[Public-List] Mainsheet diameter

[Gordon Laco]

We’ve got SURPRISE’s mainsheet rigged 3:1, so the load in the hand is somewhat higher.  That led me to use 5/8”, not for strength, but for comfort.  I fitted blocks large enough to handle this comfortably, so there’s no issue with friction when it’s running out.

I used to have 3:1 with the option of pulling down the dead end to make it 4:1 as originally rigged, but found years went by without the need for this, so 3:1 it is.

I like 3:1 because when rounding the leeward pin there’s so much less sheet to haul in when starting back up the course... and of course the lack of the extra turn in the tackle relieves friction.

Funny thing about friction and blocks... Harken has us all trained to feel we need ball bearings but the fact is that ball bearings are only superior in narrow circumstances, and always in low load situations, such as light air sheeting and easing. (that goes for things like outhauls etc too).  Plain bearings (stainless steel on bronze) are best in high loads with regard to both strength and low friction when hauling in.  And, (here comes the real heretical observation) this is true for winches too...

But I’m sure most won’t believe it...

Gord
 #426 Surprise

On 2017-10-31, 1:08 PM, "Public-List on behalf of Stephen gwyn via Public-List" <public-list-bounces at lists.alberg30.org on behalf of public-list at lists.alberg30.org> wrote:

    The mainsheet, with it's 4-to-1 purchase, is never under very heavy load.
    The diameter is more about what's comfortable in the hand. I use 10mm
    which works out to somewhere between 1/2" and 7/16", but closer to 1/2".
    It's fine. The jib sheets are single lines, and listening to the sound
    as they are tightened and doing some undergraduate physics, the tension
    is sometime 700lbs, still much less then the breaking strain of 10mm
    polyester line.
    
    SG
    
    
    
    On 10/31/2017 07:28 AM, public-list-request at lists.alberg30.org wrote:
    >   Great resource, thanks George.
    > Is everyone using 7/16" for the mainsheet? I planned on 1/2", bad idea?
    > Thanks
    > Chris
    
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