Tuesday, February 08, 2011

Sea kayak sailing for non sailors!

Photo Ginni Callaghan Travels with Paddles.

I was delighted to read in his "Travels with Paddles" blog that the highly respected coach, Axel Schoevers from the Netherlands, has discovered Flat Earth Kayak Sails! In his enthusiastic write up of the sail he writes "The sail was reviewed in issue 22 of Ocean Paddler Magazine and that article didn't mention or even hint towards the, for me, most rewarding part of the sailing: tracking by edging!"

The first people I saw sailing sea kayaks here in Scotland were all experienced sailors or windsurfers but recently non sailors are discovering the delights of sailing a sea kayak. So I thought I would give a few pointers here to help those who are new to sailing, which might also explain why I did not mention controlling the track of a sailing kayak by edging in the OP article....

Photo Kari-Tek

As Flat Earth sails become more common, photos and videos are beginning to appear on the Internet, usually with the kayak being sailed with a lot of edge and the paddler in a trailing low brace position. Additionally, some videos show the application of frequent stern rudders to keep the kayak tracking straight. In contrast, Gnarly Dog's video shows his kayak sailing upright and the paddler still paddling!

In all the photos below, David and I are sailing with the kayak upright and as it was me who wrote the article in Ocean Paddler, why didn't I mention controlling the tracking with edging? By his own admission, Axel is not a sailor and as an expert kayaker, he is trying to use a kayaking technique to control what is now a sailing craft. In contrast, I have only been kayaking for 11 years but like David have been sailing for over 50 years (everything from 38foot yachts to windsurfers). Sea kayak sails are very small, about a third of the smallest windsurfer sail, and they operate close to the waves, where the airflow is disturbed, so they need to be sailed efficiently and this requires some understanding of sailing technique.
When sailing any craft, you want to keep the airflow running from the front of the sail (luff) to the back (leach). As soon as you lean (edge) a kayak downwind (to leeward) the airflow is disrupted and starts to run up the sail, as in the top two photos. If you lean into the wind (to windward) the wind tries to run down the sail and escape from the bottom. It takes a while for the proper airflow to reestablish and in doing so, the centre of effort in the sail is moving all over the place, further upsetting your trim and where you want to go!

Every time you edge (or lean) you will loose speed as you have stalled the normal airflow. If you maintain edge for any length of time, in your effort to hold a course, you are creating extra drag and cutting your speed. Since the main point of kayak sailing is to go faster, it helps if sail, skeg and hull configuration are as efficient as possible and are working with each other and not against each other.

So in sailing, you want to keep the rig as upright and steady as possible to keep the wind flowing aft across the sail. In a sailing kayak you steer a course by a combination of sail sheeting angle and skeg. You start with the right sheeting angle, which generally means that you let the sail out as far as possible, without allowing the wind to get round the leeward side of the luff. If you are not a sailor you can thread a piece of fine wool through the luff half way up the mast and about 15 cm back from the leading edge. When the sail is let too far out, the airflow will be going up, when just sheeted in enough, the airflow will start moving back and the telltale will be horizontal.

If you sheet out more than this, the centre of effort will move aft in the sail, if you sheet in more than this the centre of effort will move forward Incorrect sheeting will altering the balance between rig and skeg and make it more difficult to hold your desired course.

If you want to sail with the wind about 90 degrees to direction of travel (beam reaching), you trim the sail as above then adjust the skeg to maintain tracking in the right direction. Move the skeg up, if the bow of the kayak wants to go down wind, or move the skeg down if the bow of the kayak wants to go up wind. On both my Quest LV and Nordkapp LV, the balance is so sensitive that I move the skeg slider only a few mm at a time.

With practice you can even sail the Flat Earth rig upwind (at about 45 degrees off from the direction of the wind). You can only do this if you keep the kayak upright. If you edge the kayak, when close hauled to the wind, you will stall the sail and lose speed and then you will need to paddle further off the wind to get going again.

Watching some people new to kayak sailing in Scotland I can always spot the non sailors. The better kayakers try to maintain tracking by edging, those that do not have effective edge control end up using stern rudders.Every stern rudder slows you down, so its much better to get the sail/skeg trim right in the first place. It's all about balance and the kayaker now needs to think as a kayak sailor!

