Tag Archives: rudder for Gumotex Seawave

Seawave 2: Kayaking the Sussex Coast

Once we were let out in the Covid summer of 2020, we did a very nice coastal walk from Hastings to Rye along the Sussex coast. Hot, but not so windy, it would have been just right for paddling. Today conditions were similar for a westbound transit from Rye back towards Hastings.
High Water (and a spring tide too) was at a very reasonable noon in Rye, with a forecast of 8-14mph from the east and a bit of a kick at 3pm. I was hoping for the upper limit and a bit of splashy sport, so brought the WindPaddle I’d used on the packraft last month in Scotland in much stronger winds.

It’s only a 10-minute walk from Rye station to a boat ramp on the quay where the water was still inching up the concrete as I pumped up the Gumotex.

I was taking a gamble trying my untested new rudder set up. Because I expected it to play up, I fitted the stock skeg so I could lift a problematic rudder and carry on as normal without coming shore. To be without a rudder or skeg with a backwind at sea would not be ideal.
Being the ever recirculating goldfish, I forgot to try out my sail stick mount idea.

Rye hasn’t been on the coast since 1287 or so when, along with gradual land reclamation, the biggest of a series of 13th-century storms filled the adjacent marshy inlet with silt and shingle which finished off semi-abandoned Old Winchelsea and radically redrew the low-lying coastline where the Kent and Sussex borders meet. It was the same in Pevensey to the west.
The gif on the left from this interesting regional website shows how the coastline of southeast England was transformed in the late medieval era. Where the Rother river once flowed directly east to enter the sea at New Romney, the filled-in bay saw it diverted south below the old hill town of Rye, now stranded two miles from the sea.
The then important port of Winchelsea was rebuilt on its present site in 1288, but eventual silting saw both it and Rye’s maritime importance decline. What this area may lack in epic spaces common to the north and west of Britain, it gains in fascinating history. 1066 and all that.

I set off along the River Brede which wraps around Rye’s south side like a moat, and soon joins the Rother. It’s about 5km to the open sea.

I’m into the wind but the grass banks are under water and the wind turbines are spinning merrily; all good signs.

Rye Harbour. The tide is high and I’m moving on.

In 45 minutes I reach the old breakwater opposite Camber Sands where I recall bucket & spading as a child. The sea looks depressingly flat.

Seals at the river mouth (a few days later).

It’s nearly 10km to the distant cliffs, a two-hour haul. And with the breeze from behind, I’m soon streaming with sweat. I’m not sure my water will last.

Going with the Flow
A few years ago while planning Newhaven to Brighton, I learned an odd thing about Sussex and Kent tides. For the last two hours of the incoming (eastbound) flood, the tide keeps rising but reverses westbound along the English coast as it backs up at the Straight of Dover and spills back down the sides. That makes HW is around the same time in Folkestone, and 140 miles to the west, past the Isle of Wight, but HW at all the places in between lags behind.
Tidal steams are not that strong here – wind will have much more of a bearing on paddling – but this means you get only four hours eastbound flow with the flood tide and prevailing southwest winds. But if you time your run with a warm easterly off the continent and go westbound – as I did on this occasion – you get a much longer run with the tidal current; eight hours or more; maybe 45km all the way to Eastbourne. The question is: can you paddle that long.

A breeze picks up so I flick up the sail. I check my GPS and am doing 3-4kph, while I can paddle at around 5-6kph. Then the breeze drops away. I wasn’t really planning to paddle the full 30+ clicks to Cooden station, but I can always get off at Hastings, a few stops before.

At least the rudder seems to working as it should, though any quick response is dulled a little by the skeg. A rudder’s not really needed in these conditions, though it compensates for me being blown gradually onshore.
I’m trying a rudder lift-line only, not a rudder lowering line as well. But once in the boat I find I can’t turn enough to even see the lifted rudder to flick it down with the paddle, so I’ll probably fit a drop-line later.

