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The Classic Sail Design – it worked beautifully!

This is how we build a kayak sailing kit. After testing the sail kit, both small and over-sized main sail, over half a dozen times, I’ve discovered more room for improvements from the findings.

The Balance

sailing kit balance

I now understand that there are 3 major elements that MUST be present on a sail-vessel (boat or kayak) to establish a forward force :

  1. Main Sail
  2. Leeboard (one on each side = 2 pcs) or a Daggerboard (one in the middle) or a Keel in various setups
  3. Rudder

With these 3 elements, you’ll achieve something called “Sailboat Balance” as pictured in this image.

To further understand this theory, click HERE for a crash-course into sailing.

Want More Sea-Horsepower??

If you’re looking for more speed or expect to sail out on a choppy water days with waves greater than 0.2m, I’d say you’ll need a bigger sail.

I found out that with the black sail I’ve had with the recent kit, I could not ‘tack’ upwind due to lack of power/force from my tiny sail.

Kayak Sailing
BIG Main Sail = Tipped over a few times, hard to control even in 5-6 knot winds

Its a decision you’ll have to make between Power and Control.
A BIG main-sail = Bigger sailing power, harder to control and risk of tipping over (capsizing) increases.
A SMALL main-sail = Lower sailing power, greater control and risk of tipping over would be lowered.

I reckon a main-sail neither too BIG nor too SMALL should be added to the kit to get the right “balance”. I might just cut this big sail into a medium size to fit the kayak for the next upgrade! **Update : I did cut it in half, and it worked!**

With that said, you too could look for a used sail, tent or tarp to cut down to size for your main-sail. Why not?

The New Build!

itiwit sailing kayak

Since we are working on building a sailing kit for an Inflatable Kayak, all of my designs have revolved around a bolt-on non-invasive style fitting.

If you also have an Itiwit Kayak from Decathlon, you’ll find it easier to build this kit based on my design, saving you some beer-time figuring out the functionality of every component.

My ultimate goal here is low cost, simple to assemble and lightweight. Let’s dive into the details.


The Leeboards are meant to provide a lateral force (sideways force) to balance the kayak. In other words, it keeps the kayak from sliding or ‘strafe’ sideways when sailing upwind or close to facing the oncoming wind direction.

leeboards to build a sailing kayak kit

So, you’ll need to make 2 identical leeboards with materials of your choice. I chose plywood because its easy to work on and easy to find. I found mine from a recycle center. If you prefer, you could also get some wide wood planks and plane them down.

My 9mm plywood worked fine for the many sea-trials recently and I hardly notice any flex in the leeboard for an Itiwit-2 kayak size sailing under 6-7 knots of wind force.

Leeboard Mounts

The pair of crutches that I’ve cut down worked perfectly! I could adjust/shorten the bar to get the leeboards to “hug” the inflatable kayak’s body, thus not swinging backwards and reduce chances of ‘snapping’ when sailing.

The screw used to mount the leeboards are called eye-bolts. They are pretty inexpensive. If you have that extra cash, invest in stainless steel ones and also get some stainless wing-nuts to compliment the set. I didn’t bother and went for the zinc plated ones and regular nut to fasten and loosen with a 10mm spanner. Spanner got really rusty afterwards, but that won’t stop me from hitting the waters!

Eye Bolt
Eye Bolt (Stainless Steel)

Stainless Steel Washers

The Leeboards and Rudder Board would be under good amount of stress when you’re sailing upwind and it’ll be rubbing on to the ‘crutches’ tube and the fastening nut. This rubbing/abrasion would cause a metal washer to rust over time.

I personally want this part to last a good amount of time before I rebuild the leeboards/rudder again. So, I went on eBay and bought a set of M6 40mm A2 Stainless Steel Penny Washers for £2.10/10pcs. I went on to glue them onto the leeboard mounting holes using 2-Part Epoxy.

DIY Kayak Rudder

Also don’t bother drilling holes for the Leeboard tie downs if you’re building this sail kit for an inflatable. It’ll just look messy having too many ropes around when you sail. You could just retract the ‘crutches’ leeboard mounting tubes to ‘hug’ the kayak and it’ll stay there, trust me.


No, not that foil for cooking your weekend roast dinner. A foil is a profile or shape of the Leeboard or Rudder board when you plane/skim it to cut through water.

Foils for sailing kayak kit
Various types of Foils

Don’t bog your head on this one, just go with the easiest and smoothest foil you can form with your bare hands and a good planer, grinder or a sander. Just try your best to make both leeboards identically formed.

