Gumotex Seawave – MYO rudder

Seawave main page
Refining and testing prototype rudder
Making and testing MkII version

rudnee5After writing this a few weeks back I decided to try and fit a rudder onto my Seawave. On that breezy Mull trip Gael, in the rudneyruddered Incept K40 (right), seemed a little faster than me and the penny finally dropped as to why.
A rudder can compensate for winds pushing the boat off course while you power on as normal. Without one you’re pulling harm with just one arm in an effort to keep on course – that explained why I was a bit slower. Rudders have nothing to do with improving tracking which the Seawave does fine with the help of the skeg (though fitting a rudder means you won’t need a skeg). And unlike a ship, rudders have little use in ‘steering’ which a kayak does easily enough by dragging or drawing a paddle blade.
As mentioned elsewhere, skegliftanother benefit of using a rudder instead of a skeg means that you can park the boat on flat ground without it pressing on the skeg – particularly useful when the boat is loaded and heavy (left). I’ve often thought about fitting a hinged skeg at the back of the boat to enable this. It’s a way of avoiding the complexity of a rudder but with the benefits of solid tracking which is useful at sea.
It helped that I found SoT rudders from Hong Kong on ebay for 20 quid. For that price it was worth experimenting, just like it was for a knock-off disc sail. Here in the UK a proper sea kayak rudder costs around £200 for a full kit with pedals. I also learned that Gumotex had introduced a Seawave rudder kit on their 2016 model as I was halfway through this project. I’m glad I spotted it as it gave me some good ideas, while the cost and certain features of the Gumotex rudder reassured me that my MYO was a better way to do it.

Does an IK need a rudder?
ning-frontMost of the time on calm day trips a skeged Seawave manages fine without a rudder. But on a longer multi-day trip, or a scheduled one like Mull, you have to deal with the weather you’re given, or sit it out. As it is, unlike hardshells, IKs are innately more windprone as they’re lighter and sit higher on the water.
ningsailsI paddled with a ten-ton hardshell once in Australia with my old K40 (left). Where we could, we both had sails (right) and the hardshell flew along (a rudder makes kayak sailing much easier). But me, I had to give up on day two; I couldn’t control my kayak in the 20-30-knot backwinds, and that was with a rudder. On another earlier paddle in Ozzie in my Sunny I remember pulling hard on one arm for hours and days to counteract the crosswinds. I ended up with Fiddlerarms like a fiddler crab.
So with an IK the window of rudder usefulness – when winds are strong enough to require rudder correction, but before they’re too strong for all except short, white-knuckle crossings – is actually quite narrow. Say, between 10 and 20mph.
This’s why I’d sooner not spend £200 finding out if a rudder suits my sort of paddling. A rudder isn’t going to transform my Seawave and I may end up not using it much, as I’ve done with my disc sail (though having a rudder again may encourage me to give sailing another go). But a rudder will slightly extend my boat’s paddlability. When a brisk quarter wind blows from front or rear I’ll be able to set the rudder against it and power away with equal effort on both arms. Anatomical consequences? More Popeye, less Fiddler crab.
heliorudGumotex’s old Helios ran a crude rudder using the stern seam flap to pivot the rudder with very basic stirrups. The sea-slick Seawave isn’t made like that so needs some sort of fitting. Bodging etiquette requires that costs, effort if not time taken must be a practical minimum – and all additions must be reversible with minimum alternations to the craft. What I’ve made here is only a prototype which I’m calling Mk1. As you’ll read, i found many ways to improve it.
erudneychineeridThe Chinese SoT item (left and right) has a 16″ blade, minimal blade breadth, can be quickly removed on the pivot pin and k40rudneycan be both retracted completely from the water and dropped back in, using control lines. And better still, the retraction sweep comes right out and drops over the back of the deck, not sticking out vulnerably like the Incept rudder (right) or the Gumotex kit.

