Graham,

I agree with Ric, the main halyard/Cunningham tension isn’t tight enough.  It also looks like the boom out haul isn’t tight enough.  The leech line on the trailing edge of the sail may also be too tight.  But, the luff tension and foot tension have to be correct before the leech line can be adjusted.  If either the halyard or the boom outhaul can’t be tensioned more; then, the mainsail was either made wrong or it may have stretched.  Either way, your mainsail would need some custom tailoring.

Roger Pihlaja
S/V Dynamic Equilibrium
Sent from my iPhone

> On Jul 18, 2023, at 4:53 AM, Ric Stott <ric at stottarchitecture.com> wrote:
> This looks to me like a halyard/down haul tension issue. It appears that you have a ‘Continental’ rig with a Stack Pc or Lazy Jack system. It should be easy to pull on some down haul to tighten the luff of the sail.
> Ric
> Dadventure.
> HBNY
>
> Sent from my iPhone
>
>> On Jul 18, 2023, at 2:59 AM, Graham Stewart <gstewart.gm at gmail.com> wrote:
>>
>> My mainsail hangs with a diagonal crease that I can't seem to get rid of.
>> The sail was new a few years ago and was purchased while I was restoring
>> the boat - which included replacing the inner stay chainplates. I also
>> changed the furling gear and afterwards it seemed that the inner aft stays
>> and the aft stays were shorter than before.
>> Might the rake of the mast create this problem or might it be a
>> poorly constructed sail? I have attached a picture in case one of the
>> expert sailors on the list can make a suggestion.
>> Thanks,
>>
>>
>> Graham Stewart
>> Agile 76
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