If you are sailing downwind, either broad reaching (wind 45 degrees behind) or running (wind behind) in waves then there is still a place for a quick use of edge or stern rudder to give just a momentary correction of direction. However, when the sail is correctly trimmed and set, it makes the kayak more directionally stable (even in waves) so you will find you need less stern rudder and edge than without a sail. In fresh winds in these conditions, you will be travelling much faster than without a sail and you will find that the kayak responds by turning a given amount after applying much less edge than you are used to. However, I like to use only a minimum of edge, to keep the sail steady with good airflow.

I only have a hand held camera so don't have any strong wind photos. Looking downwind the sea always looks as if there is less wind than there is, so I am putting some upwind shots in for comparison.

I was doing 14.4km/hr here without paddling, note how vertical the kayak and sail are. This is broad reaching and without the skeg, the kayak would have weather cocked strongly. I adjusted the skeg to hold my chosen direction but as I also carried on forward paddling (then my speed went up to 17.2 km/hr) I could also maintain direction by adjusting the power on each side.

This is broad reaching in a fresh wind, which is gusty. David keeps the kayak vertical and when the gust hits the design of the Flat Earth Sail allows the roach (top rear) of the sail to twist off, spilling wind and so not overpowering the kayak. In most conditions, you do not need to spill wind by leaning the kayak to leeward and supporting yourself using a trailing low brace (as in the second top photo). 

This was paddling up wind, just far enough so that we could bear off, put the sails up and cross to our destination close hauled, sailing as close to the wind as possible.

David and I are now setting off sailing close hauled, note the vertical kayaks. Sailing close hauled is the most tricky course in kayak sailing. We are in the process of adjusting the sails to our course. David has eased his sheet until the luff has just started to collapse with wind getting round behind the mast, then he will pull it in until the luff just fills. His sheeting angle will then be similar to mine. My bow is a few degrees closer to the wind than David's and the luff of my sail has started to collapse. I would lose speed if I pulled the sail in any tighter than this, so I will ease my skeg up a little to allow the bow to move away from the wind a couple of degrees to match David's heading. As we cross the loch, the wind direction will be changing slightly all the time, so we will be continually testing how high we can point into the wind without the sail stalling and losing speed.

David sailing close hauled when a gust has just hit him. Gusts have most heeling effect when sailing close hauled into the wind. However, David has resisted the temptation to lean the kayak to leeward and use a trailing low brace. He carries on forward paddling, note the kayak is vertical. In the gust, the mast has moved aft along the fore and aft line of the kayak. As the gust  hit him and the elastic in the fore stay, which holds the mast up and forward has stretched. Together with the cut of the sail, this allows the roach to twist off reducing the power and heeling effect of the sail. David is still travelling fast.

Another broad reach in a not very strong wind but I am doing 9.7km/hr (without paddling) as I am sailing efficiently. Note the vertical kayak. When I resumed paddling, I was doing 14.5 km/hr.

This is close hauled, I am pointing into the wind as high as I can without slowing down, I am about 45-50 degrees off the wind..  I would not sheet in any tighter than this in an effort to point a few degrees higher. I would slow down too much and also stretch the elastic in the fore stay pulling the mast back (as in the gust photo of David with the red and blue sail above). I have experimented with removing the fore stay elastic to allow a closer sheeting angle (without the mast raking back) but I found the rig was much less forgiving in gusts. The elastic also helps prevent gear getting trashed if you capsize in surf, especially near the beach....

Here there is a small swell, I paddle upwind first so that I can then bear off the wind, put the sail up and broad reach to my destination.

I am now broad reaching and sitting on a small swell exploiting its power. I have my skeg partially down to balance the sheeting angle of the sail. I am travelling at 16.5km/hr and am overtaking the swells. Normally my Nordkapp LV would not be very responsive to edging with the skeg down but at this speed things change and even small amounts of edging can change the direction of the kayak quite significantly. I never edge much more than this, certainly not as much as in the top two photos.

In this photo I have lifted my port edge and this would normally cause the bow to swing round to the left. However, when sailing at this speed in the Nordkapp LV and Quest LV, lifting the left edge causes the bow to go round to the right (this might not happen with all kayaks). I am sailing diagonally down the waves and in this case I feel I am just slipping off the back of the wave, so I am bearing off to pick up speed on a broader reach and hopefully stay on the wave. (At the same time I would normally paddle a little harder as well, but I was taking the photo!)

