With no intent to offend, your sail simply isnt raised properly.
You havent 'stretched out' that boltrope ... and the sail will be 'baggy', draft aft (the pic shows it), the leech beginning to 'hook to weather' (it is).
A CAt 30 mainsail has the following dimensions ( to see if the boltrope has become shrunken) ... A boltrope 'usually' has to be 'eased' after about each ~200-300 hours of 'hard' sailing:
***** Luff 35*ft (10667mm)
Foot 11.5*ft (3505mm)
Leech-AftHdBd 36.22*ft (11039mm)
******* Tack Angle 88 deg. angle that the ''cloth side''' of the boom makes with the mast !!!!
Diag (clew/head) 36.46*ft (11113mm)
Head (inches) 5.25*in (133mm)
Area (no Roach) 207.78*ft2 (19303mm2)
For a Cat 30 with 35ft. luff ... release vang, mainsheet, outhaul, topping lift, etc. ... completely, then raise the sail so that its 'just up', then (important) apply THREE extra inches of halyard strain.
Measure the angle that the sail side of the boom makes with the mast --- should be approx 90 degrees (88 actually) - just use a large sheet of paper/cardboard.
If with 3 inches of 'extra strain' that angle at the tack of the sail is GREATER THAN 90 degrees (and the aft end of the boom is lower than the gooseneck (with the mast 'straight up') ... then the sail has a shrunken boltrope. Sometimes you can add EXTRA halyard strain to make the correction (to tack angle at 88 degrees). If greater than 90 degrees and the aft end of the boom is lower than the gooseneck ... take the sail to a sailmaker, get an evaluation of material condition and if OK, get that bolt rope eased. Most times, if you have a shrunken boltrope, that correction will do 'wonders' for the shape of an old sail.
Your pic shows the luff being quite loose probably by not correctly adding that halyard strain (or use of a cunningham if you have one).
Symptoms of a shrunken boltrope:
• aft end of the boom lower than the gooseneck,
• boat heels excessively but isnt 'fast'.
• leech begins to 'hook to weather' ... a curve towards windward at the aft end of the sail
• 'baggy' - LOTS of draft.
Anytime a sail develops 'girts' (creases) ... it means that one of the three sides of the sail doesnt have sufficient strain or has too much strain .... with the other two in reactance. Anytime you adjust ONE edge of a sail, girts will develop unless you ALSO adjust the other two sides. Did you leave your vang tensioned when you raised this sail when you took the pic?
A sail with a BOLTROPE is made with the boltrope purposely shortened by the sailmaker (usually 1" of shortening for 11Ft. of luff length) .... and the sail wont 'set' (at up to 15 kts.) unless you remove this 'preload' by halyard, etc. tension (... and then make various sail tension adjustments until the helm almost loses most of its 'weather helm').
That 35ft. listing of your Cat 30 luff dimension is 35 ft. **minus ~3 inches** so you have to give such a sail 3" additional halyard strain so you get the 'full hoist' and stretch out that boltrope so that you 'can' have a 35 ft. luff length. Without removing the boltrope 'preload' by the proper halyard strain, and if you only 'just raise', the aft end of the boom and the sails clew will be approximately 3 inches LOWER than the 'design' of the sail ... and the sail (in 15 knots of wind) will be draft-aft, baggy or at maximum/excessive draft, battens will easily 'hook to weather, etc.
General - Typical boltroped sails are 'preloaded' by 1" for every 11 ft. of luff length. Look up the luff length in ft., divide by 11 ... and thats how much 'stretch' in INCHES you should add with the halyard.)
Try the additional halyard strain, then see if other 'anomalies' are present before you make any decisions. Sometimes you need to add MORE halyard strain if the boltrope HAS developed a lot of 'shrink' ... if the shrinkage is too great to correct with a winch; then, you need a new sail or a sailmaker to 'adjust'.
If you do buy a new sail, get a steel tape measure that is longer than the sail luff... measure and RECORD that luff length and then youll know when that boltrope needs to be eased in the future.
ALSO.... when getting a new sail with a boltrope, ask the sailmaker to apply extra length of boltrope ... and 'store it' at the top/head of the sail (on the 'headboard'). Then, if you need to ease, that extra length is already 'stored' and such a job then becomes very fast and very economical (also ... then an easy DIY project using waxed sail twine, a sailmakers needle and sewing palm).
Add that extra halyard strain and measure that 'tack angle' ....... .
No other 'faults' that I can see from the 'pic'.
Not to worry, probably 99% of all those who 'cruise' dont know how much to 'raise' a mainsail or other boltroped sail. They usually 'just get it up' and never stretch out the 'preload' to the sails 'design dimension'.
Next time out, count the number of boats that have 'droopey' aft ends of their booms - never stretched out the boltrope!!!!! 99% !!!!!
hope this helps.
