Sails

Wind Speed and Sea State

The Beaufort Scale is used as a method for judging wind speeds based on sea states. Wind drives the formation of waves, so the stronger the wind, the larger the seas will be.  

The problem with this is waves take time to form, and in the beginning, the sea state will be relatively calm compared to the photos of the sea states that correspond to each Beaufort level.  

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Here, we see a view of the ocean on what looks like a mildly choppy day. There are scattered whitecaps and bits of spray flying through the air. The winds were sustained at 50 knots with gusts of 83 knots.  

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Since the winds cropped up out of nowhere, the seas did not have time to mature into the towering walls that you would expect with these winds. 

These conditions are Force 10 and should produce waves of 29-41 feet! These waves look no taller than 6-10 feet.

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Why the discrepancy? Well, a few factors can come into play here. First is duration of the wind. Second is depth of the water.  

The water in the picture is about 400 feet deep close to the shore and 4000 feet deep just a bit past the shore. Deep water allows waves to mature into their full size without breaking, as the water is deep enough to support the wave and allow it to move without interruption.  

The second is the duration of the wind. At the time of this photo, the winds had only been at this level for about an hour. To fully mature into the giants of the Beaufort scale, they would need at least a full day.  

If you find yourself out at sea in horrible conditions like these bit feel like putting off reefing down to your storm sails “because the seas don’t look all that bad”, consider how hard it would be to reef once they pick up! 

Reef before the storm hits they way you are safe and prepared for the winds and seas to come! 

Alternative to a Tack Horn

Part of reefing is getting the tack cringle onto the tack horn, it’s how you secure the tack of the sail while reefing! How else would you do it? 

The struggle with this old method is that the horns can hook and poke holes in the luff of your sail as you raise the sail, and you have to get your tack cringle over the horn in foul weather. When you combine the situation of high winds, a flapping sail, and a pitching deck; suddenly getting a little ring over a little horn doesn’t sound like a fun idea. 

Alternatives exist, where a strap with rings on the ends will be sewn through the cringle, so that you can simply place the ring on the strap over the horn, as the strap is easier to manage than the stiff luff of the sail. 

All this got me thinking about alternatives to this debacle. What about taking a very strong dyneema line and simply tying the tack in place? 

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I used a 7mm length of SK-78 dyneema with an alpine butterfly hitch tied in the middle to give the tack line an appropriate purchase point. The line simply passes through the tack webbing, through the bight, back through the tack webbing and back through the bight, then through the webbing one more time to tie off just below the alpine butterfly hitch.

Having a long length of line means that I can reach the tack webbing with ease from a distance, and the purchase system lets me pull the tack down tightly.  The dyneema is very strong and able to hold the forces of the sail with ease.

It is imperative that the tack line run down and forward to keep the forces mostly vertical on the luff of the sail. If the tack line does not have a forward component to it’s pull, the luff of the sail will be pulled aft with no countering and it will rip your luff off the luff track.

What we do is tie the tack line, tension the halyard with the winch, then set the clew line for the reef. This way, the clew line is acting on an already tensioned and set tack, resulting in a stable reef setup with zero risk to the sail during sail raising. 

Weather Helm and Lee Helm

Sailboats have two rudders steering them, not just one!

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The first one is the one everyone thinks of when you they hear the word “rudder”. This is the appendage that hangs off the back of the yacht that is controlled by the wheel or tiller and is the primary method for controlling a yachts direction.  

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The second one is exclusive to sailboats, as powerboats do not have this second rudder, the sails. As wind hits the sails and gives the sailboat power to drive through the waves, it also influences the direction the yacht will go as it moves through the waves. 

If the sails are all at the back of the yacht, the wind will hit them and push the back of the yacht downwind and the bow upwind. This is known as weather helm. 

If the sails are all at the front of the yacht, the wind will hit them and push the front of the yacht downwind and the stern of the yacht upwind. This is known as lee helm. 

Having the right balance of sails, front and back, is necessary to cause the yacht to be pushed evenly and to avoid this urge to rotate. 

The urge caused by the wind can be felt in the helm, and can lead to crew fatigue if you are counting on the rudder to compensate for unbalanced sails.  When the yacht wants to turn upwind, simply turning the helm to leeward will make the yacht sail in a straight line, but you will have conflicting events happening. The sails want it to turn upwind while the rudder is dragging through the water trying to turn the yacht back to leeward. The result is these forces will cancel out and the yacht will sail straight! But the cost of these conflicting forces will be loss of speed as the rudder and sails need to cancel out their opposing forces instead of all moving forward in harmony.

Trimming each sail to optimum performance by following the tell tales will give you maximum performance out of each sail, but not optimum performance out of the entire system. If you sacrifice pure performance and instead focus on minimizing weather and lee helm, you will actually sail faster and with less drag.

