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PostPosted: Thu Aug 24, 2017 6:44 pm 
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I have a 2017 Outback that I've been using very actively for three months. Today I noticed something unusual for the first time when I took it out on a calm day on relatively still water.

The rudder is in the down position for all of this. When I pedal, the kayak starts to veer to the left and I have to compensate by moving the rudder steering lever right. Once I stop pedaling and "coast", the kayak starts to self-correct and track to the direction indicated by the steering lever as it slows down. Start pedaling again and it pulls to the left again. It also felt like the kayak wasn't aligned parallel to the direction of travel. This behavior was present regardless of direction I was going in the water (I think this rules out currents). I checked the rudder as best as I could, and redeployed it multiple times (I've noticed in the past that if it isn't fully deployed it doesn't track properly). The MD 180 looks to be in good shape. Checked for bent mast rods, tension dial mismatch, or other misalignment and it looked ok. I eyeballed the bottom of the hull for any dents or irregularities and didn't notice anything immediately obvious. I have the larger sailing rudder installed.

At one point in trying to troubleshoot, I raised the rudder to see what would happen and the kayak started to do a very tight spin to the left (as if the rudder was down and fully turned left). I don't know how reliable this test is, since I also got it to turn to the right sometimes if I raised the rudder while turning right.

Would appreciate any tips on what to check that may be causing it to pull to the left. Thanks


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PostPosted: Fri Aug 25, 2017 7:57 am 
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You must use the cleat to lock it down – in the cockpit – near the bottom of the mesh pocket on the right side is a small black cleat – place the line in the cleat – that is what holds it down.

If it isn't cleated and lifts even a tiny bit it starts to turn left - as the rudder raises it flips up onto the deck towards the left.

With the rudder fully out of the water the boat would go in circles - yes, that is correct.

Most important thing - cleat the rudder down. You might think it's staying down but it can be lifting a little - which turns left.

The manual shows this on page 10 https://docs.google.com/viewer?url=https%3A%2F%2Fstatic.hobiecat.com%2Fdigital_assets%2Fmirage-kayak-manual-150828.pdf

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PostPosted: Fri Aug 25, 2017 8:32 am 
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I have been cleating the rudder. I learned to do that after about the second time out. I confirmed that while it was cleated that it was firmly positioned and resisted lifting. Anything else to check? I will also try putting the standard rudder back on to see if the one I'm using is damaged.


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PostPosted: Fri Aug 25, 2017 9:53 am 
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Is there a consistant lever setting that keeps the kayak tracking straight? If no, then there is probably too much slack in the cables. If yes then create slack on one side and take up with other to straighten. My inflatable kayak may be different, but I had to adjust a lot when new until the line lengths stabilized.

I think my lines are something like dyneema, which supposedly are super stable in length. In practice in other sports they can seem wildly unstable, especially when wet and under intermittent load. They may be prestretched by the makers, and this can reverse under use. Or they aren't prestretched and so they stretch. After some hours of usage they stabilize to a large degree..

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PostPosted: Fri Aug 25, 2017 12:46 pm 
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Given it seems to be worse when you actively pedal what happens if you paddle it? Try rudder up and down, included having the handle wedged in position? Is it turning one way or the other still dominant to same effect. Be aware of your tenancy to paddle more strongly on one side vs the other.

Ideally if you know someone else with a hobie swap drives to eliminate drive problems

Also find rudder position that holds it straight. Wedge in place, then hop out in shallows and eyeball rudders actual position.

Also try leaning substantially to either side and see how much that affects turning each way.


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PostPosted: Fri Aug 25, 2017 1:58 pm 
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mvc00134 wrote:
When I pedal, the kayak starts to veer to the left and I have to compensate by moving the rudder steering lever right. Once I stop pedaling and "coast", the kayak starts to self-correct and track to the direction indicated by the steering lever as it slows down. Start pedaling again and it pulls to the left again. It also felt like the kayak wasn't aligned parallel to the direction of travel.
There are a couple of possibilities:

1. Your fins may be biased to one side. To check this, hold the Drive upside down by the crank arms, with the front of the Drive pointing toward you so you're looking at the fins head-on. The fins should be straight up if the pedals are exactly together. If the fins are slightly split, that is no big deal, but if they are both leaning to one side slightly, the Drive's thrust could be off centerline. To correct this, you would ease cable tension for each fin on one side and take it up by the same amount on the opposite side until the fins are in-line with the crank arms.

