GEAR: sea kayak sail_update

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Several years of using sails on my sea kayaks has lead to refining my initial set up.
I no longer sew my sails but I still create my rigging, using custom made carbon masts.
On some narrower kayaks my sail set up was not as bombproof as I would like it to be where in a strong breeze (above 20 knots) the mast would not keep vertical and the little polymer base would deform under the lateral pressure of the wind. In a beam wind I would like to have my mast in a vertical position, making the sail more efficient and increase a bit of speed.
Mick at Flat Earth Kayak Sails has developed a brilliant way to reduce the down pressure on the flexible joint and is now shipping his sail with a new system where the mast contacts directly the removable fitting.
I want to use carbon fibre masts but I have been unable to find an off-the-shelf mast that would replicate Mick's system.
Not wanting to bond aluminum to carbon to create the oversize sleeve for the mast, the only way I could achieve what I wanted was to modify my existing masts to create the sliding foot sleeve.

mast uphauled
Instead of having a larger diameter mast running the whole length, I just made a short sleeve out of glass fibre tape wound around a tube of slightly larger diameter than my carbon mast. Once cured I bonded a the sleeve section to the base of the existing mast and covered it with carbon cloth for strength, and looks :-)
The sleeve section slides over a stubby base with the flexible polymer allowing the mast touch the actual hard surface of the red plastic base.
No load is now exerted on the polymer so it will no longer deform when the mast is uphauled and cinched down hard.

mast lifted for demo purposes
Of course the mast can still be lowered as before and when the sail is folded onto the deck the mast slides back up just enough to allow the flexible polymer do its job.



To prevent the sliding mast and the stubby base come apart I have used a short piece of shock cord threaded internally holding the two together.



I have also improved my anchor point for the stays on the mast.
I no longer use a stainless steel ring riveted with a saddle to the carbon tube but I prefer the use of soft Dyneema core line bonded directly to the mast with a section of carbon fibre cloth.
The load is distributed better and there is no risk of cracking the thin carbon tube with the pressure of installing (pulling) a stainless steel rivet.

mast rotated to show the carbon cloth anchor for the Dyneema cord
I have been using the new recessed anchors with great success, locating them right on the seam of the hull/deck to achieve a wider stance and a better load angle.
The stainless steel shackles are now heat shrunk (see warning below) to the Dyneema stays so they don't rotate when the sail is lowered on deck.



The whole assembly, viewed from the bow.


WARNING:
update 04JAN13
Richard Sharp from SEQSK has this to say:
"I had the sail up in 20knots and got hit by a gust which tipped me in. It
was at that point that I noticed the sidestay had snapped. Finding it hard
to believe that this was possible given the breaking point of spectra, I
examined the break closely. It was then that I discovered that where it had
snapped the internal spectra cord was melted together. See the enclosed
photos."





It appears that the core has melted while the outer sheet remained OK.
Using a heat gun at close quarters causes the Dyneema/Spectra fibres to fuse and become very weak.
The melting point of Dyneema is much lower than the outer polyester (pictured here black) and no noticeable damage was visible from the outside.
He now prefers to use the heat shrink only over the loose end of the rope, not over the entire knot and apply very gentle heat for longer to allow the tube to shrink.

GEAR: Flat Earth Sail Code ZERO

Flat Earth Kayak Sails has provided me with a new sail for testing.
I have been very satisfied with the design and quality of Mick's sails in the past and I now use them exclusively on all of my kayaks.
I believe the design is superior to the ones I designed and they are easier to use.
While Mick can supply a complete sail set (sail, mast, deck fittings and sheet) I use my own rig that is slightly different to his standard approach.
I was keen to try his high mounted sails with the stays below the boom for this new sail but I realized I would have to modify some deck anchors so I decide to simply slip the new sail on my existing mast and stays; there has been no modifications to the rigging.
The new sail uses Code Zero sail cloth: a very thin but very dimensionally stable material that has reinforcement filaments laminated into the surface.
The material does not stretch and does not wet out as much as conventional sail cloth keeping the sail light and maintaining its shape when dunked in the water.
I still remember the difference a wet or dry sail made when I used to windsurf: after a water start the sail seemed sluggish and slow to gradually become more taught as the sail would dry out. Once fully dry the fabric would shrink and the sail was “fast” again. I am not sure if the surface area of a kayak sail is affected as much as a windsurfing one but having a dry fabric seems an advantage to me.

