Tag Archives: IK rudder

Seawave Rudder MkII tested

Gumotex Seawave main page
Rudder rationale discussed
Gumotex’s 2016 factory version
Making the prototype rudder
Testing the prototype
Update 2019:
I’ve not used my MYO rudder since I made it in 2016. Partly because I’ve only done day trips predicated on nice weather, but also it’s all just more faff and clutter, not least the lines and footboard. As explained earlier, for gumsee07multi-day trips where you must deal with the winds you’re given, it’s a good idea. But even then, you only notice your relative lack of speed alongside others. Alone, you’re as fast as you are.
Rudders are not about steering or tracking as they are on powered boats; in a kayak they’re about enabling a more efficient, balanced paddling effort on both arms by compensating for the boat’s deflection for side winds. In a way the simple stock skeg-shifter (right) will do as well with much less clutter and weight. Or, use this rudder, but locked in position as an ‘articulated skeg’ in place of the Gumotex skeg for shallows and beach parking. That is handy to avoid stressing the stock skeg, especially when the boat is loaded. 

mullamulamap

While waiting for rudder bits to turn up, we went out for an evening paddle round Eilean Mullagrach. It was pretty calm but at no point did I think, ‘Darn, I wish I had a rudder’. When it came to turning corners we just paddled hard or dragged a blade and round we came.
But the Seawave rudder project carries on like a supertanker with a jammed… rudder, if for no other reason than it’s fun to experiment and a rudder can also work as an articulated skeg when locked out – something I may look into when it’s all done.rudderdyl
Ironing out the flaws with the prototype added up to attaching it more securely at the back and making the pedal board out of something more responsive and durable. By coincidence, all these components can be sawn from a single piece of 450 x 300 x 12mm LDPE chopping board (left) which costs from £8 on ebay in a range of colours. This is 50% thicker than the smaller board I used on the prototype plate so doesn’t need doubling up and gluing to make it rigid.
rudm211rudm21At the back I  slimmed the rudder plate right down to a simple strip of 65mm x 450mm, glued a block on the end to better support the gudgeon swivel pivot sleeve and added the crucial second fixing under the portaging handle (left). I also added a triangularish screw plate rudm23underneath (left, with red cord) so it all sits snug in the stern. With the hardware and saddle strap that now adds up to 306g (the rudder unit weighs 450g with its running lines). Even though it’s slimmer than the proto plate, it weighs about the same because it’s now 12 mil. But looks a whole lot neater.
rdd5The pedal board is from the same slab but uses stainless hinges, not zip ties. I’m reminded, you’re constantly making small adjustments as you paddle so pedals need to be as taut and responsive as possible. Once I’d trimmed the board and pedals a bit (left), with hinges it came in at 660g.
rudnee1The board and maybe the pedals could have been made from 8mm if there was some to spare – but an 8mm board wants to be ~450mm wide to sit snugly in the boat’s side channels. Like the rudder, the pedal board will be subject to strong forces in heavy seas so also needs to be solidly jammed in. Meanwhile, I noticed the floor-laminate prototype  board (right) gained nearly 15% in weight after getting wet – a sign it won’t last long. Still, it made a good template.
garbpedalsI do wonder if something like the Grabner rudder pedal bar (left, similar to Gael’s old H2) would be much lighter, as solid and as effective as my board. It costs €70 plus €30 for a pair of Zoelzer pedals.
I can’t really see how I could replicate that alloy footrest bar – out of copper tube filled with resin perhaps (like this motorbike rack)? It’s held securely in place without fittings by being jammed in the channel cavity between the floor and the sides (like my board), but a check with Gael advised me against it. As it happened, I’d pretty much decided the same mid test run (below). A sliding ally bar plus sea water isn’t a great combination and might bend or break, or the pedals snap. I know the ally backrest bar on my Amigo wasn’t up to it and Gael’s backrest broke (though it was ancient). My plastic version may weigh double but should be solid. Interestingly, just as a bag of clam cleats turned up make a quicker way of fine-tuning the rudder pedal lines from the cockpit, I see left that Grabner use them – a good sign.

