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  1. #1
    Senior Member max111's Avatar
    Join Date
    Jul 2004

    interesting new mast extension idea

    this is a very clever idea

  2. #2
    Senior Member Navegante's Avatar
    Join Date
    Dec 2010
    40 48'N 14 26'E -Western Med - West South Atlantic
    Quote Originally Posted by max111 View Post
    this is a very clever idea

    You still need to pull on a string. It is a purchase system. I don’t see the real advantage if you have to disengage the mast from the mast base to pull on the second end string. He is still using the harness bar to pull.
    More over he could be pulling from both ends to have even more power.

    The North ratchet lever allows you to do it without separating the rig with one click a the time one hand and without putting your foot on the mast end to create purchase force, which may mean being back at the beach if there is one.

    Really I don’t get it. Two purchase systems in one when one usually just simply does the job.
    It seems to Me this is a case of reinventing the wheel without reinventing it.
    Like having a wheelbarrow with two wheels together at the centre front.

    Thinking more about this, probably the first traditional pulleys aren’t necessary only a shackle to keep the sail tack close to the extension base and then pull from the internal pulley system. This will solve the tack of the sail being distant from the extension.

    Still the sail looks terrible at the cambers bellow the boom.

    What am I missing?

  3. #3
    Senior Member
    Join Date
    Apr 2005
    Its interesting, but looks like it is heavier and more expensive than something which can get the same result (in a little more time).

  4. #4
    Senior Member
    Join Date
    Nov 2015
    I think what it misses is that you don't need to thread the standard system! If you just had a hook then it would take out the process of threading the rope! I quite like it but it needs that last little bit. A 3 pronged pulley block type thing might do the trick.

  5. #5
    That's just dumb.
    It now uses two lots of rope and pulley sheaves where in a normal extension there was one.

    It saves no time at all.
    It adds weight to the extension.
    It weakens the extension used in any RDM mast – and would probably only work for SDMs.
    It increases wear and tear on the extension because the collar is now sliding up and down under load.

    What problem does he think he is solving?*

    *I suppose the main benefit is for those who don't know what setting their extension should be on. Which is why most sailmakers already write the recommended extension setting on the sail.
    Last edited by basher; 29th April 2018 at 01:46 PM.
    Now back in the UK.

  6. #6
    Quote Originally Posted by max111 View Post
    this is a very clever idea
    That is very clever: it eliminates pins or any other kind of clumsy adjustment system in a blink (not to mention getting rid of the holes in the tube) and it allows the length of the extension to self adjust to any length: you will never have to adjust your extension again.

    The system could be even simpler, eliminating the primary pulley, if sails had a ring instead of a pulley at the bottom, like they used to have.

    Really excellent, too bad that it would probably never work for RDM otherwise I'd get it in a blink!
    Last edited by duzzi; 30th April 2018 at 04:10 PM.

  7. #7
    Glad somebody likes it.
    But there are still holes in the tube, and that tubing will be much heavier with the recesses and with sheaves fitted internally.
    If something snags up within the tube then de-rigging also becomes a nightmare (which is maybe why he has left the external downhaul system fitted).

    It also applies extension via a rope, and not via a fixed point, so the rig bounces downwards against a rope as you sail along. The more extension you use the more the rope will give.
    The quality of rope used then becomes critical. The whole rig weight is taken by the rope.
    The longer the extension, the more rope you use.
    (The SDM extension shown in the video is only a very short one.)

    It is also still a 'purchase' system for adding downhaul to your sail, and one with more fiction, given the collar has to move on the extension.

    The only plus about this system is that it adjusts mast extension with downhaul load. If you are forever rigging and de-rigging to adjust your extension lengths (because you don't know your correct settings) then this may appeal.

    I'll happily stick with the trouble-free pin system thank you.
    Last edited by basher; 30th April 2018 at 09:49 PM.
    Now back in the UK.

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