Mainsail Trim

[mhinnc]

I don't know how long it's been on the boat, as we've only had it about 2 1/2 years. No doubt past its prime, but able to help get the boat up to hull speed in the right conditions.


This sail shape issue has only been noticed late in this past season, so something with the rigging must have been inadvertently changed to cause it. Until we decide if a new(er) boat is in the offing this sail will have to suffice.


All the good advice is much appreciated! Thanks especially GordMay for the diagram and links.

[HeinSdL]

Jib halyard is begging for some tension too! There are two issues with what I see, firstly the shape of the jib will be... baggy and secondly, in a gust, the localized pulling on the jib where it enters the furler profile may cause it to be pulled out completely which would be unhelpful.

Edit: apologies, this was obviously already mentioned.

[TrentePieds]

You have an excellent set-up wrongly used :-)!

The clue is in the "tension crease" that runs from above the reefing cringle (where the reinforcement patches are on the luff of the sail, diagonally aft and down to a point on your boom that isn't shown in your pic. Anytime you see a tension crease like that, you know you are doing something wrong!

No sense in being anything other than systematic in coming to grips with this "problem". Bring the sail all the way down and slip the halyard off the headboard of the sail. Attach the "zero" end of a 50 foot measuring tape to the halyard. Now hoist the tape so it is chock-a-block with the sheave in the mast crane and note (in your maintenance log) the PRECISE reading of the tape at the upper side of the boom. Now knock off a foot from that measure. That reduced measure should be the length of your luff. If the luff of you sail is longer than that, it is wrongly dimensioned for the boat, and should be modified or, in the worst of cases, the sail should be replaced.

Now refer to the diagram GordMay so kindly gave you. The red line at the bottom is the fall of the topping lift shown in red aft of the leach of the sail. In the diagram it is very properly led to the cockpit.

Whenever you hoist or reef the sail, ALWAYS begin by starting the sheet and the vang below the boom, then take up six inches or a foot on the topping lift so the weight of the boom is borne by the gooseneck and the topping lift and there is NO tension on the sail itself.

To reef, bring her head to the eye of the wind, start your sheet and vang, take up your topping lift, start your halyard and haul in you reefing lines (first or second as required). Now belay the halyard with a bit of tension on the luff. It should have been marked at the appropriate point where it comes to its cleat. Now start the topping lift so the boom-end is borne by the sail rather than the topping lift. Now fall 'er off to the desired point of sail and trim up your sheet and vang as required. Now tidy up any lines lying about.

In a C&C30 properly set up the entire procedure should take just about a minute from beginning to end, i.e., so little time that she won't even have time to fall her head off the wind before you are ready to fall off deliberately and let the sail draw again.

For now, that will get you off to a good start. You do NOT have to sail "to perfection" until you've got these fundamentals under your belt. When you have that, we can begin to discuss the use of Cunninghams and other devises used to perfect the sail trim.

Do not be misled by suggestions from people who use roller furling. Doing so requires RADICALLY different techniques!

Bonne chance!

TrentePieds

[MicHughV]

Some boats have the boom on a sliding track. Hoist the mainsail (and the boom with it) to the top of the mast, then pull the boom down to remove the crease. The distance the boom may travel might be 10-12" or so.
The sketch that Gord posted is another way to accomplish the same thing.

Today's boat have a tendency to lead all lines back to the cockpit, which can be confusing as to what line does what??

[MicHughV]

Another thing to point out. The boom is likely to have a topping lift attached to the arse end of the boom. If this tension is not relieved by loosening it, the main will not be able to set properly.
Some boats use a hydraulic vang to accomplish this.
The topping lift arrangement varies from boat to boat, so hard to say at this point, what to do, but keep it in mind.

[Bowdrie]

Originally Posted by mhinnc

It may simply be the luff is too long for the mast.

I think a couple of posts alluded to it, but is the sail a "real" sail for a C&C 30?
Would a sailmaker put-on the C&C emblem if he made a replacement sail?
Might not be of any concern, but in the pictures/diagrams of mast/mainsail we always see the boom precisely at a right angle to the mast.
In real life this is not as common as one may think.

[Searles]

The use of a Cunningham tackle for mainsail trim ,even to pull down the first reef is common ,have even use one on a headsail on a furler to get the tension wright .⚓️⛵️

[TrentePieds]

Refer again to mhinnc's picture.

The gooseneck is CLEARLY fixed on the mast and cannot play any part in tensioning the luff. The sail HAS to have the right dimensions, and that means that when the luff is snug, the headboard must be six inches or a foot SHORT of the halyard shackle going chock-a-block. Ignoring that requirement just makes life difficult!

It is also clear from the photo that our friend needs to let the clew outhaul run. Take the weight of the boom-end by means of the topping lift and slack off the clew outhaul leaving it slack while you deal with the luff. Once you've got the luff under control you can set the clew outhaul again and start the topping lift.

TENSIONING the luff is a separate issue. In a 30-footer with the work being done at the mast, as it appears from the photo it is intended to be in THIS boat, it can be done easily by simply "sweating up" the fall, before belaying it. Back when this boat was rigged, i.e. before roller furling, there was often a snatch block on the fall that helped to take the last few pounds of tension. That is not the case here. The fitting through which the fall runs is merely a fairlead to prevent to fall from blowing out of reach when slack.

The tack is not correctly positioned. This can be rectified easily by simply taking a light line through the tack cringle and around the mast so that the luff becomes straight from head to foot and securing this frapping with a simple square knot on the foreside of the mast. It needs to be inside all running gear, of course.

You will see that there is a light line rove through small cringles on the luff. This device is for drawing the luff into position when the sail is reefed. This is why there is a set of cringles at each of the reef points. These cringles are fitted as PAIRS! For the upper pair, immediately below the upper patches, i.e. the SECOND reef point, the light line is correctly rove through them and through the eye on the slug in the mast cove. You will perceive that when that line is tautened, the luff will be pulled in towards the mast, as it must be. The line is NOT correctly rove through cringles and slug at the lower patches, i.e. the FIRST reef point, and it would appear from the way it IS rove (or rather NOT rove!) that our friend does not understand the function of this device.

We can come back to how to rig the reefing gear for this boat later, once we've sorted out the basic sail-set.

TP

[donradcliffe]

Take a good look at the mainsails in this picture. Each one of the sails cost more than your boat, and they are being trimmed by the absolute best crews money can buy.

https://www.52superseries.com/the-52...es/tp52-class/

Now tell me again about horizontal wrinkles at the lower luff.

[campbdon]

There is no photo in the first post but if I may add a thought. If the luff is too long for the mast then a sailmaker can lop off a few inches off the head and reattach the headboard (or a new one). You'd only lose a few square inches of sail at the top by doing so.
I had this done to a previous sail and it worked fine

[mhinnc]

Appreciate all the info & advice. Thanks.