I creep along the expanse of Winchelsea Beach. It’s hot work in a backwind. Eventually I reach the start of the cliffs where the coast turns more east-west, putting the wind directly behind me. But paddling at effectively wind speed, there is no cooling effect. More familiar with paddling at the other end of Britain, I’m not used to 27°C.

Then, as predicted, around 3pm the breeze picks up and I can get the sail up.

Paddling half a mile from the shore, initially it was hard to know if I’m moving and at what speed. So waking up the GPS screen was a handy way of telling if the sailing speed was worthwhile.
With the odd gust I reach nearly 7kph, but average less than 5kph, a bit slower than paddling, but I’m not dripping like a leaky tap or needing to drink. In fact I could nearly doze off.

The cliffs inch by. This is the sea end of the Wealden sandstone formation, less high and steep than the better known chalky Seven Sisters to the west, or Dover’s white cliffs to the northeast. Both chalk cliffs are part of the same formation or bed, but when the land was squeezed and uplifted to the dome or hump was eroded away to expose the older sandstone below. This is what they call the Weald, and near Tunbridge Wells, East Grinstead and Frant, the weathered sandstone ridge produces small outcrops where I started rock climbing as a teenager (right).

There’s barely a sensation of movement; it’s not as bracing as I was hoping

I pass the Stade, the east end of Hastings where the cliffs drop back down. A few souls are enjoying the last day of summer on the shingle beach.

I keep going to the pier and decide to have a leisurely take out there. It’s gone 4pm so another 10km to get the train 6.15 from Cooden would be a rush.

Landfall by Hastings pier.
Compared to the fabulous Summer Isles, for me these southeast coast paddles lack drama and interest, but are easy to reach if tomorrow’s weather looks good.
We walked Hastings to Rye again a day or two later; it took about the same time and was more enjoyable (though it was cooler).
The rudder foot pivot worked fine, though needed a bit of re-tensioning at the pier. Next time I can confidently leave the skeg off, though I can see a rudder would only be needed when sailing or paddling in windier conditions. That is all I have to say for now.

Seawave 2: Mk3 rudder (MYO)

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Gumotex Seawave main page

Rather like sails where I Made My Own, lost interest, then returned with a proper WindPaddle, after five years I’ve come back to the idea of fitting a rudder to Seawave 2. Mostly, this was inspired by a much simpler pivoting footrest tube idea from fellow Seawaver Jules, replacing cumbersome and bulky foot pedals. A rudder ought to make the Seawave more useable in a slightly greater range of conditions, including sailing which I tried again recently.

I could have bought the Gumotex rudder kit for just £219, but as always it’s more fun to piss about for hours and days on the pretext of saving money and conjuring up small improvements. IKs sit higher than hardshell kayaks, so I coughed up 25 quid for the longest rudder mechanism I could find on ebay: 510mm. It weighs 550g.
The stern-mounted rudder plate started as a slab of was a chopping board, then became an aluminium plate additionally located with velcro pads, as Jules and Gumotex use. I found secure clamping of the rudder mounting plate to be important to stop it turning on its axis. There is perhaps more torque on the mount than might be expected when a rudder blade tries to turn a 4.5-m boat. As you’ll see I ended up making a Mk 3.1 rudder mount in a mixture of soft and hard chopping board, as well as a Mk 3.2 in aluminium. There’s a 20g weight difference.
Another bright idea idea Jules had was running the rudder lines out of the way under the deck velcro flap and inside thin tubing. That largely eliminates any exposed lines. I also liked his idea of controlling the rudder by pivoting a drainpipe footrest tube from the centre, eliminating the need for cumbersome foot pedals. Overall the whole mechanism: rudder, mount and clamp (220g), cords and tube (50g), adds up to less than a kilo and under £50 (some bits I had already). Eliminating foot pedals was the main saving in weight and bulk.