Broad reaching in waves is the fastest point of sea kayak sailing. So far, my maximum speed has been 24.7km/hr in a P&H Aleut Delphin, see video below.

This video shows how easy it is to launch and recover the Flat Earth sailing rig.

This video will hopefully give you some idea of how much fun kayak sailing can be in a force4/5 wind. It's stonkin' fun!

One problem when sailing in stronger winds is capsizing when launching the sail. The safest way to do this is to reduce the apparent wind acting on the kayak by paddling downwind as fast as you can. Launching with the sail on a dead run (with the wind directly behind you) can also be tricky as the full area of the sail is exposed and fills as soon as it is launched. The best solution is to paddle on a broad reach (wind blowing about 45 degrees from the stern). I mark my sheet so that I can see where to cleat it so that on a broad reach only the rear half of the sail fills with wind. The luff (front) is back winding with wind getting round the lee side of the mast (side away from the wind). This sail sheeting position allows the sail to spill wind.

Once I am travelling fast preferably surfing on a wave, I quickly pull the uphaul and cleat it to launch the sail. I put in another couple of paddle strokes to get the speed up again then I sheet in the sail until the luff stops collapsing. Once the sail has settled I then adjust my direction, retrim the sail and adjust the skeg. You can see all of this in the above video.

Welcome to the World of kayak sailing!


  1. Brilliant Douglas. I haven't sailed for many years but I'd really like to try out one of these. I'll have to get myself to Ayrshire one of those week ends.

  2. Hello Douglas, this is really helpful.I have recently got a Flat Earth sail but found sailing to be a bit more complicated than I thought with difficulty controlling direction unless the wind was from behind. I have been sea kayaking for over 25 years but have never sailed before. The top two pictures are very much me! I had bought a dinghy sailing book but soon realised they have centreboards and rudders and it was less help than I thought. I shall practice your tips, I don't usually use much skeg and hadn't really thought about using it for sailing.


  3. good morning, one of the best tutorials iv read , I hope it helps to get the best out of others new to kayak sailing ,douglas your articals fare outsine a lot of the content on the offical flat eart kayak sail site.
    Mick MacRobb
    flat earth sails

  4. Douglas, it was me who watched you and David sailing in to Largs Marina from the Cumbraes back in the autumn. You were the talk of the sailing club! As a long time sailor I was very impressed that you got over in one tack. You certainly got me hooked and I hope to be on the water with Flat Earth in the spring. I would just like to say that your article is also helpful to sailors who are relatively new to seakayking like me.

    Thank you

  5. Douglas, I didn't know that kayak sailing was so technical. I guess if one wants to be efficient and get maximum speed out of a sail your suggestions are great.
    One thing I noticed is that I can control a bit the direction of the kayak in a beam wind by simply shifting my weight forward or backwards.
    As I apply more weight on the stern (lean my body back onto the coaming of the cockpit) my kayak would turn away from the wind (leecock). The kayak being empty so my weight shift is more pronounced.

  6. Thank you Arno, Geoff and Anne at Kari-Tek run really good demos, definitely worth a run up to Ayrshire.

    Hello Anon, the skeg is really useful for sailing, even if you don't normally use it much just paddling.

    Thank you Mick, and thanks again for producing such fantastic sails!

    Hi John, if you havn't got a sail yet, you should get along to Kari-Tek with Arno!

    Hello Gnarly, if you just want a downwind blast in plenty wind, you don't need to get too technical but if you want to get going in light wind then a bit of sailing knowledge can mean you extend the useable windrange at the bottom end. It also makes a huge difference to sailing upwind.

    With regard to weight, I put on nearly two stone after my knee injury and when I first started using the sails, I found that I could use my weight to alter trim in my Nordkapp LV, a little. However, I have since lost a stone and fore and aft leaning has less effect. Even when I was heavier, fore and aft weight shift made no difference in my Quest LV. I guess a lot depends on paddler weight and kayak type. Even in the Nordkapp LV when I was heavier, a tiny adjustment of skeg made much more difference than fore and aft weight shift. I do of course lean to the side to help keep the kayak upright.

    From your videos, you look to be doing pretty much everything right!


