Another key is to have gauges on the boat for backstay, halyard and lead positions, so you can repeat your settings. These can be as simple as tapes with numbers on the deck, or a batten with numbers next to the backstay ram.

No. When sailing on a reach, particularly on a boat with in-line spreaders, the backstay is used primarily to set the fore and aft position of the rig, in order to control the helm. This effect will be less if your boat has swept- back spreaders than with spreaders that are in-line with mast. Also, as the main moves away from the centerline, fore and aft mast bend does less to flatten the draft of the mainsail, and the outhaul does more to flatten the sail, particularly the bottom third.

Yes, but.... After the main is eased, the boom is no longer above the traveller, and then easing the vang is the only way to ease the trim in the top of the main, particularly when you are reaching in puffy conditions and need to de-power in the puffs.

@Andrew Parkes ;) But seriously - than You once again :)))

Pull traveller to windward, opens the slot between main and jib. Then ease the mainsheet to twist off.

Think about spending a few guilders to get a hydraulic backstay adjuster with integral pump, so you can adjust the headstay tension and mast bend with one control, which will make a huge difference in making your sails more efficient.

Choose from the following, as best you can: - boom vang on (if you have one) - pull the main in even tighter, move traveler to windward (if you have one) - move blocks on the jib track forward (if you have a track). Start with the lazy side, then tack when convenient and get the other side - tighten the outhaul (even sunfish have these, if rigged for racing)...tough to do on a bigger boat in the middle of a race. You'll probably have to wait until a downwind leg or maybe even do it between races. (if you have an extra crew member, they might be able to do this in the middle of a tack while the main briefly luffs) - ease the jib an inch at a time until main sail shape looks right. you may have to fall off ever so slightly as you do this, but you'll get a lot more speed to make up for the pointing loss

Pretty sure it's north sails trim simulator, it's about 10$

The apple and android apps appear to be gone. I downloaded the pc version (free) from the north sails website, downloads section.

Flatter but with more twist

also drops the head of the sail to leeward - depowering

@@yachticus, if your shrouds are tensioned correctly, backstay tension will only increase fore and aft mast bend. This may ease the leach slightly as the masthead moves aft, so be ready to bring in the sheet when you pump the backstay.

Increasing backstay Tension increases mast bend on many boats. This moves the luff further away from the leach of the sail, which in turn reduces the depth of the sail. Increasing backstay pressure also reduces headstay sag, which has a similar effect on the headsail.