Sheet In or Sheet Out?

Posted by Director of Education on May 25, 2015 under About NauticEd, Bareboat Charter, Crew, Skipper | Comments are off for this article


If you like what we have done here, please LIKE it on facebook – thanks it really helps us grow. While you are at it please follow/LIKE our facebook page over there ——> we post fun cool stuff.

Here are some great examples of how you can read the tell-tales and instantly know what to do. Look at each example and decide what you should be doing.

In the examples, click the selection box you think best on the image.

In this example above you are on the starboard side of the boat since the boat is going from left to right. Also, you see the green tell-tale over the top of the red. Red is on port side of the boat. The green tell-tale is on this side of the window and on the starboard side of the boat. And one more observation is required and that is that the genoa is on the other side of the mast and thus on the port side of the boat.

Given all the deductions from above, the wind must be coming from your right hand and flowing into the computer screen to the left. The green tell-tale is being starved of air whilst you can see the red has plenty as it is flowing smoothly. This means there is turbulent air on the starboard side of the boat.

If you sheet in (tighten up the sails by pulling on the post side working jib sheet) slightly this will allow the incident wind to flow more smoothly on the this side of the sail. The green tell-tale will then start flying backwards smoothly. We show this concept of smooth vs turbulent airflow using moving arrows inside our FREE Basic Sail Trim Course.

i.e. in the above – Sheet in!

If you are struggling with this  – simply take our FREE Basic Sail Trim course. It will make you more knowledgeable than most sailors out there.

FREE Basic Sail Trim Course

FREE Basic Sail Trim Course

or get it on iPad ($a buck .99)

 

Here are some more examples to test your knowledge.

So what do you think? Are you ready to take our FREE Basic Sail Trim Course now?

Go there now – what the heck – throw caution, timidity and fear to the wind!

 

FREE GUIDE:  Learn how to gain a sailing certification with NauticEd

Head Up or Bear Away?

Posted by Director of Education on May 24, 2015 under About NauticEd, Bareboat Charter, Crew, Skipper | Comments are off for this article


If you like what we have done here, please LIKE it on facebook – thanks it really helps us grow. While you are at it please follow/LIKE our facebook page over there ——> we post fun cool stuff.

Here are some great examples of how you can read the tell-tales and instantly know what to do. Look at each example and decide what you should be doing.

In the examples, click the selection box you think best on the image.

In this example above you are on the port side of the boat since the boat is going from right to left. Also, you see the red tell-tale over the top of the green. Red is on port side of the boat. The green tell-tale is on the other side of the window and the starboard side of the boat. And one more observation is required and that is that the genoa is on the other side of the mast and thus on the starboard side of the boat.

Given all the deductions from above, the wind must be coming from your left hand and flowing into the computer screen to the right. The green tell-tale is being starved of air whilst you can see the red has plenty as it is flowing smoothly. This means there is turbulent air on the starboard side of the boat.

If you turn the boat into the wind slightly this will allow the incident wind to flow more smoothly on the other side of the sail. The green tell-tale will then start flying backwards smoothly. We show this concept of smooth vs turbulent airflow using moving arrows inside our FREE Basic Sail Trim Course.

i.e. in the above – HEAD UP!

If you are struggling with this  – simply take our FREE Basic Sail Trim course. It will make you more knowledgeable than most sailors out there.

FREE Basic Sail Trim Course

FREE Basic Sail Trim Course

or get it on iPad ($a buck .99)

 

Here are some more examples to test your knowledge.

So what do you think? Are you ready to take our FREE Basic Sail Trim Course now?

Go there now – what the heck – throw caution, timidity and fear to the wind!

 

FREE GUIDE:  Learn how to gain a sailing certification with NauticEd
 

3 Reasons to Twist Your Sail Out

Posted by Director of Education on April 30, 2014 under Bareboat Charter, Crew, Skipper | Comments are off for this article

If you like this post please “LIKE” it or g+1 it – it really helps us grow and is a good exchange for the value we provide here.

NauticEd is the World’s Most Advanced Sailing Education and Sailing Certification Program.

