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Flat Earth Kayak sail rigging 2014



There's already plenty written about the Flat Earth Kayak Sail (FEKS), its a great piece of kit but if there is any weakness in the rigging it will show and probably at the most inconvenient time. I purchased the code zero 0.8 sail from Kari-tek It comes with a mast and rigging kit but as you'll see I've customised the setup.

This article is all about the rigging installation - not to be confused with rigging when preparing to sail.

Deck fittings
Mast and rigging
Stowing the sail on deck
In use
Strengthening the mast
Tip - cramming several cords through an RDF

Deck fittings

I wanted to utilise the existing recessed deck fittings (RDFs) as much as possible and the first consideration is where and how to mount the mast base. There are RDFs well positioned each side of the compass mounting so I decided that rather than using the supplied FE mast base I would make a custom base that fitted in the compass recess. I would never put a compass there anyway as its too far away to read, I use a Suunto bungee mounted compass that I can position nearer to the cockpit.

Here's one of the fittings to the side of the compass recess, I've made a loop of 3mm dyneema that goes underneath the open parts of the RDF and through the hole in the back part of the RDF with overhand stopper knots. Why dyneema here? because its important that there's as little give as possible in the side stays otherwise the mast will heel over more than the boat and the leeward sidestay will go slack. The loop is as near to the edge of the kayak as possible. This seems to be OK but really it would be better to install new surface mounted deck fittings further over the side to get as wide a spread as possible for the side stays which will be under a lot of strain. Similarly it would be better for the side stays to be attached further up the mast but that's limited by the design of the sail - more on this later.


Here's the central mounting for the back stay and the main sheet pulley. This is well positioned beneath where the sheet attaches to the sail to apply vertical downforce when sheeted in as there's no kicking strap. This time I've used a simpler cord of 4mm to make a loop to attach the backstay and a double loop of some thinner better quality cord through the pulley. The pulley is a cheap version with no bearings, its sufficient to provide 'feel' on the main sheet but as there won't be a great deal of movement I thought it wasn't worth a more expensive version with inbuilt roller bearings. See a tip at the bottom of the article for cramming several cords through an RDF.


Here's the central mounting for the back stay and the main sheet pulley. This is well positioned beneath where the sheet attaches to the sail to apply vertical downforce when sheeted in as there's no kicking strap. This time I've used a simpler cord of 4mm to make a loop to attach the backstay and a double loop of some thinner better quality cord through the pulley. The pulley is a cheap version with no bearings, its sufficient to provide 'feel' on the main sheet but as there won't be a great deal of movement I thought it wasn't worth a more expensive version with inbuilt roller bearings. See a tip at the bottom of the article for cramming several cords through an RDF.


and the mounting at the front of the kayak for the uphaul.


Note the clamcleats each side of the deck pod, one for the uphaul and one for the main sheet. The ball stopper and lead are for wrapping around the sail when stowing it on deck.


Here's the mast base mount in the compass recess. It's made from a basic kitchen chopping board about 8mm thick. There are two drain holes for water that can get into the recess, small stainless steel bolts (positioned to match a compass) and a 'keyhole' slot for the actual mast base. The screw head engages with the mast base to lock it into position.


At the heart of the mast base is a stainless steel universal joint I kept from my windsurfing era. The rest is again fashioned from kitchen chopping board and stainless steel screws.


Inserting...


In position


Rotate 90 degrees clockwise to lock. It's very robust and secure.

Mast and rigging

The business area around the mast; it comes with a riveted 'saddle' that provides an anchor point for the rigging. I've looped the side stays above it and around the mast to get them as high up as possible. The yellow dyneema loop is for attaching the forestay / uphaul. The white cord is the backstay. The short black length of bungee and hook is to secure the sail on the mast - see later.


