Arne Kverneland wrote:..

I think that from now on, I will let the “default” position of the halyard’s slingpoint be about 3 – 5% aft of the yard’s midpoint. To achieve this, the mast must be long enough, so the halyard will not point over 30° away from the mast, with the sail fully hoisted.

Yes, I will try this on the foresail. Thanks.

Batten loads  - and about moving the slingpoint aft

Reading through this thread confirms my belief that it is not easy to make a general formula to find the right strength of battens.

 

It surprises me to read how Gary King bent his battens at the mast. My experience is that the battens seems to struggle mostly in the mid section.  David Thatcher’s idea with hybrid wood-aluminium is interesting. Since the wood is in the fwd end, it will not suffer high peak loads at gybing.

 

 

One thing I learned from sailing my latest boat, Frøken Sørensen, last summer: Since I was more generous with mast length this time, I tried tying the halyard a bit aft of the middle of the yard. This seems to have these benefits:

1.       The sail is immune to dropping the peak when hoisting or reefing the sail.

2.       With the aft-set slingpoint the need for high control forces in the YHP and THP will be reduced. Maybe this could ease the loads on batten no 2, or?

 

 

I think that from now on, I will let the “default” position of the halyard’s slingpoint be about 3 – 5% aft of the yard’s midpoint. To achieve this, the mast must be long enough, so the halyard will not point over 30° away from the mast, with the sail fully hoisted.

 

 

Cheers, Arne

Gary King wrote:Just had a read of Oscar's batten DB and I'm speechless. Ashiki has the strongest battens yet only hers bent. I don't know what to make of that..

Maybe everyone else has T6.

The three alloy battens on Footprints are T5. I am amazed that after two years including our voyage to New Caledonia that we have not had any issues with them. The battens are 60mm diameter with from memory a  1.5 mm wall thickness. I have 5m of alloy batten with an extra 1.5m of cedar extension on the fwd end making a total batten length of 6.5m. The battens have survived numerous crash gybes plus the rigors of two ocean crossings.

To answer Gary's original question and get back on topic, the answer is Yes, try the Batten Spec Database in the Join In 'JRA & Members' Projects' forum here.

I'm not sure that this project has got as far as it's coordinator Oscar would wish. It can be a little tough beavering away at that kind of stuff. Perhaps others would, like Paul Thompson, try to help via that thread?

David Tyler wrote:What's the temper of the alloy, Gary? I suspect it's T5, which is all I could buy in Oz, and that let me down, too, whereas T6 shouldn't/wouldn't have done.