Mast stepping with sheer legs

  • 02 Nov 2018 23:44
    Reply # 6886359 on 6884742

    Thanks David for your comment. I talked to a carpenter and builder friend today about size and stability. Conclusion is to take 20 ft long 2x4s and 2x6s and glue and screw them with construction screws together, so that the profile is a T. This gives more rigidity with less weight than a 20ft long 4x4.

    Taking your advice I will tie them down with a for- and a back stay, the top will have a bracket wide enough to give room for mast and blocks angled to allow the sticks being safely attached to the deck.

    I might just try them out on the ground away from any other boat with the same load.

    The stays can be tied down with cork screws.

    I am open for any more suggestions - Ed

  • 02 Nov 2018 13:45
    Reply # 6885482 on 6884742

    I've stepped a mast of that length (but much lighter, about 40kg), using a single spar, mounted vertically just to one side of the partners, and stayed with three or four stays to cleats and other strong deck fittings. The mast was laid on deck, heel forward. It took one person to hoist the mast using a tackle, one person to guide the heel and one person to adjust the stays (with great care) so that the mast was vertically above the partners. Obviously, with both a single spar and an A frame, they must be long enough that the tackle has plenty of drift so that the mast does not contact the spar(s). 

    A catamaran in Ravenglass harbour has a high wingmast, and sheer legs are used to lower it. They are made from large diameter aluminium tube, and the owner says that he almost needs sheer legs to hoist the sheer legs, they are so heavy. 

    Unless the operation is to be carried out frequently, so that you stay in practice with the methods of handling heavy equipment safely, it might be better to engage a crane to do the job. 

  • 01 Nov 2018 20:27
    Message # 6884742
    After searching for quite a while here and the web I like to approach the JR family with my question about stepping and un-stepping 33ft 220lb light-pole masts with sheer legs.

    I'm new here, recently purchased a 36 Bruce Roberts PH Junk and had it trailered 1000 miles from Quebec to Nova Scotia. After many years on the hard she needs a bit attention especially the hull.

    We were looking for steel, full keel, PH and Junk to explore the Maritimes - couldn't be more happier.

    In Hasler/McLeod's Practical Junk Rig on pages 198-200 it is written about using sheer legs, but unfortunately no size info for the spars.

    I was talking to a sawmill owner and he suggested two 2x4 glued together to eliminate the failure with knots and maybe taper them just for elegance.

    Any advice is much appreciated

    Last modified: 01 Nov 2018 20:28 | Anonymous member
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