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Thread: Gaff jaws

  1. #1
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    Default Gaff jaws

    This is a short article on gaff and boom jaws that appeared in Woodenboat #59, back in the 80's. I hope I'm not transgressing by posting this and will take it down if asked nicely. I've found the diagrams most helpful on several occasions. The details deal with larger masts using a tumbler on the jaws. The boom jaws are rather archaic, but interesting, nonetheless. They are worth careful study...











  2. #2
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    Default Re: Gaff jaws

    thanks for that, Im trying to get my head around how the saddle (tumbler?) is going to interact with those brass strips as the boom and gaff rotate...

    this appears to be for a rather larger rig than many of us use.
    thankfully I've got Centennials actual gaff and lots of ideas from Chapelle's fishing schooner book and a rig plan of 1910 Essex built racing Gloucesterman Eleise to draw from. I have elected to leave off the saddle on the boom.

    I'll be in Essex today for work, maybe swing by the old Story yard and have a look at a few in person, thanks for the inspiration Jim.


  3. #3
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    Default Re: Gaff jaws

    Thanks for that, Daniel, I love that picture.

    While the design might be for rigs larger than many homebuilt craft the proportions should scale down well. I just about copied this when making Sea Rovers spars. Sea Rover was a catboat built in 1916, twenty-five feet long. This is her gaff being refinished, which shows many of the details of the diagrams. Interestingly, she had boom jaws and a saddle around the mast as shown in the diagram. Nowadays this would most likely be done with a bronze gooseneck.


  4. #4
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    Default Re: Gaff jaws

    Those are nice. The spar is tapered and the legs of the jaws are nice and long so they can be riveted, not like some of the fat clunky affairs that I have seen. I fear that with the demise of rivets and the ascendancy of screw fastenings, knees and jaw legs have become fatter so there is space for the screw and the bung. Joe Liener showed me how to make really long rivets with lengths of heavy copper wire, I think number 2, which work fine for jaws. A source for curved grain material can be a bit of oak with a really big knot in it; the grain flows around the knot.
    Ben Fuller
    Ran Tan, Liten Kuhling, Vernon Langille, Josef W., Merry Mouth, Imp, Macavity and a quiver of unamed 'yaks.
    "Bound fast is boatless man."

  5. #5
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    Default Re: Gaff jaws

    Quote Originally Posted by Ben Fuller View Post
    Those are nice. The spar is tapered and the legs of the jaws are nice and long so they can be riveted, not like some of the fat clunky affairs that I have seen. I fear that with the demise of rivets and the ascendancy of screw fastenings, knees and jaw legs have become fatter so there is space for the screw and the bung. Joe Liener showed me how to make really long rivets with lengths of heavy copper wire, I think number 2, which work fine for jaws. A source for curved grain material can be a bit of oak with a really big knot in it; the grain flows around the knot.
    Thanks, Ben. I think that the tapering of the spar under the jaws improves things from both an engineering standpoint as well as as the aesthetic. The spar is much reduced at the end, reducing exposed end grain and eliminating wood where it does little good. The jaws are correspondingly wider, adding wood where it's needed to strengthen the jaw and reducing the gap between the jaws, which allows a narrower tumbler. The overall look, compared to no taper, is much easier on the eyes

  6. #6
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    Default Re: Gaff jaws

    Quote Originally Posted by Jim Ledger View Post
    This is a short article on gaff and boom jaws that appeared in Woodenboat #59, back in the 80's. I hope I'm not transgressing by posting this and will take it down if asked nicely. I've found the diagrams most helpful on several occasions. The details deal with larger masts using a tumbler on the jaws. The boom jaws are rather archaic, but interesting, nonetheless. They are worth careful study...



    I agree, the boom jaws are over complicated compared with what works on my coast, the tumbler is OTT as is the parrel line, and I do not like that downhaul.
    It really is quite difficult to build an ugly wooden boat.

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  7. #7
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    Default Re: Gaff jaws

    Made a set of boom jaws this afternoon, didnt take any pictures cos it pretty basic, but as someone started a thread....

  8. #8
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    Default

    That was an interesting read, Jim. Thanks for spending the time finding and posting the article. I may well need to re-look at what I am planning...

    My Oughtred plans say to laminate the jaws for the gaff in 8mm layers. Those documents you posted seem to suggest doing them as a one-piece job. Any thoughts as to which way to go? My mast is only 60mm diameter...

    Thanks

    Noel


    Sent from my iPad using Tapatalk Pro

  9. #9
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    Default Re: Gaff jaws

    Quote Originally Posted by Racundra View Post
    That was an interesting read, Jim. Thanks for spending the time finding and posting the article. I may well need to re-look at what I am planning...

    My Oughtred plans say to laminate the jaws for the gaff in 8mm layers. Those documents you posted seem to suggest doing them as a one-piece job. Any thoughts as to which way to go? My mast is only 60mm diameter...

    Thanks

    Noel


    Sent from my iPad using Tapatalk Pro
    Peerie's mast is thicker than that, her jaws are shaped from solid tree wood.
    It really is quite difficult to build an ugly wooden boat.

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  10. #10
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    Default Re: Gaff jaws

    Sure looks like a Herreshoff 12 1/2 gaffer re-rigged with what looks to be a main sail track slide added to the end of the gaff. I suspect that the jaws are really cosmetic especially since there is no leathers or bale and the track side does the job.

  11. #11
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    Default Re: Gaff jaws

    I don't like the half oval brass strips. They seem to be asking for a snag. Using his logic would you not also want to have strips at the full hoist and the various reefing heights?

  12. #12
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    Default Re: Gaff jaws

    Thanks for posting the article. It's a great example of the "old" WB Magazine, back when guys like Bill Garden and "Pete" Culler would write useful articles about traditional wooden boat building in which they shared lifetimes of experience in their craft. Even as late as the '80's, I doubt you'd find any articles about building plywood boxes held together with PL Premium and wrapped in fiberglass and epoxy. Nostalgia ain't what it used to be, as they say.

  13. #13
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    Default Re: Gaff jaws

    'Tumbler', 'Saddle', have i heard it called the 'Clapper' too?

    Hence the phrase "To go like the clappers", meaning fast, as if the wind were full bore and the sails trembling causing the clappers to.....clap...?
    Have i just created an urban myth?
    Why is 'Politically Approved' speech better than 'Politically Correct' speech?

  14. #14
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    Default Re: Gaff jaws

    Quote Originally Posted by gypsie View Post
    'Tumbler', 'Saddle', have i heard it called the 'Clapper' too?

    Hence the phrase "To go like the clappers", meaning fast, as if the wind were full bore and the sails trembling causing the clappers to.....clap...?
    Have i just created an urban myth?
    Think of the clapper in a bell, and the ringing of a peal 6 - 8 - 12 bells ringing a full change. Or better yet, the clapper in a fire engines bell.
    It really is quite difficult to build an ugly wooden boat.

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  15. #15
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    Default Re: Gaff jaws

    I questioned the half-oval brass strips as well. Seems to me that the snagging (though not likely, if properly dimensioned) / position on the mast issues can be easily resolved by mounting the half-ovals on the jaws themselves. On the other hand, isn't that what the jaw leather is all about?
    "... the door was ajar, and the game was afoot." Lawrence Block

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