Perfecting Sail Trim and Twist

Here are three reasons you should be twisting out the sail towards the top of the mast

  1.  Get rid of excessive heeling
  2. Match the wind at the top of the sail to the wind gradient
  3. Drum Roll … The most important … Change heeling force into forward force.

(1)   Getting rid of excessive healing forces.

I’ve written on this topic a few times mostly because it is an important fundamental topic of understanding the forces on a sail.

In a right triangle, a force applied evenly over the surface can be considered to act in one place. This place is called the Center of Pressure and is the geometric center of the right triangle and is 1/3rd of the way up the triangle. It is found by crisscrossing the corners and midpoints.

The propensity to heel is called the Heeling Moment and it is derived  from a multiplication of the wind force magnitude and the height of the Center of Pressure.

Thus, the heeling can be reduced by lowering the Center of Pressure. You can do this obviously by reefing but also by twisting out the top of the sail which changes the triangle shape.

 

Twisted mainsail lowers and moves the center of pressure forward

Twisted mainsail lowers and moves the center of pressure forward

This also has the added effect of moving the Center of Pressure forward which reduces your weather helm.

(2)   Match the wind at the top of the mast to wind gradient

Wind velocity at the surface is less than wind velocity at the top of the mast due to friction of the surface on the wind. This is called Wind Velocity Gradient. In addition there is another effect called Wind Shear which is due to coriolus effect dependent on the distance from the equator and if northern or southern hemisphere. This wind shear creates a different direction of wind at the top of the mast than at the boom height because the wind is seen to twist as it slows down.

When you combine Wind Velocity Gradient and boat velocity you also get different apparent wind directions on the sail. This is best described in detail in our free basic sail trim course.

Because of this effect the wind at the top of the mast is more from an aft direction. Said to be “more aft”.

 

Wind Velocity is different in speed and direction between surface and top of mast.

Wind Velocity is different in speed and direction between surface and top of mast.

When flying a sail then you already know to match the sail angle to the wind to make it most efficient. If the wind direction at the top of the mast is more aft the sail direction must change to be more let out moving up the mast. To achieve this you twist the sail out by allowing the aft of the boom to rise up. This loosens the leach of the sail and allows it to twist out at the top.

Adjust Sail angles up the mast to match apparent wind direction

Adjust Sail angles up the mast to match apparent wind direction

Control your leach tension via the boomvang. Keep in mind also that your mainsheet will also control leach tension as well. If your mainsheet is in tight, loosening the boomvang will have no effect. When you let out the mainsheet this will deliver the leach control to the boomvang. You can then use the traveler to re-center the boom.

 

(3)   Changing Heeling Force into Forward Force

This is not talked about much but it is the most important when thinking about making your boat go fast.

The force acting on the sail from the wind can be thought of as being approximately in the direction perpendicular to the battens.  As the sail is twisted out in going up the mast the force then shifts from sideways unwanted heeling force to desired forward driving force by the nature of its direction.

Twisting the Sail Changes Heeling Force to Forward Force

Twisting the Sail Changes Heeling Force to Forward Force

This then is very important. As you know, not only should you always have your sails let out as much as possible just before luffing to fly the sails efficiently but you should additionally be looking up the sail and adjusting twist as much as possible to translate the resultant force to be forward acting rather that sideways acting. Increase twist until upper sail luffing occurs then tighten slightly.

As with point 2 above use the boomvang, the mainsheet and traveler as your controls.

For more information on Sail Trim, take out Free Basic Sail Trim Course and our advanced Sail Trim Course.

Get started on your Sailing Certification with NauticEd today. We really focus on teaching you all the aspects of sailing. This kind of stuff makes you look like a hero in front of your crew.

Please socially share this article below.

Sail Trim Finesse

Posted by Director of Education on March 28, 2014 under About NauticEd, Bareboat Charter, Crew, Skipper | Comments are off for this article

Back Winded Mainsail

Back Winded Mainsail

We are on a close haul at 30 degrees to the wind. I want you to check out this photo and have a good look at the shape of the mainsail. The photo is taken on the windward side of the boat.

Look at the black seam line. Good or Bad?

Well is is doing exactly what I wanted it to do. The front of the sail is curved in on itself – but why?