FEKS Code ZERO 1 meter, fully deployed
The sail is shaped differently than my other two FEKS: the shape is fuller and closer to the mast that flattens out towards the rear. There are more panels sewn into this sail to create the efficient shape. Mick’s sails seem to be less susceptible to wind change directions and they don't need constant trimming to get the maximum power from them, if compared to my own designed sails. In other words they are more forgiving. What makes them even more user friendly is the shock absorption built into the main sheet. When the sail is hit by a gust of wind the bungee cord stretches and spills some of the wind to possibly prevent a capsize of the kayak.
My new sail is rather large: 1.0 m². For a sea kayak sail that large surface can become a handful in higher winds (let’s say above 20knots).
When on a kayak sailing outing on a few occasions I had to lower my sail and stow it away when the wind picked up beyond what I could comfortably handle in my kayak; the sail was just too big for the stiff breeze.
Mick has engineered a simple solution to reduce the sail area (reef) and make it still usable in higher winds.

reefing points with simple Dyneema loops
I have used a very thin Dyneema line to create simple loops that can tie around the mast and hold back a section of the sail . The reduced area (0.5 m²) is much more manageable when the wind really blows. Unfortunately I have not come up with a solution on how to reef the sail by myself when seated in the cockpit; I need somebody’s help to do so.

sail reefed to reduce the surface area
My first outing with the Code Zero consisted of a short trip to a small island and back across a tidal flow channel. Initially the breeze was very gentle (just a few knots) to suddenly change to a solid 10-15 knots with several higher gusts.
The sail performed very well in those breezes but I had no opportunity to try it in something more challenging to the point to have to reef it and observe its performance when the surface of the sail is reduced.

in this configuration the sail can be used in higher winds without overpowering


The Code ZERO sails will be available in a limited edition in early 2012.

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FAIL: sail set up

I have noticed an increase in popularity of the single-mast sails for sea kayaking. I find the forward (of the hatch) mounted sail to be the easiest and most efficient sail to use while paddling.
I never liked the twin mast one and even less the step mast ones where the sail would interfere with my paddling stroke.
I believe that a collapsible mast is a safe sail too, taking only a split second to depower when the wind suddenly becomes just too strong to sail.
I currently use Flat Earth Sails and while they are more efficient than similar style sails (lateen) they require thoughtful mounting.
I have seen and read about sails that have failed when the breeze picked up above 15 knots; surprisingly those failures could have been avoided if the sailor would have set them up correctly.

A single mast sail should be kept as vertical as possible when sailing since tilting the kayak away from the breeze usually spills the wind and slows the boat down.
While often unavoidable, a paddler should counteract the heeling of the kayak to maintain proper balance and forward momentum.
When I set up a sail on my kayaks I take a fair amount of time to create the perfect-length stays. I  secure high quality line (always Dyneema) to a very solid anchor on deck.
My anchors are spaced widely apart on the edge of the kayak's deck. Using existing deck fitting for anchors only works if they are in the right spot.Early experimentation demonstrated that stays too close to the base will not keep the mast upright.
Proper length stays are a critical component to successful sailing.
As unsolicited advice can be met with contempt, I often refrain from commenting (on the spot) when I see a set up destined to fail.
I have witnessed stays attached to the kayak's perimeter lines because the owner didn't want/care to create proper anchors for the stays.
When perimeter lines do stretch under the strain of the wind the mast would then often collapse.


not so good set up
Needless to say the paddler would then blame the sail manufacturer and tout that his sails are rubbish.

So how do you set up the sail to keep up in strong winds?
I mentioned Dyneema line, in my opinion the crucial part. Nylon stretches when wet and elongates under load.
Secondly I make sure that the stays are just a bit on the short side. When the wind loads the sail the polymer mast joiner (base) deforms a bit and compresses. A stay that is a bit too long would then angle the mast precariously.

sail about to collapse
Lastly I make sure that the deck of my kayaks don't flex under the base of the mast.
Most kayaks' decks are not designed to take a concentrated load in one spot. Peaked decks are better but often still not strong enough.
Since I don't like creating metal plates externally under the mast's base, I prefer to reinforce the deck of the kayak internally. A few layers of quality fibreglass cloth (even carbon, if I have any scraps laying around) make a much neater set up than agricultural looking metal plates, in my opinion, and lighter.

sail set up with mast in upright position
I use quality cleats that keep the uphaul line in position. I hate nylon cleats that let the rope slip.
A tensioned uphaul will keep the mast upright.
And finally the fasteners that keep the stays attached to the deck anchors.
I don't use snap links and even less clasps.
Nothing is more solid, secure and unobtrusive than a proper small "D" shackle.
It might take a second longer to secure it but I am positively sure it won't let go.