When you’re ready for the ‘need for speed’, go ahead invest more time in building an improved foil rudder and leeboard.


I got my style or design of the leeboards from existing small sail-crafts pictures. Once again, there’s no right or wrong answer to what shape your leeboards you choose.

There was one website that I read about performance leeboards did mention that it all depends on your sailing speed (and size of your boat). Slower sailing boats have wider leeboards and faster sailing boats can/should have narrower leeboards.

Daggerboard by Hobie

I believe that it has something to do with water-drag effect on the boards. I’m not yet in the search of performance sailing, as long as it sails upwind, fast or slow, I’m a happy bunny!

If you’re building your boards from plywood which is cheap and easy to source, you can afford to make different styles and foils to try out which suits you best. Go ahead experiment!


I would say, this is by far the most challenging part of my build. It looks easier than you think especially when you’re building one to fit a (soft-shelled) inflatable kayak.

Rudder Mount

Your first step is making a mount or a hard ‘cap’ to fit snugly onto the kayak’s tail. There are many ways to make one of these important component.

Some kayak sailing builders used anything from nylon chopping boards, plywood, and PVC pipes to create that snug fit to counter the ‘torsion’ or ‘twisting’ effect when you turn the rudder left/right while sailing.

In the beginning of this current build, I didn’t have much patience with figuring out the best rudder mount and just went with buying a rainwater-gutter end-piece. I used a heat-gun and bend the PVC piece into shape just enough to hug the tail of the kayak.

B&Q Gutter
UPDATE : This was an older design. Click HERE for a new design.

I’ve also drilled 4 holes to tie 4 cords to secure this mount to the kayak’s existing bungee-loops and rear carrying handle. It worked fine, but I’m now building a new rudder mount from a hard plastic bin cut-out to better hold the kayak’s tail giving the extra turning force. Its under construction, so stay tuned! Subscribe to our YouTube channel to get alerts when we’ve uploaded this new update.

Inflatable Kayak Rudder Mount
The Rudder Mount
UPDATE : This was an older design. Click HERE for a new design.

Rudder/Tiller Frame

I’ve always wanted the sail kit to be as light as possible and still strong. So I headed down to the recycle center nearby to hunt for some parts and there was a golf-bag trolley with a half broken wheel.

At first I thought of using this golf trolley to carry the kayak down to the water. But it ended up becoming the rudder/tiller’s frame which was great! There were plenty of bolts, nuts and washers on this old trolley that I reused most of them. And they are nylon-locked nuts that won’t undo themselves when in motion or vibration, brilliant!

DIY Inflatable Kayak Rudder

Ditto here, this was my design, you could come up with your own style that suits you best. Main function here is the lock-pin that acts as a pivot point to steer the kayak.

Inflatable Kayak Sailing Rudder
A bigger picture of the rudder assembly

Tiller Extension Stick

When I first saw a small sailboat, the first thing that caught my attention is this interesting looking stick. I don’t know how it worked at first, but it did look like something cool to have on a boat.

The Tiller Stick 😉

I haven’t got the time to get to this build yet, but I do have the materials. The tiller extension stick would be made of a golf-stick handle, which is made out of carbon, light and strong.

After a few sailing trips out with the inflatable kayak, I noticed that at some point, the tiller extension stick can be useful especially when you need to sit further forward in the kayak to maintain balance, at the same time control your tiller/steering. Without this extension, the steering will be out of your reach, which is …inconvenient.

Rudder Board

After the first sail out (Episode 1), I’ve learn’t a lot about how Rudder Board design effects the whole sailing experience. It probably is the most important ‘fins’ you’ll need on your sailing kayak.

First, it acts as a steering wheel to control direction of the kayak – turn left/right.
Second, it also act as a counter-force against the twisting motion generated by the main sail. Without this force, there’s no ‘sailing-forward’ action, only kayak spinning around in the water action lol.

Kayak Rudder
Yes, this was a major miscalculation of dimensions lol

This first version of my rudder board was a miscalculation. It was about 15% efficiency in turning the kayak, haha. I was just being optimistic at making the sailing kit lightweight and compact, also how easy the kayak could turn. I was wrong.

After this ‘incident’ I went back to my drawing board and recalculate another logical size of a rudder-board and came up with this drawing that you’ve seen on Episode 2. I’ve copied the outline of the rudder from a branded inflatable-sailboat website (that shouldn’t be named on here) but altered the shape/dimensions slightly to fit my rudder frame.