On this day we had about 15 knots of wind and I had not yet reefed the mainsail BUT we were over powered. So I eased the mainsail traveller out a little but keeping the head sail in tight. This back pressured  the leading leeward edge of the mainsail causing it to create an “S” shape. This pressure comes from back eddies at the forward leeward side of the mainsail and from pressure gathering between the main and the headsail pushing the leading edge to windward. I do this often prior to reefing. Effectively it reefs the sail. If you look, only the trailing last half of the main is powered up making the sail act almost exactly like it is reefed. BIG NOTE: the sail is not luffing. It is constantly in this shape if you’ve got it adjusted just right.

 

Back Winded Mainsail diagram

Back Winded Mainsail diagram

This effect can be seen in the image below. While I am the first one to recommend reefing the sails, this little trick can help you out when riding just on the edge. Try it next time you’re out.

Want more information on Sail Trim?

Take the NauticEd SailTrim Course!

Sail Trim Course

Sail Trim Course

 

 

Sailing by the Luff

Posted by Director of Education on November 24, 2012 under Skipper | Comments are off for this article

This question was posed to us on our NauticEd Sailing facebook page

QUESTION:
Well My Uncle invited us out to see the tall ships on parade in Long beach harbor… but we sailed outside the breakwater, then headed back in. At one point I got behind the helm of the boat to get the feel of steering the boat. And my Uncle tells me to “Steer by the Luff of the sail” I was a little bewildered by this since I’ve never heard the term before. So, I hope this will be explained here!

NAUTICED COMMENT about SAILING BY THE LUFF:
When I learned to fly – the instructor’s first introduction for me to flying was to teach me to fly the plane straight and level.  He did not explain any thing else about flying speed and stalling  or turning or direction or anything – it was two full sessions on straight and level flying. The same needs to be done with learning to sail. Teaching from the outset to sail the luff of the sail is a bit bewildering for the new student. The best way to start some one new at the helm is to get them to point exactly at a point on land and have them continue to sail to that point. After a while a new point can be sailed to then a new point. It’s important to develop “straight and level” sailing with a new student. Sailing by the luff of the sail is too advanced for a first timer. Sailing the luff of the sail is a combination of sail set and boat heading to have the sail set at it’s most efficient setting. But with out understanding all the wind flow dynamics first – how can a new sailor be expected to understand this. The theory needs to be shown on paper – or better yet using animated graphics. NauticEd’s basic sail trim course shows the dynamics of wind flow over the sail. It’s some thing that can not be efficiently taught on a boat on the water. You might send the basic sail trim course link on our site to your uncle.  Not to take anything away from him at all – it’s awesome that he gave you the helm. I think if you understood a little of the theory first – you would have grasped the practical goings on very quickly.

Please take our Free Sailing Course on Basic Sail Trim and tell as many people about it as possible especially people with boats – if they could have people go through this course before they took them sailing it would help a lot.

Do YOUR Job

Posted by Director of Education on May 14, 2011 under Crew, Skipper | Be the First to Comment

Yesterday we were out racing in our local sailing regatta. At the end of any regatta race we always have a debriefing on what we could have done better. Turns out this one works especially well in our work lives as well and so that was the topic of conversation over a few beers afterward.

We were approaching a downwind mark and setting up the strategy for a reach to the next mark. Unfortunately we were not leading the pack but at least we could see what every one else was doing. They were all dowsing their spinakers and reaching with their genoas for the outer mark. One lone boat however kept up their spinaker but things were starting to get busy as we closed in on the mark and so we didn’t see him. (Turns out the skipper on that boat was the 80 yr old father of the famous Chris Dickson – one of New Zealand’s top sailors having skippered in 5 America’s cup challenges).

So up went the genoa, down came the spinaker and round the mark we went. Once around the mark we just couldn’t keep up speed with the pack. And as we were seeing, the wind had shifted a little so that keeping up the spinaker for the reach would have been advantageous. The order came to get the spinaker back up.

