Free-Stand my Shrouded Steel Mast, or Weld Spreaders?

  • 31 Jan 2020 11:13
    Reply # 8703929 on 8702367

    Hi dude!  It seems like a long time since we were in the Whitsundays together.  Unstayed masts are the best but you would need to replace the ones you have, which is a big job, might even need to strengthen the partners, though steel boats are strong!  Maybe the spreaders would be the best compromise.  I suspect the shrouds will always be a hassle, but the spreaders should make it easier.

  • 31 Jan 2020 05:30
    Reply # 8703723 on 8702367

    The mast is not strong enough to be free standing. Do what the Chidels did or invest in a new mast that is designed to be free standing.


  • 30 Jan 2020 17:53
    Reply # 8702860 on 8702367

    just by free guessing, 6" in diameter with a 5mm wall doesn't sound strong enough for your ship.

    depending on the execution of the welding your mast might have a breaking strength of something around 3000 kpm.

    ueli

    Last modified: 30 Jan 2020 17:54 | Anonymous member
  • 30 Jan 2020 14:40
    Reply # 8702440 on 8702367
    Deleted user

    Also, the mast is steel, spiral welded from a long rectangular sheet to make a 6 inch diameter round tube. 40 ft from deck to mast top. The walls of the mast is 5 mm thick.

  • 30 Jan 2020 14:10
    Message # 8702367
    Deleted user

    Hello,

    my boat, Madam Wong, is a steel Colvin, 3 masted schooner (issue 76 cover). The mast has 3 standing shrouds per side for the main and mizzen, 2 per side for the foremast. Total is 6 + 6 + 4 = 16 shrouds. 

    The problem is when I need to reef a panel, the yard has extra freedom to swing (I installed a yard parrell already). The front of yard sometimes jams on the shrouds, usually between the front and mid shroud. The shrouds also chafes on the sail and the yard, when squaring off for downwind. So I tend not to ever reef, even though I should!

    1. I can plug my mast with a wood plug, like in

    https://alberg37junk.wordpress.com/category/junk-rig-design/

    to make it a free standing mast. But I'm not sure if the mast will be strong enough, anybody knows the calculations for that? I think I may have find out my boat's actual righting moment (hang the dinghy on the side, put a heavy load, and measure heel) and a bunch of other number crunching. 

    2. Or weld spreaders (the Chidells did this on Tin Hau). 


    Any thoughts?


    Thank you,

    Vo

    Last modified: 30 Jan 2020 14:11 | Deleted user
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