How to choose between a Flat Earth sail or a Falcon sail

In this blog I will elaborate on the differences between the Flat Earth sail and the Falcon sail. Roughly speaking, Flat Earth is very forgiving and therefore a little slow, but suitable for every paddlesailor in strong wind, up to force 6, if necessary, on large water with waves of roughly one and a half meters. Falcon is faster in all winds, so great for recreational paddlesailors who want a relaxed day out sailing. But in force 5 to 6, the Falcon is a lightning-fast Arabian thoroughbred. Exciting for experienced paddle sailors who need a kick, less recommended for beginners due to the greater heeling forces on a beam course. So it is wise to look honestly into the mirror and ask yourself what kind of paddler you are before making a choice.

To get an idea here's a YouTube video of Patrick Forrester, the owner of Falcon Sails. Looks like a downwind force 4 or 5.. The wind seems to blow not as hard, but his own forward speed gives the optical illusion of calm waters. Now and then he shoots sideways to half wind to keep an eye on his fellow sailors. Wow… Is that something for you or rather not? 

https://youtu.be/ysVTtX4H8B0

Here's the Flat Earth sail in even a stiffer wind and a little more tricky course on close reaching since the heeling force increases even more. Nevertheless the kayak stays upright, thanks to the sail and the seasoned kayaker. Now that's typical for a Flat Earth sail: relatively smooth paddlesailing in harsh conditions but also not quite as giddy and fast as a Falcon sail. 

And here's an example of my own Falcon sail in a super light breeze of force 2 or three. Despite the lack of wind, I make a decent speed already. This would not be the case with a Flat Earth sail. I would've had to make a couple of extra paddlestrokes.

Let's take a look at the differences in the design of the two sails to understand and appreciate the different performances.

Twist

An important characteristic of a good sail is the degree of twist, or spiral shape. A sail is not a flat piece of cloth, but is slightly twisted. The lowest part of the sail along the boom is not as far out as the top of the sail. This creates a certain spiral shape in the sail. This happens in part by itself because only the bottom with the boom is attached to the sheet, while the top of the sail hangs loose and can therefore turn a little away from the wind. For another part, sailmakers cut the lines of the sewn together sailpanels in such a way that extra twist is added. But why is that spiral shape necessary?

Unfortunately, sailors do not have to deal with just one wind direction. At first glance they do. For example, if you are sailing at a beam course with the wind coming in perpendiculair, the wind will be perpendicular to the boat. That is simple. But yes, the boat itself also moves forward. This has a significant effect on the angle of the wind hitting your boat. Suppose you have a wind vane at the top. It will flutter exactly 90 degrees outward when the kayak is stationary. But as the boat picks up speed, the vane will also move a little backward. From the sailors point of view the wind suddenly seems to be coming a little from the front when he looks at the vane or feels the wind on his face. We call this false image the 'apparent wind'. The actual wind, of course, still comes from the far left or right.

The problem with this is that the beam wind usually blows harder at the top of the sail than at the bottom, where the waves often disturb the wind a bit. The effect of your own forward speed is therefore less at the top, because the hard, unhindered beam wind still predominates there. Down below the effect of the forward speed is somewhat greater because the wind cannot blow freely there. So in your cockpit the wind seems to shift forward as you move along. More than at the top. So .... the sail at the bottom should also be sheeted in a bit more - as if you were paddlesailing a bit upwind. The top stays loose because the true, unblocked wind is still perpendiculair to the kayak And voilá, there is the need for a sail with the right twist to adjust the sail to the two different windangles

An almost 150 years old Dutch tjalk with a raised stern. The boom is sheeted in tight while the gaff top swirls out quite a bit, resulting in a clearly visible twist. Photo: Molenaar Sailmakers

Twist is also important for kayak sails, although the difference in wind direction above and below is much smaller. But there's another important reason for twist in a kayaksail.  Due to the spiral in the sail some of the wind will turn upwards and disappear over the top. This is called windspill which is very pleasant in strong winds. Thanks to the twist, the heeling force can be limited.