Mk3 Rudder for Seawave 2

Items needed:

Ebay rudder assembly from £20
Piece of HDPE chopping board, 3mm x 400mm x 60mm, aluminium bar, or similar
Stick-on velcro
Hand clamping knob and nut
6 metres of PVC (or PTFE) pipe with 5mm internal diameter
11 metres of 2mm Dyneema cord
4-inch ø x 30cm plastic drainpipe footrest (if not used already)
2 metres of 25mm strap
A few mini snaplinks, fish snaps or similar

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Knob for rudder lift, cinch locks and clamcleats

Make 2 central slots, then attach the strap

Footrest
I already use a drainpipe as a fixed footrest. At 25cm wide, another 5cm would still fit between the Seawave’s sidetubes and may give a bit more finesse and leverage to rudder steering. If this proves the case with mine, it’s an easy swap.
Drill and/or hot-knife in two adjacent slots in the middle and feed the strap through. You must fix the footrest to the strap so there’s no slippage. A big knot inside will do. Thread the strap’s loose ends through the stock footrest attachments buckles on the boat’s floor. You can now easily re-position the footrest tube forward or back for tandem or other sized paddlers. This is handy whether you use a rudder or not.
While fine in the straight line along the hull top, putting a bend in the soft PVC tubing down the insides of the hull caused too much drag on the lines. So to avoid wear on the grey Hypalon, I just chopped the PVC tube back and stuck on some tape. (As you can see I need to add another strip for the tandem position). It’s probable the harder PTFE tubing Jules used causes less stiction, but having the rudder line exposed near the footrest-pivot make adjusting clamcleats and cinch locks easier.

Footrest-pedal in solo position. Tape avoids wear on hull

I stumbled on quite a fast and easy way to fine tune or readjust the footrest pedal tension: inline clam cleats (or cam cleats or rope locks) which I came across during my V-Sail experiments years ago. Feed the line through as shown below; centre both rudder and footrest, then cinch up and you should be good to go. Once you’ve established the right line length through the cleat for a certain fixed position, it can help to ‘memory mark‘ the cord (as I did in red). Though I bet once I get on the water and use the rudder a bit, they’ll go off alignment, so probably better to wait till then.

How to thread your clamcleat (rope lock)

You need enough rudder line slack to slide the whole pedal-footrest forward about a foot when paddling two-up. Loose ends can be tidied away with cinch locks. Eleven metres of Dyneema cord is enough to do this job on a Seawave, including a single rudder lifting line. (To push and drop the rudder too you’ll need another 3m.)

Rudder mount plate
The 10mm red chopping board I bought was actually quite bendy (LDPE, not HDPE?) compared to other bits I realised I had all along. The less play in the rudder system the more responsive it will be; an IK’s stern mounting is mushy enough.
This time round I copied Gumotex’s idea of using small velcro pads to stop the rudder twisting on it’s pivot-clamp axis. Initially lacking stick-on velcro, I glued plain velcro, using the PU glue from the Gumotex repair kit. For one-part glue, it seemed to fix the velcro pretty well but if not, some sticky-back came in the post.

I knew from last time I made a rudder the under-plate shape helps eliminate pivoting of the mount, but you can draw out the truncated triangle by simply tracing the converging top seams at the stern, then make the under-plate from whatever you got. I used a bit of plywood: jam it in snugly, mark the point under the stock drain hole, remove and drill. I glued and taped a nut to the back of the ply and added a bit of string to help pull the under-plate out.

I would have rather made the rudder top mount plate from ally but with little more than a hacksaw and a kitchen stool, lacked the tools to do a neat job. Then, while waiting for parts to arrive, I realised it was possible to buy ‘aluminium bar off cuts’ on ebay (right). Using the word ‘bar’ was the key. This place, or others like it, sell various sizes, including 3mm x 400 x 60mm for 7 quid.