Thus starts the lesson:

Getting the spinaker back up again immediately after a take down is out of the ordinary. It was quickly packed in the launch bag and passed upstairs and set into place on the bow pulpit. The spinaker sheets were quickly re run. The pole was clipped into the port guy and raised with the topping lift to clip onto the mast. The halyard was bought forward to be clipped onto the head of the spinaker (top grommet of the spinaker). BUT the spinaker head was no where to be found. Luke, who was working the foredeck was yelling back to the spinaker packer that he couldn’t find the spinaker head. All eyes fell on Luke as he frantically dug through the launch bag to find the top of the sail.

Now if if you’ve ever worked with a spinaker, you’ll know that it must be packed perfectly like a parachute in order for it to launch properly. Each edge of the chute must be “chased” from one point to the next as it is packed. The clew, tack and head must all be positioned in the launch bag properly. It not the results can be disastrous.

As eyes  stayed on Luke hoping and willing him to find the spinaker head, focus was lost. The helms person was watching Luke, The mainsail trimmer was watching Luke. The headsail trimmer was watching Luke. Everyone was wanting to help Luke.

It was the skipper who pulled it all back together and called an end to the kafloffle that was going on. Spinaker efforts were abandoned and focus was back to everyone doing their jobs. By that time we’d lost incredibly valuable distance to the main part of the pack.

In reality, it only required one person to sort out the mess and the rest to just keep doing their jobs – trim and steer trim and steer. On a sailboat – you’re job is to race the race doing YOUR job. As a skipper your job is to keep everyone focused on their jobs and keep the big picture in play. Getting the spinaker up was not the big picture. Making the boat go fast was the big picture.

How can we make our business’s go fast?  What’s the big picture of your job? I know this – for a sail trimmer – the big picture is to keep all the tell tales flying – that’s it. And it’s not an insignificant task!

I recently experienced this myself again in the Rolex Regatta in St. Thomas last March. NauticEd and its adventure Partner Safe Passage sailing chartered an 80 ft Maxi race sailboat to compete in the series. For much of the race series I was working the mainsail. A dozen other NauticEd students joined us. The boat was awesome, huge, and the biggest I’d raced on. I found it incredibly hard to focus on my job. There was only one thing I could do when all hell was breaking lose at the bow of the boat. That job was to sail the mainsail.

At the start of one race, we had a 90 ft boat right next to us forcing us up to the start line. The job was to sail the mainsail not look at the paint job on the multimillion dollar boat 10 feet away and fear a crash. Just sail the mainsail!

NauticEd Students Racing in the Rolex Regatta

NauticEd Students Racing in the Rolex Regatta

One more example which we talk about in our bareboat charter bvi course. We were coming out of North Sound on Virgin Gorda in the BVI’s. Another catamaran had already exited and had turned back towards Virgin Gorda to head to wind to get the main sail up. As you may know, getting the mainsail up on a big cat is not an easy job and it was taking some time. All eyes were on the sail going up. No eyes were on Prickly Pear reef towards which the Catamaran was immanently going to hit. Had it not been for our horn blast and pointing, they surely would have grounded on a breaking nasty reef.

In this case the helms persons job was to keep the boat into wind and watch out for traffic.

So many analogies can be made between sailing and the corp world. What I’ve found is that through out a race (which takes about 2 hours) almost all the same issues come up in a 10 month project. You can see a very subtle secondary analogy in the example above. The 80 year veteran kept up his spinaker whist every one was taking theirs down. We had the advantage of observing that – but we didn’t because “things were getting too busy”. Hmmm, how’s that for a lesson in watching the competitive field.

It would be of incredible value if we could take our project team and run them through a sailboat race first before we start a project. Quick side note:  I’ve got 32 different exercises to be done on a sailboat depending on the required developmental strengths that a team needs. If anyone needs a experiential training program for their team let me know.

Regardless – next time you’re leading a team in a race regatta – make sure your team keeps focus on their own personal job.

 

Leeway and a Bottle of Rum

Posted by Director of Education on June 22, 2010 under Bareboat Charter, Coastal Navigation, Crew, Skipper | Be the First to Comment

Leeway is just one of those things that is a law of the universe that we have to put up with. It’s just like gravity. Still with gravity – the advantage is that it’s highly predictable. And so then is leeway.

Leeway is the sideways slip motion of our sailboat down wind from the pressure of wind against our boat and sails. It results in a course that is less than desirable.