2. With the Drive inserted in the hull and the hull upside down (perhaps on a pair of saw horses) look at the axis of the fins compared with the axis of the hull. It's rare but possible that this could be marginally off. In this case, there isn't much you can do about it. The rotomolding process provides some small individual variation in the boats during the extraction and cooling process that is unavoidable because of shrinkage. The operational result is negligible.

Quote:
At one point in trying to troubleshoot, I raised the rudder to see what would happen and the kayak started to do a very tight spin to the left (as if the rudder was down and fully turned left). I don't know how reliable this test is, since I also got it to turn to the right sometimes if I raised the rudder while turning right.
As jbernier says, the boat always turns left when you raise the rudder. This is a feature of the Twist N Stow rudder. I use this feature when coming to shore, pulling the rudder up just before landing to present the starboard side to the shore, which is where I exit the boat. Very handy!

You should know that all the Mirage Drive Hobies are directionally unstable in forward motion because they have no skeg. They will turn in either direction depending on the initial input; the shorter the boat, the greater the effect. The boats are directionally stabilized by the rudder alone. Not having a skeg gives the rudder more authority to turn the boat so you get better handling. That's also why the large sailing rudder works so much better than the small rudder. This is also why the boats don't track well without the rudder down and locked. Note that all Hobie paddling boats may look similar but they all have a skeg for better tracking.

To that end, It's always good to check your directional rudder lines -- they should be taut (but not tight) when the rudder is down, locked and pointed aft. If there is slack in that position, the boat can wander, causing frequent corrections. Since the hulls expand and shrink slightly due to temperature, it's good to check this during the seasons as temperatures change. It's easy to adjust the line on the appropriate side with a Phillips head screwdriver. The rudder line itself is made of Spectra, quite strong and very length-stable. 8)


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PostPosted: Fri Aug 25, 2017 7:01 pm 
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Roadrunner wrote:
The rudder line itself is made of Spectra, quite strong and very length-stable. 8)

Sorry to nitpik, but I have a grudge against spectra. It's length is subject to (1) permanent braid elongation when the weave compacts under first few tensions, which occurs on all ropes regardless of composition. http://www.samsonrope.com/Pages/Demysti ... Creep.aspx Maybe Hobie stuff was pretensioned to take care of this, but to my eye it develops that flattened skinny look that I observe in other applications. I dunno how much.

Spectra and it's near twin dyneema is subject to a lot of (2) creep, like 3% ,which could translate to a couple inches on rudder lines. Some would argue that creep only occurs from lengthy sustained tension, but http://www.samsonrope.com/Documents/Tec ... 12_WEB.pdf explains why to consider going to a better grade of dyneema::

Quote:
THE PHASES OF CREEP
The creep process of synthetic fibers has three distinct phases; In phase one, the rope undergoes rapid elongation (a few percent) immediately after the load is applied and may continue this rapid elongation from a few minutes to a few hours.

Spectra is under competition by the chemically identical Dyneema which has various production swizzles to reduce (3) stretch. West Marine line selection guide https://www.westmarine.com/WestAdvisor/ ... ng-Rigging confirms "Spectra-Dyneema-HMPE has the highest strength-to-weight ratio, low stretch, and impressive maximum working loads." but notes the moving target within dyneema:

Quote:
Newest, strongest, lowest stretch, and with nearly zero creep are Dyneema lines made from a variant called SK-90. It stretches 10-15% less than the most common type of Dyneema, SK-75, and is also 10-15% stronger.

Now all this may be superceded by some new version that Hobie uses, but on the other hand spectra/dyneema is considered too unstable in length by some for top sail racing and archery applications (small additions of vectran may be added). My slight experience on the one i12s has suggested initial stretch followed by stability after a half dozen outings.