I’m pretty sure most kayak rudders come with a 48-mm pivot pin of 9mm ø. Or was it originally 3/8″s, which is 9.5mm? The pin slips into a 10mm gudgeon swivel sleeve/tube. Some hardshells have this tube moulded in the stern; on an IK it must be built into the rudder mount plate.
Above left, you can see Jules (as well as Gumotex) integrate a gudgeon swivel tube into the end of the mount plate; a tricky thing to do accurately with a just a hand drill, though Jules’ thick plate makes it a bit easier. On my Mark 3.1 white HDPE mount, I glued layers of the old red LDPE into a block of plastic, then drilled a 10mm hole which works OK.

When it comes to an ally rudder mount, online you’ll find stainless steel kayak rudder pivot ‘C’ brackets for a fiver. They weigh 57g and are usually screwed to the vertical stern of a hardshell, replicating the gudgeon tube. Even though they’re only a fiver, it seems impossible to buy these from anywhere else but the Far East, and it would be more than a fiver’s work to fabricate that shape from hard stainless steel.
I bought a pair anyway; they arrived in a fortnight, but hole diameters (not stated in the advert) were 11mm, meaning 2mm of play with my rudder pin which feels too much. Oh China, your poor manufacturing tolerances let me down! So I glued on some 10mm washers to eliminate the slack. I’d have been better off making something after all.
It had occurred to me I could have bent my 400-mm piece of 3mm ally into a full ‘C’, either curved round a pole, or bent on an edge at two right angles, as up above left in cardboard. Tweak the alignment and precisely drill two 10mm holes and the rudder swivel mount and plate are all one piece. In fact, that 3mm alloy plate I bought was pretty stiff, so I settled on a simple L bend (and without a vice, even that wasn’t perfect), then glued and bolted on the Chinese ‘C’ bracket.

Not a perfect ‘L’ when bent in a metal gate frame

Rudder pulley
Rudder blades have a hole in the back so the pulley can lift and lower the rudder near a shore. For the moment I’ve decided to keep things simple and only use a single lift line, not a doubled-up line (another 3m of cord needed; 14m total) to lower the rudder as well. I intend to use the paddle to reach back and flip the rudder into the water. If that is a poor idea, I can easily add a two-way rudder line.
On packing up I realised this line needs to be in two sections if the rudder and plate are to be easily removable when rolling up the boat. The join can be at the back near the plate. As you can see I ran out of Dyneema and used an orange shoelace.

Separation needed to remove rudder but leave line

I fitted the lift line along the sides, using the deck support rib tabs and running through spare bits of tubing to avoid wear and aid smooth running. I fitted a tension-adjustable knob at the hand end of the lift line on the left, though anything will do. Pull forward six inches to lift the rudder. Flip the rudder back down with the paddle blade.

Does that flat, 4mm front edge of the rudder blade need chamfering to cut through the water, or am I other-thinking it? Who knows but watever you do, keep the skeg handy in case the rudder plays up.

Rudder blade could do with a sharp leading edge

Next job – see if it ruddy well works!

Seawave Rudder MkII tested

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Gumotex Seawave main page

Rudder rationale discussed
Gumotex’s 2016 factory version
Making the Mk1 prototype rudder
Testing the Mk1 prototype

Update 2019:
I’ve not used my MYO rudder since I made it in 2016 and sold it with the boat in 2020. 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 multi-day trips you must deal with the winds you’re given so a rudder is a good idea. But even then, you only notice your relative lack of speed (due to sidewind paddling correction) alongside others. Alone, you’re as fast as you are [grasshopper].
Rudders are not about steering as they are on powered boats; in a kayak they’re about enabling efficient, balanced paddling on both arms by compensating for the boat’s deflection by side winds.

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.

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 (above) 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.

At 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 (above left). I also added a triangularish screw plate underneath (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.

The 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.
The 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.

I 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 seawater 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 to make a quicker way of fine-tuning the rudder pedal lines from the cockpit, I see left that Grabner use them – a good sign.

The 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 tight 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.

