What a difference sail-trim makes!

[Babylon]

Incredible to have doubled our boat speed today just by tweaking the sails!

I've never given it too much thought - having a heavy long-keeler with no concession to racing whatsoever - but I managed to get our boat speed up in pretty light airs from 1.5-2.0kts up to 3.5-4.0kts just by a few adjustments:

* traveller up to windward
* eased main and heads'l halyards a tad
* eased clew outhaul
* sailed full-and-by rather than pinching the last few degrees

Carrying the ebb down the western Solent from Lepe towards Yarmouth, we no doubt benefitted from lee-bowing the tide (ie the south-west-going tide added to what little inherent wind there was from the south-west).

What more could I have done to improve our performance (aside from fitting a different anchor to our CQR - not getting drawn into that one - or fitting a feathering prop - done - or having a clean bottom - also done)?

 

[Rivers & creeks]

That looks a useful checklist, I'll borrow it!

Taking weight off the boat is another idea, I read a knowledgeable post here a while back saying that a 10% increase in load requires a 25% increase in power. We took that to heart and unloaded 2 estate cars full of unnecessary stuff from the boat. I say unnecessary but naturally all gear I carry is absolutely vital

 

[Lakesailor]

I would guess the estate cars were really slowing down your boat.

 

[rotrax]

Hi, We took delivery of our pride and joy May 2009.We are still finding out how to get the best out of her,especialy in light conditions.She is also a heavy long keeled yacht.Our masthead and boom are marked with tape-I have assumed to give the previous owners optimum positions for main halyard and outhaul tension. Like you I have found a little less tension is benificial.Sailing free is best-pinching kills boatspeed dramaticaly.Centreing the boom with the traveler gives about 5 degrees better to windward when close hauled. What she really likes is 20 knts. on the beam and full sail-she takes off like a rocket. Trouble is with sailing you have too much or too little wind and mostly from the wrong direction. Still, on the days when its right its wonderful!

 

[Rivers & creeks]

I would guess the estate cars were really slowing down your boat.

And boy did they take up space

 

[NUTMEG]

Son + book

Since getting new sails for Alex over the winter my crew (middle son) has become a bit of a sail trim guru. Where before he sat at the tiller with a grin on his face all day, he now spends all his time staring wildly at the plethora of tell tails, constantly tweaks halyard tension and jiggles the jib sheet sliders. And guess what... We go faster. With a clean bottom we regularly hit hull speed now, without the engine either!

Only down side is that I spend all the time steering and no longer have time to chill out drinking tea and watching the world go by.

 

[Blueboatman]

re Babylon,
Whilst I don't have a fancy propellor, I did fit for about the same money an Asymmetric spinnaker which in light airs is simply the single bestest ever contributor to boat speed. Makes all the difference. Awesome, forgiving and nimble!
By the way ( 'tis a heavy, laden cruising boat with lots of spare sails and stuff etc) I have two full batten mains in very good shape, and a 'normal' short batten main with one full batten at the top, and it is my growing suspicion after a year of trying it that the full batten mains are no faster to windward at all, at the end of the day.
There, I may have just saved you a grand, and some weight aloft !

 

[Bosun Higgs]

You are asking for a short summary of what every racer takes years to learn and in my case never to make it!

The key is sail shape. The controls for the genoa are halyard tension, sheet tension and sheet angle. But you cant generalise too much about the sail shape yopu want - what will do for winds of 3/4 kn will not do for full sail and 20kn. For light winds you want the sail full so that the point of max curve is in the middle so the halyard will be slacker, maybe even horizontal wrinkles at the luff, and the top of the sail will be a bit more in than the middle to allow for updraught. In strong winds you harden the halyard to move draught forwards and if necessary move the car to let the top blow off.

Similar with the main but you have more toys.

Got to go. Suggest some reading. But these tweeks are important - even amongst racers who are trying the speed difference of identical boats can be 15 to 20% soi just imagine what speeds you get when you arent trying at all. And yes - speed or sailing efficiently does matter. Its so much more fun.

 

[Searush]

Many tubby cruisers like mine sail with the sheets too hard in & lose their drive. Most will just start the engine. I was shown (by Stuart Quarrie in a race) to feel for the lightest breeze with a wet finger (yes, honest) turn the boat at right angles to the breeze & let the sails out to 45deg, just holding them to shape.

Slowly, your boat will gather way, as she does so sheet in a tiny bit at a time to keep the shape in the sails, she will pick up a little more speed & you can gently start to turn towards the course you want (lets assume upwind). The idea is to use the apparrent wind gained from forward motion to help drive you forward. If you get it right, you may well end up at 35deg to teh apparent wind but maybe 60deg off the true wind.

This is where Twister Kens's ability to tack thro 35 deg off the wind gets somewhat harder! Cos if you are using the apparent wind well, you will only be tacking thro 100-120deg.