Leeway Slips Your Boat Side Ways Down Wind

Leeway Slips Your Boat Side Ways Down Wind

Airplanes suffer from the same issue. When flying in a cross wind, the plane crabs (slide slips) downwind. The course becomes different from the heading.

Not accounting for leeway will have you sailing (or flying) in a fairly unnoticeable arc to get to the mark. To represent an example with a mark to the north and a westerly crosswind, here’s what happens; you aim for the mark at 000, your boat slips sideways to the west. Now your mark is at 359 but you don’t really notice it. After a few minutes your mark is at 358 still in noticed. Minutes later your heading is 355 then 350 etc. All because you keep aiming at the mark but you’re being pushed to the east by the wind. Your course over ground becomes an arc and is the long way around.

The prudent sailor will account for the leeway and sail a constant heading depending on their known leeway of say 350 for the example above. The sideways slip motion will deliver them to the mark in a straight and shortest line.

Now that we’re in the electronic age, navigators will plug in the destination to the gps. The autopilot which is cross talking to the gps takes care of the rest. The gps analyses the cross track (the boat’s distance away from a straight line to the mark) and feeds back to the autopilot the proper heading to minimize this in real time. Thus resulting in a straight course to the mark.

I’m doubt that during the Wednesday/Friday night beer can race such electronic methods are utilized. So I’m suggesting that to take line honors and win the bottle of rum at your club race by taking account of leeway.

Leeway is particularly more prevalent when you are sailing on a close haul or close reach and can be as much as 20 degrees depending on the wind conditions, water conditions, your sailboat design, your apparent angle with the wind and how your sails are set.

However, other than buying a new boat, the only thing that you have control over is the trim of your boat and sails.

Here’s a couple of general rules to follow:

  • Over sheeted sails cause more sideways force and thus sideways slip (leeway). Fly the telltales diligently.
  • Aim for a position to windward of the mark you’re trying to go around. The more you are sailing on an upwind course, the more the degrees upwind you should aim.
  • The higher the wind speed, the higher above the mark you should aim.
  • In general, on a close haul, allow 10-15 degrees. Adjust this less if the wind is light, more if the wind is strong. Reduce this amount linearly as you bare away from the wind.
  • Make sure your boat is trimmed with slight weather helm.

When doing serious navigation we absolutely must account for leeway and an excellent understanding of how your boat performs leeway wise is essential and how to solve for it once you know it. NauticEd developed an educational navigation video solving a leeway and current exercise at http://www.youtube.com/watch?v=1LQcFOGSJQs

Using a gps and a nice steady windy day, you can do a simple determination of your sailboat’s typical leeway.

(1)   Begin sailing on an angle slightly off a close haul direction and with a recognizable land marker dead ahead.

(2)   Measure your speed

(3)   Douse the sails and begin motoring at the same speed in exactly the same direction.

(4)   Take note of your gps course.

(5)   Deploy the sails and turn off the engine.

(6)   Continue to aim for the same point on land.

(7)   Now read out your gps course.

(8)   The difference in course angles will be your leeway

(9)   Repeat for different points of sail

(10)    Repeat for the opposite tack.

(11)     Repeat on different days with different wind strengths

Note that:

(a) this method is relatively immune from current because you have normalized it out by performing the motoring task.

(b) this method will not account for the leeway due to the hull of your boat presented to the wind.

We hope you enjoy your bottle of Rum!

Weather Helm Vs Lee Helm – What is it? How to use it?

Posted by Director of Education on June 16, 2010 under Crew, Skipper, weather | Read the First Comment

During the Americas’ Cup campaign in New Zealand in 2003, I saw one of the best explanations of this on a TV interview with the Greg Butterworth, the Tactician for the Alingi Team.

Most of us sort of understand the concept and we’ve been left with the answer of “Well – weather helm is better because it’s safer.” But few explanations go into how it gives your boat a sailing advantage.

The definition of weather helm and lee helm is simple and it is easy to remember which is which. If you have a tiller, weather helm is when you have to pull the tiller to weather (toward the wind) in order to keep the boat going in a straight line. Lee helm is when you push the tiller to lee (downwind) in order to keep the boat going in a straight line. We’ve probably all felt this slight pressure required on the tiller when underway.

