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Mast step base area

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  • 08 Apr 2017 00:02
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    Reply # 4735578 on 4721549
    Anonymous member
    Scott Dufour wrote:And in response to too many confused looks by those who don't speak the Buddha's ancient language of Pali, the name Mudita, meaning, "joy unencumbered by self interest" has been replaced with Moon River, meaning, "Two drifters off to see the world".
    Ah, is that what it means?  'Joy, unencumbered by self interest' is such a Buddhist concept, although I should have thought that too much self interest is obviously an antidote to joy.  Alas, in my mind Mudita translated to 'little muddy one', so maybe Moon River will lead to less confusion.
  • 07 Apr 2017 18:33
    Quote
    Reply # 4730739 on 4075065
    Deleted user

    Thank you, Arne.

    From your photos and the file you emailed to be (that's going to be a great article), I think I've got a good sense of the scale now.  I like your method, because it matches the materials and processes with which I'm comfortable.

    I think, then, that a mast step that's simply wide enough to accommodate the mast base and thick enough to withstand the pile-driving forces of the mast, ought to have by default enough hull contact area to hold tight.  But in the spirit of overkill, I'm going to tab mine to the hull with 6" 1708 biaxial fiberglass tape, just like I do the major bulkheads.  I suspect that will ensure that it's the only part of the boat remaining after a bomb goes off.
  • 07 Apr 2017 15:23
    Quote
    Reply # 4721787 on 4075065
    Anonymous member (Administrator)

    Scott,

    I certainly don't think I know it all when it comes to making a good mast step. For those who are used to working with glass and polyester, the step could just as well be built up that way.

    However, I find the two-step method of making a plywood maststep to be easy to do, although slow. The idea is to make the base very rigid so that any sideforces are shared equally over the whole contact area with the hull. The upper section of the mast step, sitting on top of the base, is made a bit smaller to let one test-fit the mast before stirring epoxy. I have quite a few photos in one of my albums. If you start here, and step forward, you will get an idea of the progress.

    Arne

    PS: I'll mail you an unfinished draft of "Junkrig for Ingeborg, Part 2" with some more text about it.
  • 07 Apr 2017 13:29
    Quote
    Reply # 4721549 on 4075065
    Deleted user

    Arne, this one's really directed at you! 

    It looks like this question got lost last summer, but I'm about to start work on the step, so I'm bumping it up. 

     

    (Parenthetically, the entire interior in those pictures is now completely gone.  Bare hull stem to stern.  And in response to too many confused looks by those who don't speak the Buddha's ancient language of Pali, the name Mudita, meaning, "joy unencumbered by self interest" has been replaced with Moon River, meaning, "Two drifters off to see the world".)

    Last modified: 07 Apr 2017 13:35 | Deleted user
  • 14 Jun 2016 18:07
    Quote
    Message # 4075065
    Deleted user

    Hey everyone,

    I plan on fabricating the mast step in place, per Arne's description of his plywood construction.  10" Mast diameter.

    What specs, though?  It'll be plywood epoxied to polyester resin fiberglass, de-waxed and prepped per the normal care.  I'm guessing about 2.5 inches of ply base, with another 2.5 inches of plywood collar.  But how about the area of contact with the hull?  I honestly have no eye for what would be strong enough.  Is there math here, or do we make do with "4 x the area of the cross section of the base of the mast", or something?

    The images below show the location with an 8" tube, not 10" like the mast will be.

    Mudita mast step location 1

    Mudita mast step location 2

    I decided to not use the 8" tubes because I did a multitude of calculations and decided that a concrete mast would be too heavy.  I'm clever like that. 
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