So, if your sail set up has failed you consider checking the above pointers.
If any other cause is not keeping your sail upright I might be able to advise you on a solution.

JUL 2012: updates on sail set up here
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SHOP: retractable grab handle

The latest addition to my fleet of kayaks needed a toggle handle to be repositioned since I deemed it to be attached in a dangerous location.
The kayak’s deck is designed to accommodate an optional rudder and the designer could not attach the grab handle at the stern of the kayak since it would interfere with the rudder.
I have previously detailed the reasons why I regard some grab handles and its position on some kayaks dangerous. After a few pinched fingers and a bruised knuckles I now like to have all of my handles attached at the ends of my boats.
I believe that the best handle on a kayak is the single cord (not a loop) one from SKUK (Nigel Dennis).

handle on SKUK Exporer
While some argue that it is not as easy to use in an emergency towing situation (no loop for a carabiner to be attached to) I prefer that type of set up to prevent injuring my fingers.
One thing that I don't like is the banging that the handles produces when the kayak is paddled in textured waters. Some other set ups (like Valley kayaks) have a bungee cord tensioning the handle back onto the deck which stops the annoying banging.
Then it dawned on me: why not combine the two? Why not tension the single line?

the handle was originally attached on top of the deck
While simple in concept the details of the execution and the quality of materials for this handle set up must be first rate.
I used a sheeted Dyneema core 4 mm line for the cord and quality bungee cord for the retracting/tension section.

Dyneema line through a sleeve in the hull
A knot joins the two and a bit of heat shrink covers the ends to make it look neater. The knot stops the cord from being pulled through the sleeve in the hull. The bungee is attached to the toggle's original anchor point on deck.

Dyneema/bungee junction
The handle has a short stand-off from the hull so it can be grabbed easily when in a hurry (like in the surf).

handle with stand-off
The idea of having a retractable handle came to me after I had drilled and sleeved the end of the hull of my kayak.
If I had to do it again I would position the sleeve on a slant to alleviate the (right) angle of the hole and have it more in line with the toggle cord. That would achieve less friction when the handle is pulled out and possibly reduce the wear on the line.

PS You have seen this set up here first

SHOP: DIY sea kayak foot brace

A paddling acquaintance of mine announced that he wanted to sell his beloved carbon/Kevlar sea kayak.
His reasoning was that the factory foot pedals collapsed on him once and the replacement ones did not look any better. He was not confident with the outfit of his otherwise great kayak.
While jokingly I promptly offered him a ridiculous sum to buy his kayak I added that if the foot pedals were his only problem it would be unwise to sell a kayak that he loved.
After making a few suggestions, with a simple solution on how to remove the existing plastic pedals and fabricate an aluminum bar as replacement, he no longer wished to part with his kayak.
On the next paddle he proudly showed me the modification. Admittedly he did a decent job.
His feet were resting on a bar that was spanning across the width of the hull offering more than one foot position.
His replacement foot bar prompted me to finally address my own foot pedal set- up in my prototype SeaBird Designs Northsea.
The kayak I have is a preproduction one where the outfit was not fully finalized and the foot pegs rails were not positioned correctly. A factory retrofit was done to ship the kayak in time but the job was below my standard.
As they say: "You don't buy a house because of its furniture"; I decided that the flexible factory foot pegs had to go.

Factory set up in pre-production Northsea. These foot pegs were for a rudder (that I removed and replaced with a skeg)
I wanted a secure wide bar to push my feet against.
I removed the rails and the foot pegs and fabricated a new rail from anodized aluminum "L" section.
I used the existing threaded studs to mount the rails.

replacement aluminum rails: "L" section anodized profile
The cross brace where my feet will rest against had to be rather wide and curved a bit.
I could have used the aluminum profile that I have used in my other kayaks but the adjustment in the SeaBird was different: the pegs and rail have been removed.
I set out to fabricate a cross bar made from foam and composite fiberglass and carbon.
I cut a wide section of foam core and heating it up with a heat gun I shaped it into a shallow channel.
I cut a slot in the end to create a tab for anchoring it on the aluminum "L" rail.

heat shaped foam core
The foam core was layered by double bias glass cloth and West System epoxy (105/206).

double bias covered by 4oz glass
Once cured I trimmed the excess cloth off from the edges.
Subsequent sessions did cover the front side with carbon cloth.
Carbon added a lot of strength and made the brace stiff.
Unfortunately carbon is not very abrasion resistant and an area that would see constant rubbing of shoes and sand had to be protected with a final layer of 2oz glass cloth.