rudhorserudm221The weather here’s about to crack and then we’re moving south, so in a rush I took the revised rudder plate out for a test with the creaky waterlogged pedal board. Heading towards Horse Island tidal passage, I didn’t need a weatherman to know which way the wind blew: from the WNW at about 12mph. Initially the boat needed constant small corrections to maintain a course, and there was some stiction, hopefully down to the zip ties on the soggy pedal board. I tried a few pedalotight turns and marvelled at the control and how sharply the boat swung round like a pedalo. The rudder plate is now as rock solid as anything fitted to an IK can be. Again, I consciously tried not to correct with my arms, just my feet, which were twitching regularly.
rudm24At Horse Island I was way too early to run the passage, but as it was probably my last paddle here till next year, I decided to head for Badentarbet. Turning north, closer into the wind the micro corrections were no longer needed and the boat ran as if on a skeg, but without arm corrections. I’m pretty sure paddling 20–30° off the wind would have required arm steering, but I just hacked away towards Rubha Dunan on the mainland as the wind increased. When I tried a bit of downwinding protracted rudder juggling was needed to keep the back-end in line.
rudgaprudm23I passed through a channel on the headland and the NW wind got steadily stronger so crossing the bay to the beach seemed to take ages of effort. By now the small corrections I’d been making were no longer necessary, perhaps something had bedded in, the knots had tightened up or like riding a bike I’d just got the knack of minimal rudder movement to keep the boat on track. But upwind paddling is comparatively easy so I tried across the wind, now running over 15mph, and a bit more downwinding which gave me that unsettling Ningaloo feeling. This must be the weak point of a buoyant, windprone IK (especially when unloaded), and maybe all kayaks and canoes too. The chop was only a foot high, but were there a swell of a metre or more, the rudder would be briefly lifting and the stern sliding. I wonder if in a such conditions a combination of rudder and skeg (which is always submerged) might be a way of limiting weathercocking? Or perhaps just more practice is required. There’s also another solution that might arrive here in time to try out.
rudruddAs I neared the beach the wind was hard in my face but I realised I was actually on good form, unlike on the Tanera run with the prototype. So I hammered away with all I had until my strake hissed onto the sands. Paddling hard is all helped by my brilliant, bent-shaft Werner Camano paddle, no less than ten years old this summer. It still clips rudaliotogether with a satisfyingly ‘clunk’ and has very little play. If it ever got lost or abducted by aliens I’d buy another without hesitation.
I was glad I’d got stuck into a longer test run than planned, and am now confident my MYO Seawave rudder is in the ball park. Hopefully the new pedal board will complete the job. 

  • Total weight: 300g rudder plate + 450g rudder + 660g pedal board + ~100g rigging = 1.51kg (3.3lbs), or < 10% of the boat’s weight
  • Total cost MkII version: £20 rudder + £15 rigging + £8 LDPE board + £10  hinges + £2 fittings = £55

rdd4rdd2For about £200 posted I could have installed a 2016 Seawave rudder kit, but from all the images I could find at the time it was unclear exactly how it secured at the back – there must be their version of an unseen triangular underplate, but even then it’s still a stressed-out single point attachment. My additional under-handle fixture eliminates pivoting. And the plywood Gumotex footboard (right) gumrud3appears to sit loose and seemingly will also pivot on that single strap. Production versions may differ and let’s not forget that adding all this complexity also adds a risk of breakage or damage. The simplest solution is usually the best, but the 160-g skeg will always be clipped in the boat as a back-up and a Seawave is controllable (if much slower) with no tracking aids at all. It’s worth remembering: a rudder isn’t about day-to-day tracking, it’s about maintaining a course when the boat gets pushed about in stronger winds. In such conditions a skeg is essential and a rudder is an improvement, as explained here.
rudstashrudderweightsOn the beach, prior to lugging the boat over seaweed-clad boulders, it took only 30 seconds to unclip the rudder mechanism from the plate to pre-empt stumbling and damaging it. Since then I changed the rudder plate mounts with tool-free knobs and an eyelet (left). When rolling the boat up it was best to pivot the rudder plate around the drain hole 90° to pack better.