Your boat can be tuned to give weather helm or lee helm. Rake the mast forward  and you move the center of effort of the wind forward which causes your boat to want to turn downwind. Rake the mast back and you move the center of effort of the wind back causing your boat to want to go upwind to weather.

When your boat gets rounded up – you just experienced massive weather helm. No matter how much you pull the tiller to weather, you can’t stop the boat going to weather. Dumping the main sail moves the center of effort forward thus reducing the weather helm.

The basic perception of weather helm being safer comes from this effect: if you let go of the tiller, it will automatically go to center because of the water flowing over the rudder and because the rudder is pivoted at its leading edge. Now there is no rudder force to counter the desire of the boat to turn up wind to weather so the boat does exactly that. It turns to weather and rounds up slowing the boat down and reducing forces on the rig. Conversely, lee helm  means that if you let the tiller go the boat will turn away from the wind, heel over more increase forces on the rig.

So from a safety point, weather helm is good. BUT there is another advantage that we’re not generally taught. Holding the tiller to weather means that there is a slight pressure on the rudder to windward. This actually MOVES THE BOAT TO WINDWARD as it slices through the water. And we all know what that means, race advantage!

The Weather Helm Advantage

The Weather Helm Advantage

The illustration shows how the water pressure from weather helm creates a sideways force on the rudder tending to push the boat to weather.

Now Greg Butterworth went on to explain that there are other cool things you can do. One is to put a little trailing edge swinging control surface on the keel.

The illustration below shows this effect too. For us pilots, this is much like a trim tab on a wing of a small airplane. The trim tab creates the ability to adjust the lift at that point on the aircraft and thus create a balance of forces. The issue to remember here is that you’d need to trim the tab the other way when you tack over.

A control surface on the keel

A control surface on the keel

So there you have it. While we’ve all been understanding the lifting effects of the wind over the sail, the other fluid that we’ve ignored is the water under the boat and how we can gain lift from it too.

Next time you’re out sailing on a nice steady 10 knot breeze, come up on a close haul, trim the sails perfectly so that all your tell tails are flying smoothly. Then notice what pressure you’ve got on the helm. Note that if you’ve got a wheel, weather helm will be a tendency to apply downwind turning pressure on the wheel (which is the same as pulling a tiller upwind right?). Ideally you should have slight weather helm. If not, you should probably not jump right in and start raking your mast back. Talk to a mast tuning specialist in your area first.

Stopping Rounding Up Dead in it’s Tracks

Posted by Grant Headifen on June 8, 2010 under Crew, Skipper | 7 Comments to Read

Rounding up is caused by many factors. One is too much wind and force aloft which tends to heel the boat over. This reduces the amount of rudder in the water and thus the rudder’s effectiveness. Another factor in rounding up is the center of pressure of wind on the sails is too far aft which then pushes the aft of the boat downwind and thus the front of the boat up wind.

The NauticEd SailTrim clinic discusses this topic and so what we wanted to do was test it out for sure. So last weekend we took out a friend’s Beneteau 373 to test out an anti-round up theory. Read on to find out the results of our experiment.

First though, we must first understand wind shear. The phenomenon of wind shear is pretty easy. Wind moves faster at the top of the mast than is does at the water level because the stationary water slows the down the wind in close proximity.

Secondly,  consider the concept of true wind vs apparent wind. Which is best understood by imagining driving your car in a cross wind with your hand out the window of the car.   At stand still you would feel the wind coming from the side of the car. The faster you go, the more you feel the wind coming from the front of the car. But when a gust of wind comes (which is just an increase in true wind speed) then you would feel the wind shift back more to the side. When relating this to a sailboat, if your boat was standing still, the wind at the top of the mast would be the same apparent direction as at the cockpit level albeit, faster (from the wind shear phenomenon). However as your boat picks up in speed the apparent wind moves forward BUT because of wind shear it shifts forward less at the top of the mast. IE at the top of the mast the wind tends more to the direction of true wind direction because the true wind speed is higher.  Thus at the top of the mast the true wind is more aft than apparent wind. Aft means it is coming from a direction further towards the back of the boat. Get it?