Flat Earth has based its entire corporate philosophy on this idea. A Flat Earth sail, originally developed on the rough Tasman Sea off Australia, is ideally suited for strong winds. Most of the wind flies up by itself and is then gone. The first models had a lot of twist, later on it was reduced to normal proportions. I believe that the Falcon sail has a little less spiraling-off effect. The sail is a standard triangle with the top fairly close to the mast as opposed to a Flat Earth with battens that keep the sail at the top much further back and therefor easier to turn away from the wind. 

 

An old model Flat Earth sail with a mindblowing twist of 21 degrees difference between the top and the boom. The wind is released quckly.  

A newer model Flat Earth with only 12 degrees twist. It holds on to the wind a bit more.

Another notable difference between Flat Earth and Falcon is that the Flat Earth sail has an even curvature when viewed from above. It seems as if the makers have come up with a circle and have taken a piece from it.

Falcon is much more like an airplane wing (see 'Sailing for dummies'). The deepest point or camber is mainly directly behind the mast and then flares out slightly to the rear. This creates a suction behind the sail that greatly aids in the forward drive. Almost all sails in the world have that aircraft profile.

Now you may understand the basic philosophy of Falcon Sails. This sail is choosen for power (and quality). Flat Earth has choosen for simplicity and ease of use for beginners. The even curvature in the Flat Earth sail is almost automatically created by the sewn-in flexible sprit that holds out the top of the sail. This keeps the sail low with less heeling force, while still providing a reasonable square surface. The result of a sewn-in batten however, is that the aircraft wing shape is difficult to accomplish. A Flat Earth sail has probably considerably less suction at the back side, I suspect. This also helps in limiting the heeling force. Very nice in strong winds, but less advantageous in lighter winds.

Rig and price

The rig of the two sails differ quite a bit but the quality is comparible so I don't want to go into this. You should neither. The key question is wether you want speed and/or stability in rough winds. 

The two sails do not differ much in price. A complete set of Falcon (1 square meter sail plus all accessories) costs $ 545 A slightly larger 1.4 square meter sail with larger rig: $ 575 A separate sail costs $ 145 The larger sail $ 175 - There also seems to be a smaller Falcon sail of 0.7 square meters.

In my experience it is possible to make your own rig, but not cheaper. And designing and sewing a sail yourself is just as expensive as ordering one, but it is fun to do if you don't dread a lot of work. See my blog 'Make your own sail' for this. As a beginner, I wouldn't venture into it and just buy a sail with the rigging. See also www.falconsails.com

A Flat Earth type Trade Wind of 0.8 square meters complete with accessories costs 500 euros, via importer for the Netherlands Axel Schoevers (www.zeekajak.nl). The sails come from England, so hurry up with ordering because the price could go up after Brexit settles down.

Both suppliers may be susceptible to a quatum discount if, for example, ten people of a kayakclub order a sail in one deal. 

Across the raging Tasman Sea, the precursors to Flat Earth

The first generation of modern paddle sailors were rather intrepid types with the urge to take advantage of the wind on big waves and long crossings on the Tasman Sea. Here's an ancient YouTube video from the late 1990s. These Aussies still have a stepped mast (through the deck) just in front of the cockpit and regular tent or tarp cloth as a sail. A sewn-in batten is already there, just like with the current Flat Earth sails. This batten keeps the sail at the top leach pointing up, creating sufficient surface while the sail remains low, which is good to prevent too much heeling. 

The disadvantage of these first generation sails is that they were probably less able to sail upwind. It was Mick McRob who perfected his mates' sails into today's Flat Earth models: slightly smaller (0.8 square metres), better cut to get close upwind and the mast far forward on a pivoting baseplate, out of the way of all paddle movements and yet controled from the cockpit with an uphaul line in case of an emergency. It can be lowered within a second an stowed under a bungee. Nowadays a good kayak sail in Australia is often mandatory during large crossings, as are all other safety equipment. 

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I apologize for the over-the-top music of Mendelssohn in the background.