2oz glass cloth covering carbon cloth
The foot brace once cured had the anchor tabs drilled and a last coat of epoxy was done for durability and looks.
Installing the cross brace meant careful alignment on the aluminum rails and a row of holes for adjustment (different leg lengths).
I used a 1/4" stainless steel bolt and a wing nut (rubber washer) for securing the foot brace.

Replacement foot brace installed (not shown with wing nuts but nylocks)

DIY: towrope system for sea kayak

The club I used to paddle with required that we carry a towrope.
Before purchasing a towrope I obviously looked at what others were using.
It appeared that just about all the systems that I could find were the type that mounted on the kayak's deck and the tow ropes that attach to the body seem more popular for shorter tows (whitewater).
Here in Queensland a tow most times will be required when a fellow paddler's gear malfunctions (rudder failure), the kayaker is seasick (in heavy swell) or injured and occasionally too tired to keep up/continue to destination.
I did not like the look of the tow rope attached to the body: while jerking around the waist of the tower, in my opinion, it tires the paddler too much (and is dangerous in heavy seas).
I looked at what towing system was common with expedition paddlers in Great Britain and I often saw a towrope stashed away in a bag, secured on the deck of the kayak, usually behind the cockpit.

The commercially available (to me) towropes at the time were usually of poor quality and too bulky and there was not much thought given to those systems.
I believed that I could improve on those designs and come up with a better system myself: my first towrope system mimicked the British set up.
I found however that the deployment and retrieval of the towrope behhind my back was cumbersome to me (I am not very "bendy").
I thought that the same towrope could be attached in front of the cockpit where I could easily reach it without having to contort myself.
towrope system securely attached to the front deck of SeaBird Northsea.
The front of the bag has a little loop of Velcro® to keep the bag in place when deploying the tow line.

Velcro® that loops around a bungee cord, securing the bag
The remaining problems were:
1) quick release in case of trouble and
2) the towrope staying clear of paddling radius.
I solved the first with a different approach than the usual cam cleat and I use a quick release shackle.

quick release shackle attached to front deck lines

2) to maintain clearance off the towrope when deployed, the line is routed through a loop next to the cockpit and prevents the towrope interfering with my paddling (and getting tangled).

Dyneema® loop next to my cockpit

The towline bag: custom sewn heavy duty nylon (Cordura®) with reflective stripe.
The cover flap is looped around a second bungee when on deck and Velcroed down to itself to keep it secure.I used a towline that would float, be strong but still compact: 2mm Ø Dyneema® is the perfect line. At a braking strength of more than 650 Kg I think there is more than sufficient strength (I have used lighter lines too and they seem to work as well).
I packs down way smaller than the typical polyester water-skiing tow-rope and it's easier for tying knots around the karabiners.

15 meters of 2mm Dyneema® core lineThe towing karabiner is a stainless steel one that has a little float attached to keep it from sinking if dropped in the water.

karabiner with float. Tow line is chained for easy deployment without entanglement.
I find nothing worse than passing the clip-on karabiner to somebody to see it drop and then have to pull-in all the line again to pick it up.
The Dyneema® line is bright orange for visibility.
The anchor point is not my deck’s bungee since I have seen some fail but my perimeter line deck fitting (in front of the cockpit).
The quick release shackle has a little toggle for emergency release, in case the towed kayak is putting myself in danger I can quickly just pull the toggle to release the line, even under load.

safety quick release in yellow
The towline has been tested in many towing situations and so far has worked great.
A couple of highly qualified sea kayak instructors have endorsed the system and asked me if I could manufacture the system for them.
For a commercially available product the closest one is the towrope from Valley (just a bit thicker line without the quick release shackle).
Needless to say that a rudderless boat works so much better for towing since there is no danger of the line catching on the rudder behind you.
I know that are countless arguments and counterarguments for towlines that are attached to the kayak versus the ones to the body.
This system of mine is working great for my paddling environment (quick rescues from turbulent waters around cliffs don’t apply) but I would not mind hearing from my readers if they see faults in this design.

edited DEC2011