So – whether you get it or not. The fact is: at the top of the mast the wind is higher in speed and more aft than at the cockpit level.

Figure A and B show the boat speed, true wind and apparent wind vectors for cockpit level and top of the mast. Obviously in both cases, the boat speed vector must be the same. The true wind vector is obviously the same direction but due to wind shear it is longer (faster) at the top of the mast. This results then in the apparent wind direction being more aft. IE in this case from 135 deg to 125 deg.

Wind shear and apparent wind phenomenom

Wind shear and apparent wind phenomenom

Thirdly, you should understand that if a sail is sheeted in to tight it creates more heel. This then is exactly what is happening at the top of the mast.  Even though at the bottom of the sail you may have perfectly trimmed the sail, the top of the sail is sheeted in too tight against higher wind speed. No wonder you’re getting excessive heeling. And excessive heeling creates round ups.

This is now quite a revelation! It means that the top of the main needs to be “out” further than the bottom of the sail for it to operate efficiently. This  is usually indicated by the top telltale. Often the leeward telltale will be stalling at the top of the sail. Especially in high wind because of the phenomena above.

The top of the mainsail needs to go further out so that the starboard telltale can fly smoothly

The top of the mainsail needs to go further out so that the starboard telltale can fly smoothly

Thus the top of the mainsail needs to be let out further so that the leeward telltale can fly smoothly. This is commonly referred to as twisting the sail out at the top. Except people believe you are just spilling out (wasting) the wind at the top. Not quite so now, as you’ve just learned. Twisting out the top of the sail is letting the top of the sail fly according to the direction of wind it is feeling.

In the illustration, you can see the top telltale on the downwind side is fluttering. If you let out the main at the top, the wind can reattach to the sail on the leeward side and the telltale will fly smoothly reducing the force aloft.

Understanding all the above. How do we stop rounding up?

Option one: Obviously the first and safe option in higher winds is to reef the sail.

Option two: Let out the traveler which is what most people do when hit by a gust. Just so long as you realize what you’ve done is not twisted the top of the sail out – all you’ve done is let out the mainsail from top to bottom and thus depower the mainsail. This reduces the force aloft and thus the heel. It also moves the center of effort of wind on the sails forward which reduces tendency to round up. The trouble is that you spend all day fighting gusts with still quite a few involuntary round-ups.

Option three: Let out on the mainsheet. Here again you’ve depowered the entire mainsail to handle the gust. Still, it works.

Option four: Permanently reduce the force aloft by letting out further on the mainsail and tightening up on the traveler. The trick here is to bring the mainsail bottom back in again using the traveler. Yes, bring the traveler to windward up past the center point. Most sailors are reluctant to do this because they’ve been taught that it detaches the wind on the leeward side. But not when you’ve let out the mainsheet. In effect, by letting out on the mainsheet, you’ve allowed the boom to rise up and the leech of the sail to slacken. This creates the desired twist at the top and allows the top of the sail to fly according to its apparent direction. At the same time, the bottom of the sail can fly according to its apparent direction.

By trimming the traveler and mainsheet together  you can manage the twist at the top of the sail as desired yet still keep power on the bottom of the mainsail. Keeping power on the bottom of the mainsail keeps your speed up which also increases the effectiveness of the rudder. Increasing the effectiveness of the rudder means it can hold more against any turning effect created by the shifting of center of pressure backwards. Wow – see how it is all connected.

What happened on our 15 knot gusty sailing day? Well, not one round up.

So to summarize, the sailing lesson here is when in higher winds bring the traveler up and sheet out the main. You’ll also need to release the boom vang a little. Letting the boom vang out allows the boom to rise which loosens the leech (trailing edge) of the sail and allows the top part to “twist out”.

This and many other finer sail trim concepts are discussed in NauticEd’s Sail Trim Clinic.

NED – Interactive Sailing Instructor

Posted by Grant Headifen on July 16, 2009 under Crew, Skipper | Be the First to Comment

NED is an interactive online sailing instructor developed by NauticEd – The World’s Most Advanced Online Sailing School.