Sudden gybe on a downwind run

The guys from Paddling Fool in Finland are on a downwind run with their Sail Dog sail, a clone of the 1 square meter Flat Earth sail. All goes well, until the sail gybes from left to right uncontrolably. What is going on? Very simple: the sail is still in the position for a beam wind so it is about half way sheeted in. A down wind can fairly easy creep up around and behind the sail causing it to swing in the other direction.

Normally a sudden gibe isn't such a problem. After all, the sail is far forward so a boom swinging over cannot hit anything. The sudden pull is quite gentile with a normal Flat Earth sail of 0.8 square meters, provided it is sheeted out far enough so the force is directed forward. Yet this 1 square meter sail is a bit different. The paddler is very bothered by it. A sail sheeted in quite a way on a down wind run causes a lot of tippyness since some of the force not only moves forward but also sideways. 

The solution is of course simple. The paddler lets the sheet out a little more till the boom and sail is almost perpendicular to the kayak. Now the pushing force in the sail is straight forward, not sideways any more and the inbalance disappears, The chance of gybing is a lot less and the speed also increases. See this movieclip, from 3.05 min. 

Ongewenst gijpen

An unbalanced kayak will turn upwind really fast

Here is an example of what happens if a kayak is not properly loaded. This kayak sailor in Finland thought he could get away with eight kilos more weight in the bow than in the stern. Bad luck for him. His kayak is on a downwind or quarterly wind run but keeps turning upwind because the high stern takes considerably more wind. More important, the stern is lifted out of the water a little but enough to lose it's grip and become susceptible to a side ways drift. 

He dropped his rudder all the way down as compensation, but it didn't help much. He just loses speed because of the drag around the rudder.  With just a skeg down it would have been even worse.

In short, kayaking with a poorly balanced boat is a disaster. A few kilos difference between front and rear is still manageable, but eight kilos difference is apparently too much.

Here it is:

https://www.youtube.com/watch?v=tqFOIY9qE5w

Falcon paddlesailors go up- and downwind

Two kayakers with a Falcon sail on eastern Lake Erie, USA, approach the tip of one of the Bass Islands. First they paddle straight against the wind to make enough 'height' for a close haul course to the island tip. The last part is on a downwind run, flying towards the harbor and sandy shore.

It's nice to see how they quickly throw the sail up in nice waves after a few tiring kilometers only paddling straight into the wind. 

Speedtest Sea Dog Sail (= Flat Earth)

Example of a Sea Dog Kayak Sail, more or less a clone of the Flat Earth sail. A short crossing in Finland (Archipelageo Natural Park), somewhere between upwind and half wind. Average speed 7.9 km/h, with a top speed of 13.4 km/h. Without really paddling along. Hold on!

Courtesy of Paddling Fools Production. 

Paddling Fools, speed run

Circumnavigating isle of Texel: very little paddlesailing

A circumnavigation of Texel is quite an achievement. Since my fitness was near zero during Easter 2019, I decided to get some support from my Flat Earth sail. A helping hand is never lost. The trip with five fellow kayakers, all member of Never Dry in Rotterdam (Marianne, Erik, Iede, Jan) and Chris from Nijmegen went very well, but I was only able to paddlesail for 15 percent of the time. The wind wasn't really cooperating. Sometimes too much headwinds, but more often from good directions but too weak.

ebb current

In view of the tide, it was decided to depart from Den Helder on April 20 at noon and to kayak via the western side along the North Sea to campsite Robbenjager in De Cocksdorp, about 34 kilometers. The ebb current pulled us smoothly through the Marsdiep under an indigo sky that faded into an equally blue sea. I immediately set up the sail because the wind was east-north-east. So almost on a beam course I paddled a bit, but the wind was only force 2 or 3 so it wasn't much. Beyond the Noorderhaaks, the divine ebb tide soon diminished. Once north along the beach with dogs barking and children playing, we were on our own. But the wind was blowing a little harder here, despite the lee of the dunes, so I was able to take a lot of advantage from the sail in the meantime. I could do with half the paddle strokes my fellow kayakers made, paddling about forty degrees close haul. That was nice. Also this time I noticed how easily you can get quite a bit of speed from only a few paddle strokes, despite the tight upwind course of about 40 degrees. I did hear 'hey, you lazy pig' every now and then, but I'm used to that now

