Finer Points of Sail Trim for the Cruiser...

[barnakiel]

Originally Posted by mpc7002

Just to point out that this topic is "Finer Points of Sail Trim for the Cruiser..." not the "Finer Points of Sail Trim for the Racer..."

Yep. Some of us are sailors, some use the sails just for decoration. I would burn in 5 years the amount of diesel others burn in a week. Still, at at end of a passage, we met in the same lovely anchorages.

Life is good.
b.

[s/v Beth]

I agree with b. My biggest problem is keeping the diesel from getting bugs in it, cause I never use it enough. As far as trim. Keep me going at hull speed and you can make fun of my sails all day long. Up in the San Juans tide direction is as important as wind direction, and that changes so much I often have my sails out of trim. But we do our 40 km and still have time to enjoy the anchorage...

[s/v Jedi]

Sailors who never care about sail trim are the ones that get in trouble when the wind pipes up to gale conditions because then it becomes vital to trim correctly. It is then that they (or their wives) decide that motoring the sailboat is a better way and cheaper too, considering the cost of sails and their repairs. So we see them motoring and having a hard time while passing them rapidly under a reef or two, nicely flattened main & mizzen with some extra twist above, traveler in the right position etc. while having cocktails in the cockpit ;-)

cheers,
Nick.

[Jim D]

I have "issues" when I see boats with inadequate luff tension. It just ruins the look of everything, and I love the look of sailboats being well driven.

Oh, and having headsail lead blocks in the wrong position, and the leach or foot too loose: I simply say "Yuk".

Yep, I do like to trim sails.

[Bash]

you can trim for speed
you can trim for balance
you can trim for safety
you can trim for aesthetics.

[Hud3]

Or, you can trim to feed your OCD.

[sneuman]

Originally Posted by s/v Jedi

Sailors who never care about sail trim are the ones that get in trouble when the wind pipes up to gale conditions because then it becomes vital to trim correctly. It is then that they (or their wives) decide that motoring the sailboat is a better way and cheaper too, considering the cost of sails and their repairs. So we see them motoring and having a hard time while passing them rapidly under a reef or two, nicely flattened main & mizzen with some extra twist above, traveler in the right position etc. while having cocktails in the cockpit ;-)

cheers,
Nick.

Jedi - I don't disagree with you, really, but my point in posting the quote was to illustrate that the first sailor to do a non-stop single-handed circumnavigation (in a 30' boat!) through the southern latitudes, no less, expressed his barely passing knowledge of sail trim. I suspect he was being a bit on the modest, but nonetheless.

Now, I will admit that when you read his book, there are only a few occasions when he's going anything forward of the beam (between Oz and the Cape, where he was expecting southwesterlies and got easterlies instead. Naturally, he expressed hatred of that situation.

[zydecotoad]

I suspect that Knox Johnson was rather expressing his feelings about 'expert' yachtsman theorizing about sail trim. I doubt that the man did not have a very strong knowledge of practical sail trim.

[senormechanico]

Originally Posted by s/v Jedi

Sailors who never care about sail trim are the ones that get in trouble when the wind pipes up to gale conditions because then it becomes vital to trim correctly. It is then that they (or their wives) decide that motoring the sailboat is a better way and cheaper too, considering the cost of sails and their repairs. So we see them motoring and having a hard time while passing them rapidly under a reef or two, nicely flattened main & mizzen with some extra twist above, traveler in the right position etc. while having cocktails in the cockpit ;-)

cheers,
Nick.

LOLOL !! I know that feeling.
My wife thinks I'm being mean when I point at the motoring ones.

[senormechanico]

Originally Posted by Bash

you can trim for speed
you can trim for balance
you can trim for safety
you can trim for aesthetics.

And usually, they're all for the same good reason.

[nigel1]

nicely flattened main & mizzen with some extra twist above, traveler in the right position

Whats the best way to achieve this, to flatten the main its outhaul on all the way, halyard tight (dont have a cunningham), if the sheet is eased to give twist, should I also ease the vang??

[NormanMartin]

A couple of thoughts about managing twist:

In practice:
1. Attach telltales at the end of each batten pocket. They should be about 15 cm long, light in color, and made of a narrow (1 cm) piece of nylon fabric. If you have in-mast furling, attach the telltales to the leach of the sail near where battens would be.
2. Twist is correct when the leach tension is such that the telltales all fly/flutter straight back. If the telltale wraps around behind the sail, the leach tension is too tight. Release some of the tension.
3. Adjust twist with a combination of mainsheet and traveller position or with the vang. A...Sailing upwind, tension the main sheet and adjust the sail angle of incidence with the traveller until the telltales fly. If the telltales don't fly and the sail luffs, ease the sheet a little and traveller back to center since the leach is too tight.
B...The vang is used when the boom must be eased beyond the range of the traveller. On a broad reach, for example. On the wind, the vang has less "pull-down-power" than the mainsheet.

In theory:
A sail is analogous to a propellor blade. Propellor blades have twist. The tip rotates faster than the hub. Apparent wind angle is different at different distances from the hub. Wind at the surface is slower than wind aloft. hence the need to adjust the twist to match the variations in wind speed/apparent wind angle at different heights.

Nigel and all... I am doing some writing on this subject. If the foregoing seems to need "tweaking" for not being clear, your feedback will be welcome.

[nigel1]

Thanks Norman, thats cleared it for me.

[BubbleHeadMd]

Wow. I can't wait to get on the water this spring and be judged by my sails from a distance as I attempt to put theory to practice.

[s/v Jedi]

Hi Nigel,

You must have a Cunningham and I think that almost every sail has at least the grommet needed available (a foot or so above the tack of the sail). Just take a 2 meter piece of line, tie one end to your boom/fitting/reef-clew, take it through that grommet to the other side of the mast and put it onto the winch there. If you have both mast winches in use for halyards, you need to put a rope clutch on the mast for the jib halyard to you can use that winch. There's your Cunningham. When I reef, I use the same system at the reef point, instead of using the reef-hook.

The last thing that you need is also easily made yourself: you need some draft stripes in the sail. They allow you to see the draft at those positions. A sailmaker can supply you with the right tape for it, but for testing you can even use 3M blue masking tape (but take it off afterwards).
Now you're all setup. You have the halyard, cunningham, outhaul, leech tensioner (but don't worry too much if you don't have it), vang, traveler and sheet. Go and sail a course 60 degrees to true wind (about 40 degrees apparent), engage the AP, go to the mast and have the crew at the sheet and traveler control lines. Time to play!! Just try everything: a little more of this or no try that instead. Take at least an hour to work it out.
That evening, read a book on sail trim. Buy a small but excellent book (not a 1,000 page monster) like the book by Dedekam: Sail trim: "Illustrated Sail & Rig Tuning"
Don't read it before your day of playing because you need to experience that AHA!! moment. Next day, try it again with what you learned from the book. It will change your sailing career and the payback in comfort and speed is enormous (and you will become the guy that is going out for a sail when it's blowing 30 knots while the rest think you're crazy ;-)

cheers,
Nick.