 

[Bosun Higgs]

Part 2 - the mainsail

Once you have the genoa trimmed its time to adjust the main. Again the position of the draught matters and in light winds you are aiming to have that mid sail to give power whilst in heavier winds ( anything that allows you to make hull speed) you want to bring it forward to 1/3. The prime control for this is the halyard but you adjust the outhaul so that the shape is similar all the way down except when hard pressed when you want the top to blow off. Adjust the mainsheet so that the top batten of the sail is parallel to the boom, and then leave the sheet alone to windward, adjusting angle of attack by the track. The main should just be beginning to, lift a little at the luff with the leach telltales flying just free. Heavier winds let the top blow off by tightening the backstay.

No doubt Flaming could do a far better job of explaining and probably correct me into the bargain. Apologies if I am teaching granny by the way.

 

[flaming]

No doubt Flaming could do a far better job of explaining and probably correct me into the bargain. Apologies if I am teaching granny by the way.

Seemed pretty spot on to me! It's a pretty common sight to see cruising boats failing to make headway in the light with everything pinned in tight.

This imortalised by one of our crew. "We're slow, someone ease something!" Which always seems to work, pretty much regardless of what is eased!

 

[Marsupial]

all of the above PLUS get a rigger to set the mast up properly you will sail faster.

 

[Allan]

all of the above PLUS get a rigger to set the mast up properly you will sail faster.

As I have said on here before, when I bought my boat I did not expect much in terms of sailing ability. After a year I had the rigging set up. It was like sailing a different boat! By far the best £30 I have spent on the boat. I think it can take up to an hour per day off my passage times.
Allan

 

[Keen_Ed]

When in doubt, let it out.

 

[gunman]

I have to say (and I am ashamed to say) that I am guilty of pinning everything in too tight.

I am hoping to change my ways though, this thread has inspired me.

 

[Twister_Ken]

More tips from the top...

In light airs:

Get some weight on the leeward rail to induce heel and help the sails 'fall' into their aerofoil shape.

Do everything very gently - don't shake the boat or the sails.

Never use more than a few degrees of rudder. When you've built up speed ghosting the last thing you want to do is brake with the rudder.

Try and avoid sailing into wash. It'll cost you a knot or three.

Look assiduously for good tide. Avoid bad tide even if it means creeping over the shallows.

Keep a good lookout for new wind - it's out there somewhere.

 

[Flying Penguin]

Babylon,

Like yourself, I've been experimenting with trying to get the best trim I can each time out and I found the following books really helpful:

Illustrated Sail & Rig Tuning (ISBN 9781898660675)
http://www.dedekam.com/sailtrim.html - Clear book with lots and lots of good diagrams, small enough to carry in the cockpit if the weather isn't too rough!

North U TRIM (ISBN 9780972436113)
http://www.northu.com/nu/NU_catalog.taf?_function=list&category=21&flash=5 - Bit more of a thorough bedtime read, but so far it's been very helpful.

Cheers,

Jamie

 

[gandy]

In very light wind I find it helps to tighten the outhaul and get the sail really flat. That was particularly true with our Wayfarer that had full race control lines so you could make a change and immediately feel the effect. Another tweak was to raise the boom a little to increase the twist.

 

[Bosun Higgs]

Never use more than a few degrees of rudder. When you've built up speed ghosting the last thing you want to do is brake with the rudder.
.

There are all sorts of other rules about tacking on windshifts and getting clear air, but the rudder one is very significant in two ways. First is never to just ram the rudder over when tacking - it acts like a brake, you lose far more speed and can take ages to recover it. The second is to get an idea of what tiller or wheel movement corresponds to 5 degrees of rudder, and if you find yourself holding on more than that 5 degrees going to windward either let off the top of the sails, harden the backstay etc or reef. Again the rudder is beginning to act as a brake.

Only learned this thanks to the forum this winter and have been astounded how much difference it made. My previous habit was to hang on to sail, toe rail under, 20 degrees of wheel on and wondering why we werent going faster! Just look at the turbulent wake behind you and the power you are wasting

 

[flaming]

And if you get all keen and start flying a spinnaker or cruising chute in "ghosting" conditions, if you want to get the most out of it turn the autohelm off and take the helm.

Then (assuming you want to go downwind) head up until the apparent wind is on the beam and let the boat accelerate. As it does, the apparent wind will go forward and you can slowly bear away, whilst keeping the apprent wind on the beam. If you bear away too much the chute will suddeny collapse and you'll grind to a halt in an "apparent wind crash".
So then you'll find yourself sailing in a series of gentle S curves, bearing away in the little puffs, and heading up in the lulls. In cruising mode it's quite easy to do this with the kite sheet cleated and just steering to the wind.

Then gybe and do the same on the other tack.

Throughout all this remember that the main is very much secondary now, and your first thought when trimming it has to be not to choke the flow off the back of the kite. Don't be afraid to oversheet it, but make sure the kicker is eased to help the flow at the top.