  7. Douglas,
    Can't resist getting a Flat Earth sail for my Alaw Bach - have you fitted one to yours/another? It looks as though the mast step will sit nicely in front of the bow elastics and I can use the deck fittings either side for the stays. My only concerns are the stowability of the mast given the raised deck of the Alaw Bach, and whether I can reach the boom/mast to stow the sail. I'm going to jerry-rig some garden canes as an experiment - could you possibly tell me how long the mast and boom are?
    Apologies for the odd request!
    Many thanks

  8. Hello Paul,

    just in front of the deck elastics, 89cm from the bow, is where I have mounted the mast foot, by coincidence the same distance from the bow as the Quest LV setup. The mast is 1.68m and the boom end when folded is 1.30 from the mast base, so it lies nicely to the side of the front of the cockpit.

    Have fun!


  9. Hi Doug - just to add to the comments - finally fitted the sail and had a chance to use it going around the IOW a couple of weekends ago. Blew a F5+ and the sail was never overpowered - even took it into some big water on a broad reach and felt really stable. Like you I was a sailor first and this took me back to those days - best of both worlds - a great design and I was amazed how easy it was in use! Mike

  10. Great directions on using the Flat Earth Kayak sail! I'll have to try the elastic on the fore stay sometime.


  11. Hello Greenlandpaddler, I too have been very impressed. We paddled 93km round Arran a couple of weekends ago and in a force 4/5 we paddled/sailed for 44km nonstop! We were on every course from about b60 degrees off the wind to dead down wind. Quite amazing amount of fun from such a small sail!


    Thanks Frank, I think the elastic on the forestay is what helps survive gusts when closehauled.


  12. I paddle a Prijon 17 foot plastic boat with a rudder. Will the Flat Earth Sail perform as well with a rudder control as with a skeg?

  13. Hello Robert, your ruddered Prion will be excellent downwind. We have Flat Earth Sails on Quests with skegs and a Quest with a rudder. Downwind they are all the same but as soon as there is a decent wind the Quest with the rudder has problems going upwind. If you put the rudder down it behaves like a large skeg and the Quest leecocks. If you lift the rudder it weathercocks and it is necessary to keep the bow off the wind using sweep strokes, not impossible but it is much easier in the Quests with skegs.


  14. Would one of these Flat Earth sails attach to a skin on frame or folding kayak (a Klepper single T9 in my case), or do they require a hard shell for the attachment points?

    (I guess a longer sea kayak might also be helpful over my stubby Klepper in terms of laying the mast flat without getting in the way of paddling?)

    They look very similar to the Kuvia Kayaksailor, which is slightly pricier but has a rather clever looking 'pop-up' arrangement.

    Anyway, thanks for your thoughts.

  15. Hello Ian yest the Flat Earth rig can be fitted to SOF kayaks, indeed Mic McRobb the designer usually sails his on a SOF!

    I had a look at the Kayaksailor rig before going for Flat Earth. The Kayak sailor rig is much heavier and much more complex than the Flat Earth.


  16. I have my new flat earth sail set up on my Prijon Kodiak. When I try to launch it, 80 percent of the time the mast sits straight, then topples into the water. I start facing downwind, then push the mast up smartly while pulling in the uphaul. The sail usually ends up in the water regardless of which side I try to launch on. Do you have some advice for me? Robert

  17. Hello Robert, did you buy the sail from Kari-Tek and have you rigged it with the shrouds coming back to jam cleats on the foredeck?

    If so I recommend that you rerig like I have with the shrouds fitted at right angles to the mast foot, of fixed length (and tight) and also fit a back stay.


  18. Hi Doug. I have a backstay, forestay (the uphaul), sidestays which are right angles to the mast and another set of sidestays that mount slightly toward the cockpit . They are tied as tight as I can get them. Robert

  19. Hi Robert, I have added a short video to the post above. It shows how I launch and recover the rig. I have never experienced the problem you describe. The rear two stays will not be adding anything to your mast's stability and are just complicating things so get rid of them.

    You didn't say if your rig was supplied by Kari-tek. My friend Mike got a rig from them last month and it was supplied with stretchy 4mm rope, deck eyelets and cleats back at the cockpit for the shrouds. We replaced these with 2mm Dynaema cord and snap shackles. It now rigs much better.


  20. I'd love to try this, maybe one day when I have some free time to get away!