rudm25

2016 Seawave with rudder option

Seawave main page
My MYO rudder (MkII)

gumrud2The 2016 Gumotex Seawave has had the stern slightly adapted to take an optional rudder kit. They’ve also improved the velcro bands for the optional deck by using Nitrilon, but it’s the rudder that’s the interesting development.
Coincidentally, P1150820I was  halfway through adapting a cheap SoT rudder for my Seawave (right) and the factory version (going for £150 from bluewatersports on ebay.uk) gave me some good ideas. The Gumotex rudder kit could be easily fitted to first-model Seawaves, and possibly to other Gumboats with similar triangular stern decks, like the Sunny and 410C.
gumrud5gumrud61For the time it took to make mine I could have fitted a Gumotex kit ten times over but with only these pictures I was unsure exactly how it was secured. I suspect there’s an additional unseen plate underneath the stern decking to help jam the whole set up securely into the back triangle of the boat. Otherwise the plate would be prone to distortion under rudder forces, giving a mushy response. I got that on my prototype version.
gumrud4The Gumo’s rudder’s retraction method seems to be pull-up-and-in, (right) whereas my SoT example above is a more conventional swing-up-and-over which puts the rudder right out of the way over the back of the boat. IMO this is better for negotiating tight turns in narrow sea chasms where an unexpected swell could crunch your protruding rudder blade.
gumrud3At the pointy end the pedal board looks reassuringly basic (and easy to copy) and the only obvious difference between an old Seawave are the two line guides gumrud1on the stern deck (right) which I added to my boat to make a straighter, drag-free pull on the lines.

Seawave vs Gumotex 410C + skeg-rudder mod

Seawave main page
The new Solar 3

gumsee02I had a visit from former Olympic slalom trainer and canoeist Jim the other day. He bought a Solar 410C after browsing IK&P and declares it one of his favourite boats. I ran the previous version Sunny for years before I felt I’d squeezed all the potential from it and started changing IKs every year. The Sunny was a tough do-it-all boat and the 410 is the same, but 20cm longer. It was more space but also the greater rigidity of higher-pressure boats I was after.
qefWe were hoping to go out for splish-splosh but for the last few days a cold offshore F4-5 northerly has been spinning off a North Atlantic High and bearing down on the Summers so games are off. Right now the chilling drizzle is nearly horizontal as it blows past the window. Oh hold on, it’s gone sunny now. Is it autumn already?
gumsee03The 3-seat, 410cm Solar went for as little as £550 in the UK or up to £100 less from Boatpark in Czech when on special. Both do free delivery anywhere. The Seawave costs about half as much again.
The 410 is a foot shorter than my Seawave, an inch wider maybe, less slim and pointy at the ends and runs 0.2 bar/3 psi compared to my Seawave’s 0.25 (I run my Seawave sides at 0.33/4.8psi). The old style Nitrilon is thicker so the weight’s the same at 17kg, maybe less with one seat. The Seawave has a bit of a more pronounced keel rib along the middle too, but neither struggle to track without a skeg. It’s just that a skeg enables you to spend less time and effort correcting and so you can power on. Handy at sea, less essential in flowing rivers.
gumsee07gumsee05Jim showed me an interesting mod to make his skeg into a rudder to enable paddling into steady winds. By simply not fitting the back of the skeg into the sleeve, he’s able to pivot it off the front and modify the angle with a bit of string attached to the back of his seat (right). No probs with the skeg sliding out and if it does on a rock, chances are you’ll be close to shore and the boat won’t exactly become suddenly uncontrollable anyway.
gumsee08I usually deal with quartering – ’10 or 2 o’clock’ – headwinds by just pulling harder on one arm, leaning into the wind or repositioning the paddle in my hands longer on the leeward side. I rather lost faith in rudders on the Incept in Australia when it was maddeningly ineffective in controlling the boat in strong backwinds, although I fitted one on the Seawave in the end. But without all the foot control faffery this could be a simple, non-permanent mod to any Gumboat which runs the robust, slip-in black skeg. And unlike my Incept rudder, it won’t come out of the water and be ineffective on steep backwaves.
gumsee10He also showed me a way of simply rigging up his roof rack tie-downs into thin knee braces (left). Like me, Jim agrees they’re a great benefit to paddling efficiency in an otherwise unbraced IK. I have some Packrafting Store ones on the Seawave – a lot lighter than my old SoT braces.
And he also said he’s successfully tried an idea I though of in my Sunny days, but never tried: hull rigidity rods to make the long but low pressure boat flex less. Either two on the sides which requires gluing fixtures to work best, or as he’s found, simply putting a thick broom stick or whatever under the seat in the middle of the boat.


In other news, I’ve been persuaded to cough up 25 quid a year to dump the automated ads on IK&P. I never see them as I’m always logged in, but they sure are tacky.

noadnoad