MYO
While the rudder inched its way here from Hong Kong I came up with a rough idea to mount it on a chopped up kitchen chopping board held in place by straps or similar off the rearmost deck line sleeves, then cinched down with an extra D-ring glued under the stern – the only mod permanently added to the actual boat.
On the end of the board some sealectrudgudgsort of gudgeon pivot swivel bracket device was needed – either a proper stainless steel bracket from SeaLect (right), or a block of whatever fixed to the board plus a ⅜” hole drilled through it to take the rudder pin. Rigidity, or minimal flex is important if the rudder is to feel responsive – another flaw I recall from the Incept. Mounting something rigidly on the end of an IK is tricky, but if my first ideas aren’t good enough, there’ll be other ways of doing it.
rud02The way I chopped my rud018mm board up and glued on the off-cuts for added stiffness produced about an inch of thickness at the back (right). And when the rudder turned up with a gudgeon pivot swivel sleeve, I decided it could be jammed into the back end of my board to provide a solid enough pivot.
This kitchen plastic is a dream to work with: it cuts easily, melts readily (no need for a drill) but is fairly light, stiff and rot proof. I mounted a clamp through the boat’s drain hole – crud04opied from the Gumotex kit – and used an off-cut with a melted-in M6 nut (right) to grip the top plate under the deck. With a strap threaded through the rearmost deckline sleeves, this triangulated the mounting to reduce but not totally eliminate sideways pivoting. When it turns up a ‘saddle strap’ through the under-stern D-ring will hold the board down to reduce movement some more.

Control lines
rud07rud08Having owned a ruddered IK helped with setting up the control lines. The pulley threading of the rudder lifting/dropping line pulley is fairly obvious – the goal is to create as little drag as possible and the many fixtures on the Seawave make this easy. I used bits of yellow fuel  line (above right) to make runners for the line which is more or less a closed loop from the rudder sliding through a karabiner hooked to a deckline sleeve left of the cockpit and knotted up to a plastic knob (above left). Haul back to lift the rudder; pull forward to drop. The trick is the get the length right before cutting off the excess cord. I might have done better using zero-stretch Dyneema cord here rather than cheaper paracord, but that’s easily changed if need be.
rudyardrud09One thing the rudder needed to improve the lifting line’s angle was a smooth shafted M5 bolt running through it as shown left. The holes are already there – maybe it’s supposed to be like that (no instructions with rudder, but you do get 4m of paracord). I originally used a zip tie (above right) until I realised it was squeezing the rudder plates together and cramping the swing of the blade. The bolt isn’t tightened and rolls as the red udder lifting cord passes under it.
rudlinesrud12The rudder pivot lines run smoothly through more fuel line slipped unobtrusively under the redundant splash deck tabs on the hull top (right and left).
mull11At the foot end attaching pedals to my big footrest tube (right) wasn’t going to work. I thought about using a smaller bit of tube but then decided a plain board with pedals pivoting on it at floor level works best – as Gumotex below right.
rudnee1I found a plank of laminate flooring in the barn, gumrud3sawed it into the right shapes and attached the pedals to the plate with zip-tie hinges so the thing would pack flat when not in use but makes the pedals stand up which is handy. This floor laminate was what I found lying around wanting to get the job done, but another slab of kitchen chopping board will be a better long-term solution. At least I have a template just as long as the pedal board doesn’t dissolve at the first splash of seawater.
rudnee2The pedal board is moveable front and back same as my foot tube was (for different length paddlers or two-up) but I need to find some way of fine tuning the 2mm Dyneema rudder line lengths to match. Something more than a spring cinch lock rudderlineloklike you get on a stuff sack that will actually lock the slippery Dyneema cord, but not need tension like the cam lock cleats I used on my V-Sail. I ordered the wheel locks on the right which should work.
ruddkitThe whole thing took a couple of days to work out using a jigsaw, a drill and a camping stove plus a skewer. If I had to do it all again and had all the bits and pieces at hand and a better idea of what I was doing (ie; this again but better) I reckon it would all take me 4–5 hours. Total weight added is 1.85kg, but I saved 450g by ditching my drainpipe footrest with a thinner version at a quarter of the weight.

The costs were:
• Rudder £19
• Chopping board £2
• 5m of 2mm Dyneema and paracord £11
• Five mini karabiners £2
• Two cord locks £1.50
Other bits and pieces I already had or found lying around might add up to another tenner.
Lessons learned: it pays to think it over: first ideas may give the impression of momentum coupled with intuitive brilliance, but are not always the best.

Next instalment: Oh rudder, how art thou?

rud15

rud14

rudnee4

 

This entry was posted in Gear, Gumotex IKs, Gumotex Seawave, Inflatable Kayaks and tagged , , , . Bookmark the permalink.

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