Topping lift strength

  • 10 Jun 2018 13:51
    Reply # 6301707 on 6300285
    I’m so relieved I happened to ask this; I would’ve probably taken the strength demand issue too lightly. The value of this forum is in it’s own league.
    Last modified: 10 Jun 2018 15:36 | Anonymous member
  • 10 Jun 2018 02:04
    Reply # 6301318 on 6300285

    If you go for a sail catcher like David, then you can have very thin topping lifts, because the sail catcher will prevent  the chafe, as long as they are UV resistant.  Otherwise, however, I am in complete accord with Arne. 

    The topping lifts are probably the most important length of line on the rig and the most difficult to replace at any time, let alone in extremis.  On Badger, we fitted 6mm line for the topping lifts: this didn't chafe the sails and was theoretically strong enough.  However, after only a couple of years, the UV had attacked it sufficiently that one of them snapped after gybing, causing the reefed sail to tumble down on deck.  There was too much wind for full sail and we were lucky that we had two sails and could sail under the other one to find anchorage and repair the lift, having no engine.  (We were also fortunate to be coastal sailing at the time.)  As soon as we could, we replaced them with thicker rope, and I put 10mm on Fantail's rig.  I don't suppose UV damage is much of a consideration in Scandinavia, but the importance of the topping lifts in the rig cannot be over-emphasised.

  • 09 Jun 2018 10:52
    Reply # 6300343 on 6300285
    Anonymous member (Administrator)

    David,

    I can see your point. From a strength and windage point of view, a thin Dyneema line would be just fine. When I suggest following PJR's suggested size, it is more because of Hasler & McLeod's argument that a thicker rope is less prone to chafe the folded sailcloth.  

    One could, of course have a thick rope (or webbing) for the lowest half metre of the topping lifts, to protect the sail bundle, and then use Dyneema on the rest.

    Arne

    PS: There are two areas where I deliberately go for oversize scantlings:

    • Mast step and the prevention of the mast from 'unstepping' itself.
    • Topping lifts
    The reason is that if these fails, one suddenly has huge problems. Unlike over-sizing the mast, the overstrong mast step and topping lifts are cheap and easy to fit, and will hardly rob much of the boat's performance.
    Last modified: 09 Jun 2018 11:08 | Anonymous member (Administrator)
  • 09 Jun 2018 09:59
    Reply # 6300324 on 6300320
    Arne Kverneland wrote:


    According to PJR’s table your topping lifts should be 10mm. I prefer 3-strand rope for these, as they let me splice them. My guess is that the most slippy  monofilament rope is kindest to the sail.

    Good luck!

    Arne

     


    10mm, on a 22ft boat? Really? That's enormous! From memory, I think I used that size on Tystie, at 34ft.
  • 09 Jun 2018 09:42
    Reply # 6300321 on 6300285

    The topping lifts only have to carry the weight of the sail bundle in normal service, so modern cordage has no difficulty in coping. I find bare 4mm Dyneema very effective, being extremely strong, with no stretch,  and UV resistant and chafe resistant. The absence of stretch is the most important thing. Not critical, though, and 6mm braid on braid polyester will do.

  • 09 Jun 2018 09:36
    Reply # 6300320 on 6300285
    Anonymous member (Administrator)

    I would follow Hasler and Mcleod’s advice and use ‘ample  strength’ for the topping lifts.

    They give three reasons (PJR p.178)  -  shortened by me, here:

    ·         The weight of the bundle. I will add that when sailing deeply reefed, many of the sheetlets will work on the furled bundle, and thus increase the load on the topping lifts.

    ·         Small diameter topping lifts cut and chafe the sail more than larger diameter versions.

    ·         The consequences of a broken topping lift at sea is very serious.

    Here is what I wrote about topping lifts in my “Junk Rig for Beginners”

    “..Lazy Jacks...

    Most sailors have seen some sort of lazy jacks in use on gaffers and Bm-rigged boats. Little do they know that these “modern gadgets” have been in use in China for well over 2000 years. Unlike the western rigs, where the lazy j. are nice to have, on the Chinese JR they are absolutely essential, as the JR reefs by lowering the sails into the lazy jacks. This means that the lazy jacks must be made from stout chafe-resistant rope and be checked, maintained and replaced with the same regularity as the halyard.”

    According to PJR’s table your topping lifts should be 10mm. I prefer 3-strand rope for these, as they let me splice them. My guess is that the slippiest  monofilament rope is kindest to the sail.

    Good luck!

    Arne

     


    Last modified: 10 Jun 2018 11:48 | Anonymous member (Administrator)
  • 09 Jun 2018 08:31
    Message # 6300285

    I’ve started riggng the sail for my Galion 22. I have diffuculties in defining the strength needed for the topping lifts/lazyjacks.

    The sail bundle weighs around 15-20kg, I think.

    What kind of forces affect the topping lifts - how much should they be able to cope with?

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