Fun ended

Unfortunately, all fun ended as we continued on because the Texel coast is not straight up north as a ruler but gradually bends to the east. So the further we went, the more upwind I had to paddle. It was pretty much over near the beach dwelling De Koog. I lowered my sail and continued just paddling. After a break at beachpost 16 and another one at the Slufter, things got serious with the wind. It picked up further and now was right against us. According to fellow sailor Iede, this was because the eastern wind at the head of Texel curles more or less around the sanddunes in a direction coming from the north. The last kilometers to the tip (Eierlandse Gat) were indeed quite a challenge. Especially for me, as an undertrained sea kayaker on longer distances. My buddy Iede had to give me some encouragement, as I got a little anxious not knowing how rough it would be between Texel and Vlieland. As a child, countless islanders warned me to stay away from the Amelander Gat and other gaps between all islands with raging currents.

Once past the tip, we were caught by the now-reversed current that pulled us into the gap. My goodness, that was a beautiful sight. A pylon type buoy six meters high lay almost flat on its side groaning and grunting by the supercurrent. Behind this pylon a seething mass of water drew a deep pit. I shot right past it at the speed of a biker. The tide was now against the eastern wind, so we were bobbing on through the steep waves. After about ten minutes we moved onto the beach at De Cocksdorp, where a grueling climb up against the dunes followed with fully packed kayaks, just to find our camp spot. 

Vlieland

The next day the most sporty people did a half round of Vlieland, which was cut short because Chris was not feeling well and returned under supervision. On the way Jan shot a beautiful picture of a seal chasing the group.

I wisely stayed at the campsite to recuperate, but Erik asked if I would go with 'a walk'. Ah, why not? What started out as a nice promenade through the dunes in my sandals, eventually became a death march of more than twenty kilometers along the beach, the Slufter, the polders, the new residential areas far outside De Cocksdorp, just a detour to a supermarket, a hot snack and a liter of beer on a dull terrace and then off to the campsite. After seven hours of marching at Erik's pace and four blisters, I collapsed on a borrowed air mattress because I had forgotten mine. After that I don't remember anything.

Retreat

More dead than alive, I started the retreat on day three. Back across the dunes with full kayaks with the carts dangling loosely at the bottom. Iede showed the route on the laminated maps one last time: an impossible route way out on the Waddenzee through narrow shallow waters among sandbars just hidden under a high tide. From my kayak all you could see was ocean so following a complicated path onto the horizon seemed illogical. But we knew it was a matter of one or two hours before the sandbars would pop up, terminating our trip. Finally we approached a larger passages, the infamous Texelstroom that has been in use for centuries. Here we caught a low tide back to Texel with great speed of about three miles an hour of current. The whole detour which you can clearly see on the map took us about two extra hours. In my mind I heard myself ask the question why we couldn't just paddle straight along the dike on the east of Texel. A stupid question, I suspected. The Waddenzee is well known for it tides, riptides, shallow waters en steep waves. Paddlesailing in a straight course is almost impossible.

Going south and way out in the Waddenzee to avoid shallow waters.

Anyway, it was little consolation after going so far out east, that I could raise my sail again going back south-west on a quarterly course. However, no spectacular paddle sailing on this day either. Although wind force four to five was predicted with waves of one meter which led to a quick prayer during breakfast, but it would be limited to windforce two, at most three, all day long. With that gentle breeze at my back, I soon went so fast that I didn't feel any wind at all.

During our arrival at the carparking in navytown Den Helder it became clear how extraordinairy that was. Though almost no wind at sea, the predicted windforce did occur right above land and Texel. A divine hand had draped a gentle bubble over our position at sea. I guess my eary morning prayers did help. But please, dear Lord, a little bit of wind would have been nicer. Thank you.

Thanks to Jan (photos) and Iede for the organization, especially all calculations of the tides and the correct departure times. It was a fun puzzle.