At Horse Island I was way too early to pass through 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.

I 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 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.

As 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 together 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 ballpark. 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

For 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 any chance of pivoting.

And the plywood Gumotex footboard (right) appears 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.

On 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 (above). When rolling the boat up it was best to pivot the rudder plate around the drain hole 90° to pack better.

Gumotex Seawave – MYO rudder

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

Update 2019:
I’ve not used my MYO rudder since I made it in 2016 and sold it with the boat in 2020. 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 multi-day trips you must deal with the winds you’re given so a rudder is a good idea. But even then, you only notice your relative lack of speed (due to sidewind paddling correction) alongside others. Alone, you’re as fast as you are [grasshopper].
Rudders are not about steering as they are on powered boats; in a kayak they’re about enabling efficient, balanced paddling on both arms by compensating for the boat’s deflection by side winds.

rudnee5 — Mk1 version – needed improvements

After 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 ruddered Incept K40 (left), 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 hard with just one arm in an effort to keep on course – that explained why I was a bit slower. Rudders have little 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 even less to do with ‘steering’ which a kayak does easily enough by dragging or drawing a paddle blade. But you can of course steer with a rudder too.

As mentioned elsewhere, another benefit of a rudder instead of a skeg is 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 needed at sea.

It helped that I found SoT rudders on eBay from Hong Kong (and now, in the UK) from just 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 over £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.

ning-front — K40 with a (too short) rudder

Does an IK need a rudder?
Most of the time on calm day trips a skeged Seawave manages fine without a rudder. But on a longer multi-day trip 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.

I paddled with a ten-ton hardshell once in Australia with my old K40 (above). Where we could, we both had sails 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. (I realise now this was because the K40’s rudder was too short).
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 arms 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, aa 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 paddleability. 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.

k40rudney — Stick-out K40 rudder is vulnerable. Plus it’s too short when the waves get going.

A Chinese SoT item (left and right) typically has a 400mm blade and is quickly removed on the pivot pin, plus can be both retracted and deployed 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 (above) or the Gumotex kit.

MYO
While the rudder inched its way over from Hong Kong I came up with a rough idea to mount it on a chopped up HDPE 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 sort of swivel tube was needed, or just a built block of HDPE with 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 inflatable is tricky, but if my first ideas aren’t good enough, there’ll be better ways of doing it.

The way I chopped my 8mm 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 – copied 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
Having owned a ruddered IK helped with setting up the control lines. The threading of the rudder lift/drop 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 rather than cheaper paracord, but that’s easily changed if need be.

One 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). The bolt isn’t tightened and rolls as the rudder lifting cord passes under it.

The rudder pivot lines run smoothly through more fuel line slipped unobtrusively under the redundant splash deck tabs on the hull top (right and left).

At 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.

I found a plank of laminate flooring in the barn, sawed 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.

The 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 like you get on a stuff sack that will actually lock the slippery Dyneema cord, but doesn’t need tension like the cam lock cleats I used on my V-Sail. I ordered the wheel locks on the left which should work.

The 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 installment: Oh rudder, how art thou?

2016 Seawave with rudder option

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Seawave main page
My MYO rudder (MkII)

The 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, I was halfway through adapting a cheap SoT rudder for my Seawave (left) and the factory version (going for £200) 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.

For 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. I also believe they supply some stick-on velcro which goes behind (aft of) the black knob. Otherwise the plate would be prone to distortion under rudder forces, or give a mushy response like I got that on my prototype version.

The Gumo’s rudder’s retraction method is a pull-up-and-in, (left) whereas my was 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.

At 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 on the stern deck (right) which I added to my boat to make a straighter, drag-free pull on the lines.

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Tag Archives: rudder for Gumotex Seawave

Seawave 2: Kayaking the Sussex Coast

Seawave 2: Mk3 rudder (MYO)

Seawave Rudder MkII tested

Gumotex Seawave – MYO rudder

2016 Seawave with rudder option

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