If you’re in doubt with the dimensions of your rudder board design, its always okay to make it bigger, as in wider and longer for your first piece. Then scale it down gradually when you’ve gained some sailing experience with your kayak.

That’s the same method our generation invented mobile phones back in the day, big and bulky, but it works. Today, mobile phones are almost paper thin and worked better than ever before.

Main Sail

What’s a sailboat without a sail? A Kayak, haha! We can say that because we have paddles just in case of main sail failure. Sorry big sail boats.

This is the fun part, designing your own main sail. There are dozens if not hundreds of main-sail styles and designs that you can freely source online for inspiration or even copy their exact dimensions.


In order to get your kayak to sail, you could literally use anything from canvas, ripstop fabric, mylar (proper sail material), tarpaulin, bed linen to shower curtains to build your main sail.

Now before you jump on Amazon, eBay, AliExpress, Lazada etc., you must consider a few things.

1. How much budget do you have for your first main sail?
If you don’t have much to spare, and just trying out this new hobby, go with the cheapest. Not in any particular order, tarpaulin, shower curtains and rip-stop fabric could sail your boat, literally. *ba-dum-tsss*

2. How long do you want it to last?
If you want this main sail to last for a very long time, go for Mylar, pro sailing stuff, and also the most expensive (in my point of view). To me, if it lasts 10 trips down to the beach at say, $20-30, that’s $2-3/trip of fun-time sailing. Not too bad.

If that is your cup of tea, go for rip-stop fabric. Same stuff I’ve used on Episode 3, the black sail.

3. How much do you wish to spend for looks/aesthetics?
As some sail materials easily looks ‘crumpled’ when you fold or stuff them away, you also might want to consider which material would suit your wallet.

Ripstop does crumple, but to very obvious. Mylar hardly crumples unless if you deliberately fold it like paper. Tarpaulin can get crumpled, but who cares if its cheap and sails. I’d love to make a transparent sail out of a transparent shower curtain someday, but I’m not sure how long they would last.

If you like vibrant colours, go for rip-stop fabric. There are a big variety of colours to choose from.

4. What tools do you have to build your main-sail?
To build a main-sail, you’ll need a sewing machine, or you can do all the cutting and get someone else to stitch it for you.

If you don’t have anyone to stitch one for you, its not end of the world yet. You could opt for tarpaulin and use strong waterproof double sided tape or glue to put all the pieces together. Theoretically, it should work, but I cannot guarantee how long it’ll last as I’ve never tested this method myself.


There are so many designs of main-sails you could possibly try out. Based on my experience from Episode 1, I understand that a kayak sail kit must come with a mast, boom and main-sheet rope.

Without a ‘boom’, the sail would just be good for down-wind sailing and upwind sailing would be a struggle. You could see the sail ‘curving’ in the video as it catches the wind but that won’t work when the wind is blowing from the left/right side of the kayak.

Unless if you have an original Hobie sail with dacron material that channels the wind on the sail’s surface to create the forward force effect.

how to build a sailing kayak kit
This is a boom-less system main sail for Hobie kayaks
build a sailing kayak kit
Found this on some random website, it has a ‘batten’ to the middle section of the sail.

After sailing on Episode 1, I noticed that a kayak sail needed a boom. So I added one and also added a ‘batten’ which was a piece of plastic to hold the shape of the sail even when the wind is not blowing.

Last version of sail with batten

The Batten was a great addition, but I noticed another problem, the sail started ‘twisting’ between the mast and batten from the wind’s force. I didn’t care if it added extra ‘power’ to sail, but it just looked …ugly.

So, now I’m on a new setup of mast, boom and a triangle shaped sail without batten. Stay tuned for the next post on this new design. The last time I tested it in 12 knot winds, it went strong!

DIY Classic Sail Design
The current sail design, no batten, classic triangle


If you’re planning to make a sail from scratch, I’d suggest you to watch this YouTube video set as it’ll explain to you the process of designing and measuring your sail -professionally.

I’ve never got a chance to build it professionally yet as I’ve only discovered this video recently after building the black and the colourful sail. You can give it a go.

Click here for the YouTube video link. Its a long video, so grab a drink, pen an paper to take notes. Skip to HERE if you already understand the concept of how a sail works.

Update to the Inflatable Kayak Sailing Kit

We have recently updated the Inflatable Kayak Sailing Kit design and setup to be more efficient. Learn more by clicking HERE or click on the video below to see more.