The educational sailing training tool uses interactive flash technology to show novice sailors how to set the sail trim according to the wind direction which maximizes the efficiency of the sails. The tool teaches in about 5 minutes that which sometimes takes hours on a sailboat. Sailing Instructors worldwide are adopting this tool as the standard for teaching basic sail trim.

To play with NED below – READ THIS FIRST.

There are 4 main controls:
Mainsail: Sheet-in and sheet-out (pull the main sail in or let it out)
Headsail: Sheet-in and sheet-out
Helm: Turn to port or starboard
Wind Speed: Click the red triangle to change the speed of the wind

IMPORTANT: The center dial represents a true wind meter on a sailboat. All windmeters have the boat pointing straight up because you are standing behind the wind meter when on a boat. On NED however, there is one slight difference to simulate the boat turning when you depress the helm button. The boat will turn but will flick back up to its proper position when the helm button is released. You will notice then that the wind direction and the HDG (compass heading) has appropriately changed according to how much you turned the sailboat.

As you turn you’ll notice that the speed of the boat changes as with the efficiency slider bar across the bottom. the trick is to maximize the speed and efficiency for the wind direction.

Go ahead and try it out. Here are some exercises – each time set the sails to maximize the sailboat speed.

  • Turn the boat to 120 degrees off the wind on Starboard (wind from the right hand side of the boat). Notice the screen will announce the point of sail “Broad Reach”
  • Turn the boat to 90 degrees off the wind on starboard (“Beam reach”)
  • Now change the wind speed to 20 knots and notice the change in boat speed.
  • Tack the boat through the wind to 30 degrees on port (“Close Haul”)
  • Turn the boat to 80 degrees onport
  • Now go to 180 degrees (wind directly behind)
  • You’ll see the sails gybe over when you go to about 170 degrees.

Play with NED as much as you like until you really feel you have the hang of the sail set. You’ll discover that this is almost exactly what you’ll need to be doing when out sailing. See below for a few tips about sailing with a windmeter. Once you’ve mastered NED – you can play with the Advanced sailing Instructor version on the NauticEd Online Sailing School website.


Access to NED is provided FREE to the world courtesy of NauticEd.org

Windmeters are great because you don’t have to keep looking at the top of the mast (and around the bimini) to find the exact direction of the wind. Therefore learning to sail with a windmeter is a necessary skill. When sailing with a windmeter here is a sailing tip which we cover in the NauticEd Skipper Course.

One issue that appears most often with new sailors is focusing too much attention on the electronic wind meter or the wind direction indicator (the pointy arrow thing at the top of the mast). Imagine driving down the highway looking at your speedometer for more than 10 seconds. You would surely have an accident. Now relate this to looking at your wind instruments. As with a speedometer in a car, you only need to look at them for long enough to gain the information it is telling you (IE check wind instruments for about 1 second every 10 seconds). The rest of the time your eyes should be up out of the boat and looking at your surroundings and the horizon taking note of which tree, house, cloud, island etc that you are sailing towards to hold a straight course. You make your course corrections when looking out of the boat then you check the wind instruments to see if you’re back on the desired wind angle. If not then lift your head out of the boat again and make a new course correction. In this manner you can judge exactly how much your boat is turning.

If you make course corrections while looking at the wind instruments you will tend to over shoot every time. So the Sailing Technique is to keep your head out of the boat and check the windmeter in short glaces. Think about trying to drive down a highway using a compass only and stay in a straight line or make a 90 degree turn using a compass. Not really possible or practical yet the tendency to do this when sailing is high. Rid your self of any such habit from day 1.

People ask “well what if you’re on the open ocean and there are no objects to point at”. Don’t worry – by the time you get to the open ocean you’ll have the “FEEL”.

This discussion is equally similar when you give the helm over to a novice. The best thing to do to a novice is to start them out by having them aim at something so that they can get used to sailing in a straight line using small 1/4 turn max corrections on the wheel. Trying to explain to someone who has never taken the wheel about the wind indicators is pretty pointless.

As you’re becoming more confident in your sailing abilities you can test your self out on a clear steady wind day by looking at the wake you’re leaving and ensuring it is in a straight line. This will tell you if you’re tending to slightly over steer and keeping focused on the job at hand.

The previous discussion was taken from the NauticEd Skipper Course.