Feet-Inches-Eighths to mm

Discussion in 'Boat Design' started by Alexanov, Oct 25, 2016.

  1. Alexanov
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    Alexanov Senior Member

  2. messabout
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    messabout Senior Member

    Thank you Alex. It will be handy for some of us. I do not need it myself because I have a dedicated handheld calculator that does the thinking for me.

    In a perfect world we'd all be using the same measuring system. There are even some numeric differences other than metric/imperial in different countries In many places a presumably descriptive name like one billion, or one million, has a different number of zeros.
     
  3. Ike
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    Ike Senior Member

    I learned a long time ago to do the conversions in my head. 2.245 cm per inch. (round to 2.5 and it's easier.)10 mm per cm. 39 inches per meter (3.25 feet.) 39 in = 1 meter. But I do keep a calculator handy just in case I want more accuracy.
     
  4. RAraujo
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    RAraujo Senior Member - Naval Architect

    It's 2.54 cm per inch...
     
  5. Ike
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    Ike Senior Member

    You're right. Too many rum and cokes.
     
    Last edited: Oct 27, 2016
  6. daiquiri
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    daiquiri Engineering and Design

  7. Ad Hoc
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    Ad Hoc Naval Architect

    Why would you spend a lot of time converting??...boats are generally in metric units, unless from the US, or an old one.

    You may find the attached of use too :)

    View attachment Convertion Tables.zip

    Could not up load the simple excel file...so had to make a zip file to upload it.???
     
  8. daiquiri
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    daiquiri Engineering and Design

    AH, it is an .exe file - are you sure you have posted the right one? I am not opening it before you confirm that it is ok. ;)
     
  9. Ad Hoc
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    Ad Hoc Naval Architect

    Aahh...may be that's why then! Doh...

    But yes, it is an exe file..and perfectly ok to use. I open it no probs and been using it for years

    Just realised too, not an excel file...my bad (doing too many things at once brain not kicked in)...it is an executable...but is perfectly safe :)
     
  10. Rurudyne
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    Rurudyne Senior Member

    I, Captain Obvious that I'm, would like to point out that the way boats are traditionally laid out converting an old design to millimeters doesn't really make sense because the idea was often to get you close enough to achieve the intended results, not to achieve anything like watchmaker precision.

    There is nothing magical about the metric system that makes such a conversion inherently desirable. Millimeters or eights ... it's a boat, not a space shuttle. Go with what you got whichever it came in ... why make more work for yourself?

    (But if you really want to be contrary just to be contrary: use cubits ;) )

    I would be dubious of any attempt, for example, to convert Seabird's (or other classic boat's) plans without actually trying to build a new boat before distributing the new and improved metric plans. Especially if someone were to offer cnc cut files and not successfully built a boat from them first.
     
  11. daiquiri
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    daiquiri Engineering and Design

    Rurudyne - you are reasoning from the point of view of someone who lives in a country where miles, yards, feets and inches are used each and every day. :)
    In Europe 2ft 11 3/8" has no sensible meaning for the majority of people, unless it is transformed into meters, cm or mm.
    So it has nothing to do with watchmaking precision, the conversion serves simply to give meaning to imperial numbers, for people who use another unit system.
    Cheers
     
  12. messabout
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    messabout Senior Member

    You are quite correct Daquiri. It is rather unfortunate that we in the US have not yet joined the rest of the world. The SI system is much easier to deal with than our more complex scheme of dividing by twelve or sixteen or Five thousand two hundred eighty. If more precision is needed we do begin to think in terms of divisions of base ten like thousandths of an inch, even tenths of thousandths of an inch.

    So....The example, two feet plus eleven inches plus three eighths of an inch is a clumsy number to translate to metric measure.... 89.8525 centimeters. If building a boat we'd probably round that off to 90 cm which is really close to thirty five and seven sixteenths. Hello world, we are a bit behind the times here in the colonies.
     
  13. Ad Hoc
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    Ad Hoc Naval Architect

    Hi D
    Did you try it??...it is very neat, full of weird units only those using old Imperial units understand.
     
  14. daiquiri
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    daiquiri Engineering and Design

    I have tried it AH, and looks like it has every measurement unit the humanity has ever concieved. :D
    I've saved it and placed a link to it on my desktop. Thanks!
     

  15. Heimfried
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    Heimfried Senior Member

    Found a mistake in the linked Convertion Tables.
    Dekameter (= 10 Meter = 10 m) is abbreviated with dm, it has to be dam instead.

    dm means Dezimeter = decimeter = 0.1 Meter = 0.1 m
     
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