ropes to.
     
  15. Tricky Dicky

    Tricky Dicky Don'tre member

    Thank you sir - I'll be asking what a Panama Fairlead is next :D

    TD
     
  16. Roy Martin

    Roy Martin Senior Member

    I think it is somewhere you store your Panama hat
     
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  17. timuk

    timuk Well-Known Member

    Hope you wrote this for the benefit of the landlubber Forum members. My old and bold CPO Seamanship Instructor would have :reallymad:as he drummed into us "Shoe laces are tied up, ships and ropes are secured". :);)

    Tim
     
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  18. timuk

    timuk Well-Known Member

    Back to convoys. It has to be remembered that station keeping in the convoy very much depended on the Officer of the Watch and the Mark 1 eyeball. There was the handheld optical rangefinder but this is was difficult to use in much more than a calm sea as it depended on measuring the angle between the top of the ship's mast and the water line.
    Abstracted from Signalman 1 & C
    upload_2020-3-13_13-19-5.png
    Abstracted from Cruising Order - Convoy OS.33 this is the Cruising Order for OS33 where it can be seen the masthead height for each ship is given.
    upload_2020-3-13_13-17-42.png
    Tim
     
  19. Robert-w

    Robert-w Banned

    I've seen accounts from both WW1 and WW2 that suggest that some merchant skippers were not always that good at maintaining station and had to be harangued by the escorts usually by Aldis or flag (radio silence being maintained) which they sometimes were slow at reading (and there were often some for whom English was not a first or even a second language). This cannot have helped matters
     
    Last edited: Mar 13, 2020
  20. papiermache

    papiermache Well-Known Member

    Here be "Bitts" etc. from Admiral Smyth.

    Also extracts from a book estimated to be published in about 1835 which fails to mention cables. A lot of pages about decimals. " To find the distance of objects at Sea by Means of the Curvature of the Earth."

    Finally a link to a First World War film at NARA. If you can get to 60 seconds in without feeling seasick there is a picture of three Germans trying to "shoot the sun".

    Bitt 1.jpg

    BITT 2.jpg

    Norie 1.jpg

    Norie-2.jpg


    NARA film link

    https://catalog.archives.gov/id/24670
     
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