Thinking of the sails as a second rudder, almost as an air rudder, will be advantageous in your seamanship abilities. Instead of setting the sails for power, and then adjusting your course with the rudder, it would behoove you to set the sails based on the winds and point of sail you wish to be on, then fine tune your heading with the rudder. Thinking of the sails as your primary steering method, more of a macro rudder, and your rudder as a fine tuning steering method, more of a micro rudder, will let you sail most efficiently and effortlessly. 

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Controlling Weather Helm while on a Run

Weather helm is a phenomenon where the force on the sails wants to turn the yacht up and into the wind. This is caused by having the Center of Effort (CE) of a sail aft of the Center of Lateral Resistance (CLR) of the underwater profile. Balancing the sails is simply the act of playing around with the CE to get it to be directly in line with the CLR.

If the CE is ahead of the CLR, the boat will have lee helm and will want to turn downwind. If the CE is aft of the CLR, the boat will have weather helm and will want to turn upwind. Only when the CE and CLR are directly over each other will the sailboat be balanced and sail straight, not venturing upwind or downwind.

Balancing the sails is not the same as trimming the sails for maximum performance. A lot of time, you will need to have your sail working at less than peak performance to properly balance out the whole setup. This is easy when you are sailing on a beam reach, where all the forces acting on the yacht are coming from the side, but what about on a run?

To be on a run, you need to ease your mainsail all the way out so that it can act as a large drag to the apparent wind and be pulled along, likewise pulling your yacht along with it. Here is where it gets tricky.

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As you ease your sail out, the CE of the sail will not only move forward, which will help give you lee helm and pull your yacht downwind, but it will also move the CE laterally and outboard. This long and very powerful lever arm, also known as your boom, will act on the mast and try to turn your yacht opposite of the direction you have eased the sail. In this case, with the boom eased to port, the force on the sail will try to turn the yacht to starboard. This may feel and act like weather helm, but it is not caused by the aft movement of the CE, instead it is caused by the leverage of the mainsail held out by the boom.

The further outboard the clew of the sail is, the longer the lever arm is that is acting on the yacht, and more leverage the sail will have to turn the yacht in the opposite direction. 

Your options here are simple, either you can move the clew further in or not ease the sail as far. Moving the clew inboard is effective at reducing this torquing. This can be achieved by either reefing the sail or simply not easing the clew past the beam of the boat. Obviously, these options seem counterintuitive as the apparent wind while on a run is less than the true wind; more sail would seem logical!

Instead of reefing, and dealing with the boom on a run, an alternative is to raise the trysail. 

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The trysail has no boom, so the foot will curl more easily when the sail is eased. As you ease the sail, the clew will tend to move directly forward from the sheeting point, and as such will stay inboard of the beam of the yacht. 

The sail is also smaller but when eased will fill up and provide a great amount of drive downwind. Since the sail will curl up, the majority of the sail will be right along the mast, in the middle of the rig, further keeping the CE close to the midline of the yacht. 

Being a small sail, it also won’t block the wind from reaching your headsail. This will increase the headsails effectiveness which will then aid in keeping the bow of the ship pointed downwind.  

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Having a trysail up on a wonderful day may not seem intuitive, but it really does help take out the weather helm while sailing downwind. This will balance your sailplan and let your yacht sail more balanced towards your downwind destination.

Dedicated Trysail Track

A trysail is a small storm sail that is flown in place of your mainsail. It usually lives deep in a sail locker stuffed into a bag. Here it typically remains for the entire life of your yacht.

The idea behind a trysail is that should the winds pick up to severe speeds, you can drop your mainsail and raise the trysail. This takes all the stress off your mainsail and puts it solely on a dedicated and purpose built sail.

The problem in this narrative is that the sail is stuffed away where it is forgotten, and therefore, seldom used. In a storm, the last thing you want to do is root through a locker, pull out a sail, remove the mainsail, attach it to the luff, and then raise it. When a storm hits, you want to make your main smaller and get back to the cockpit as quickly as you can!

Having a dedicated track for the trysail allows you to set it up before you leave port so that should the situation arise, it is ready to go.

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We flake and then ball up our trysail at the foot of the mast, where it remains laying in wait for the moment we might need it. We have the starboard sheet tied to the clew, so all we need to do is attach the port sheet once the mainsail has been lowered; and its dedicated halyard already attached.

When we need the sail in a hurry, we just drop the main and raise the trysail. The starboard sheet is set, so worst case scenario where we don’t have time to attach the port sheet before raising, we can sail on port tack. The clew of the trysail is low enough that I can easily reach it to tie on the port sheet after it has been raised without reaching overboard or far off the deck (I’m tall though).

With the trysail setup like this, we find that we use it very often, which makes our blue water passages very relaxing and safe, since we can don the storm sails just as easily as we could raise our working sails.