Want more personal experience? I have owned about a dozen paragliders with either kevlar or spectra lines, and I just HATE spectra... hate it! It is so friggen unstable in length that the aerodynamics get perceptively messed up over time. The official remedy is to go and stretch each little line to a constant tension, because the little weak tensioned cross lines lines near the top have not been stretched out by your weight like the longer ones. I love the stability of kevlar even tho it is brittle and may break and unzip me into freefall.

Paraglider mfr web pages talk about the shrinkage rather than stretch of spectra/dyneema because theirs are prestretched. http://www.up-paragliders.com/en/conten ... ter-to-you "Initially all lines will tend to shrink equally – but as soon as a glider with shrunken lines is taken out for its next flight, the A and B lines, which carry much more weight than the C lines, will return to their original length, while the C-lines will remain too short and bring the glider out of certified trim." "One way to have your cake and eat it is to employ sheathed Aramide/Kevlar for the thicker, lower lines, and Dyneema for everything above the first bifurcation. This is due to the fact that the total length of the shorter gallery lines isn't affected as much by, say, 0.5 percent shrinking as the longer, lower lines," "The issue with Dyneema is not strength, it is shrinkage, and that happens irrespective of line diameter."

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PostPosted: Mon Sep 04, 2017 11:19 am 
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Thanks all for the help. I tried swapping out the rudder for the standard rudder and there was no difference.

When I got home where I could put the kayak up on sawhorses, I saw that the rudder didn't look like it was tracking straight with the lever in the straight position. After adjusting the rudder lines with the two screws at the back, it seemed to help a lot. I was able to get the steering to feel like it used to. It took a couple of cycles of adjustment followed by testing in the water to get it right. I'm not sure if it was because of the line stretching a little bit after 3 months of hard use (as a newbie I tended to make mistakes such as dragging and banging the rudder). Also I took it in rough water a few times and if the currents were forceful on the rudder, may have helped contribute.

All good now though.


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PostPosted: Mon Sep 04, 2017 8:40 pm 
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mvc00134 wrote:
When I got home where I could put the kayak up on sawhorses, I saw that the rudder didn't look like it was tracking straight with the lever in the straight position. After adjusting the rudder lines with the two screws at the back, it seemed to help a lot. I was able to get the steering to feel like it used to. It took a couple of cycles of adjustment followed by testing in the water to get it right. I'm not sure if it was because of the line stretching a little bit after 3 months of hard use (as a newbie I tended to make mistakes such as dragging and banging the rudder). Also I took it in rough water a few times and if the currents were forceful on the rudder, may have helped contribute.

Hobie's Twist-n-Stow Repair Manual, which is available at https://static.hobiecat.com/digital_ass ... 1504278546 , indicates that the steering control on a Hobie kayak should be adjusted so it is centered in its range of motion, not pointing straight ahead, to make the kayak track straight ahead. Specifically, the manual says "With the tiller (control handle) centered in its range of motion, the boat goes straight. Note: typically the 'centered in range of motion' is actually pointing to the right at about 20 degrees." Later in the instructions, the manual says "Center the steering control handle in the middle of its range of motion. This is typically when the control handle is pointing 20 degrees to the right."


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PostPosted: Mon Sep 04, 2017 8:46 pm 
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Quote:
Hobie's Twist-n-Stow Repair Manual, which is available at https://static.hobiecat.com/digital_ass ... 1504278546 , indicates that the steering control on a Hobie kayak should be adjusted so it is centered in its range of motion, not pointing straight ahead, to make the kayak track straight ahead. Specifically, the manual says "With the tiller (control handle) centered in its range of motion, the boat goes straight. Note: typically the 'centered in range of motion' is actually pointing to the right at about 20 degrees." Later in the instructions, the manual says "Center the steering control handle in the middle of its range of motion. This is typically when the control handle is pointing 20 degrees to the right."


Yeah, I figured that out the hard way too, thus the multiple trip/alignment sessions. My first attempt was to align it straight ahead and that was a mistake. Nothing was harmed, and I learned a bit about rudder alignment in the process.

Thanks for pointing this out.


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