Sidestay attached


The backstay is dual purpose. When the mast is erected the ball stopper runs up against the shackle locating the mast in the upright position. The 'tail end' of this cord provides an essential means of getting the sail down. When the going gets a bit too exciting you might find yourself screaming off downwind and with all the force being forward on the sail even if its sheeted out and flapping around the front of the mast, this is the only way you're going to get the sail down.


The frontstay / uphaul attached to the kayak.


The frontstay / uphaul attached to the mast.


Uphauling the mast


In the following two pictures you should be able to see that the sidestay mountings are just behind the mast by between 1 and 2 cm.


Mast attachments


Mast now in position


View from the cockpit.


Three quarter view.


Notice the bungee loop and hook to ensure the mast will not come off the sail.


Backstay and mainsheet attachment point with tail end of backstay leading back to the cockpit.


Backstay tidy and easy to pull sail down - note the end is tied so it can't be 'lost'.


Mainsheet cleated and spare cord tidy - note the end is tied so it can't be 'lost'.


Uphaul cleated and spare cord tidy - note the end is tied so it can't be 'lost'.

Stowing the sail on deck

All that's needed is to release the uphaul and usually the sail will collapse towards the sailor. Its then a matter of carefully and neatly folding the sail around the mast, boom and batten so it can be held down.


Going back to the view from the cockpit the arrowed lines point to the bungee loop for stowing the sail.


Under and over once...


..twice and secure the ball stopper in the loop. Note this is 'outward over inwards' so the ball stopper ends up inboard so it doesn't foul one's paddling stroke which may come close to the kayak.


There's an art to folding the sail neatly so you don't put creases in it and it's not a nuisance when stowed. I sometimes use an extra velcro strap around the upper part of the sail.

In use

The setup is working well, it's been used up to force 5 but not really beyond that yet. I reckon the side stays are the crucial part of the design. Consider a regular sailing yacht, there are literally tons of tension in the side stays and the mast is supported by a pillar that connects with the bottom of the boat. The problem is that on the FEKS design the sail is mounted well forward at a narrow cross section on the kayak. The side stays really need to be nothing less than as wide as the boat cross section at that point and also to be attached higher up the mast - the rigging is designed to suit the sail. An alternative mast / sail combination might not use side stays at all but instead be like a Laser dinghy with a rigid base which the mast slots into. Alternativey some kayak sailors mount the sidestays much further up the mast but to do that impacts the sail.

Strengthening the mast

Why ? Where the side stays are attached to the mast is the position of maximum stress, if its going to bend or break this is where it's most likely. A length of wooden dowel inserted in the mast in this area will provide extra strength in two ways; firstly by extra resistance to bending and secondly (more important), by creating a sandwich construction in that area. When a tube is bent it will initially crumple - the dowel will provide resistance to crumpling.

On the Kari-tek rig the saddle is riveted onto the mast. I've not used the sail much yet but already there are signs of corrosion between the stainless steel of the saddle and the alloy of the mast.


This shows where the dowel (~30cm) will end up inside the mast.


The rivets need to be removed as they protrude into the space inside the mast. Using a good quality drill and a little oil (as the rivets were stainless steel) I drilled out the rivet heads and then with a hammer and punch and good support for the mast, forced the remains of the rivets into the cavity inside the mast. The saddle is re-attached using stainless steel screws which will bite into the dowel. Before tightening the screws some vaseline is smeared on the area where the two metals touch, to delay corrosion.


The dowel was standard 17.5mm and needed sanding down for a firm fit, ie forced in with the mast base. When water reaches the dowel it will expand slightly and become a tight fit.

Tip - cramming several cords through an RDF

This can be frustrating because if you try and push a cord through a tight hole, the end will expand, and only make the process harder. When dealing with bungee cord this issue is even more pronounced. So the trick is to pull a cord through using a piece of wire.

Keep a thin length of steel wire. Using needle node pliers pierce it through the cord about 2 to 3 mm from the end. Pull it through and bend the wire evenly. Thread the wire through the hole in the RDF and use a combination of the pliers to pull the cord plus some wiggling of the cord that is yet to go through the hole.

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