Cuss, Cuss, Cuss

I finished the 42 mile Phatwater Challenge kayak race this weekend in an Adventure. After spending money to replace worn parts and lubing up the pedal drive unit, I was all excited about finishing in under 5 hours which is something a pedal boat has yet to do in that annual race now in its 10th year. 15 seconds into the start of the race, the chain cable on the drive unit broke. Very bad timing for a pedal drive unit failure. The redesign of the mirage pedal drive did NOT solve the problem of cables snapping. Talk about losing confidence in a product...

People ask me why I carry a spare drive unit and I tell them bluntly, "The Hobie pedal drive unit is so unreliable and prone to breakage that I have to carry a spare."

As the race got underway, I swapped out drive units and ended up starting near last place as everyone passed me while swapping units. Cuss, Cuss, Cuss!

Solution to fix the cable snapping problem that should have been addressed long ago: Seal the cable ALL the way to the crimp to stop the corrosion because the cable only breaks where it is exposed to water.

Congratulations on finishing first in your division and finishing within 7 min and 35 sec of being the first pedal boat to finish in under 5 hours. In my book quite a accomplishment for a senior citizen considering funds spent on worn parts and the lubing you had to do. Had that drive chain cable not broken, resulting in the 7 min and 35 sec change-out, I am sure you would have been the first under 5 hours.

_________________
I'm right 98% of the time. The other 3% I don't worry about.

Rnykster:
Have you ever driven past a bridge with cable supports and not seen people working on the bridge, thats what they are doing is maintaining mostly the cables, if moisture gets into them it's just a short matter of time before they fail. Even with stainless alloys if water is allowed to sit around the cable it will corrode and fail very quickly. It all comes down to maintenance. On some of my older Mirage drives I noted the corrosion on the cables, and when I bought new drives I took some automotive touch up paint and filled in the cable ends so they are sealed as good as possible. I also always rinse off the drives when done and make sure I spray them down with WD40 to remove any moisture. When the cables are kept clean and dry they seem to hold up fine (stress wise). If they are not maintained, then this is the weakest point to fail first in my opinion. Since you are using these parts for racing it would probably be a good idea to replace the cables on a regular basis or at the first sign of any corrosion.
For racing you might look into replacing the standard stainless cable with custom designed and built Kevlar cables (probably 3x stronger than the steel cable), if you go to West Marine, they have some incredibly strong low flex rope (like spectra (which is 3-4x stronger than steel cable)). It's a pretty straight forward design task, and I'm sure you can get them custom made at any fabrication shop who specializes in that kind of stuff. There are plenty of design experts on the forum who can offer more suggestions. I've never had a cable fail myself, and havn't heard of any others failing but then again I'm not using them in competition.
I think regular maintainance is the key here, when taken care of properly most of this stuff lasts for many years even with heavy regular usage (excluding competitive racing of course).
Congrats on winning though.
Hope this helps
Bob

Thanks for the tips Bob.

For what it is worth, I don't wash my car after every time I drive it even though I live in a saltwater environment. The car came with a 3 year warranty and includes a longer warranty for the drive train - the parts that take the most stress. Nothing has broken on it in over three years.

It should not be my responsibility to upgrade components to withstand salt water for a product that is built to be driven in salt water. If Hobie can seal 95 percent of those cables with a rubber coating, they can figure out how to seal the remaining 5 percent where the corrosion is occurring.

PS - I use the recommended WD 40 on a regular basis.

Thanks Ranger. They created a pedal-boat division after the race because the pedal boat also beat all the plastic and composite kayaks between 12 to 17 feet, which was the way the organizer originally classified the Adventure as. It Adventure is only 16 feet long and quite wide at 27-1/2 inches, but in reference to races, there has been discussion around here of the unfair mechanical advantage a pedal boat offers compared to a regular paddle kayak. A tandem pedaling team came within a minute or two of breaking the 5 hour barrier a few years back. River levels affect current speed and this year the river levels were low and there were significant headwinds during the race.

Congratulations! Never heard about that kind of speed in an Adventure!

42 miles = 67,6 km in 5 hours 7 min 36 sek ???
Did I get it right?
Keeping a speed over 8 Mph for over 5 hours?
You must be really fit!
Are you using both paddle and Mirage drive at same time?
Any other secrets? How fast is the river running?

I take my hat off for you!

thomas in Sweden

A bit confused... I take it that this cable was not new by the look of it, so how old do you figure that this specific part was?

Cable failure has dropped significantly since our change to the V2 drive components. Any coating that is subjected to flex and stress can actually end up trapping moisture inside against the cable. This type of failure is typically related to the stiffness of the end fitting. It is a hard point. The V2 design minimized it, but crimping the end fitting. Twisting the cables... repeated cycles of stress all cause wear on the parts.

You are a particularly hard user as noted by some many of your posts over the years. While we learn for this type of experience, a vast majority of users will never break a cable.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

Thomas, I was amazed by the speed too!

However, from what I am reading this race seems to be run on a river.

I am only hoping that the competitors are actually pedalling with the flow, not against it. If I am wrong in this respect then I am giving up Hobie kayaking altogether and I am going to take up carpet bowls instead

I used the new drive unit 10 times last year starting in May so that would make it less than a year and a half old.

Yes, overall average speed was a little over 8 mph which is slow because river levels were low at race time. The river current varied between 1 and 5 miles per hour depending on the width of the river. Yes, I pedal and use a paddle at the same time during the entire race. Using the paddle while pedaling boosts the speed up about 0.5 to 1 mph. Without the aide of current I normally pedal and paddle maintaining 5.3-5.5 mph and it is a good way to develop aerobic fitness. When I first started out trying to paddle while pedaling, I couldn't maintain it very long without becoming winded. No secrets - just keep doing it and it will become second nature.

Well I was thinking the same, maybe take up knitting or something.

@Rnykster
Well it is still an amazing speed! My hat remains off!
Very interesting that working with additional paddling gives that much. With only pedaling I can maintain about 4,6-4,8 mph for 2-3 hours. I am not so fit right now but with some training I expect to prolong that time to 5-6 hours. If I can (with paddel) get up to an extra mph that would be very nice!

I will participate in a 62 mile race (2 days) around an island next summer and I will most probably be the only pedal driven kayak in the race. I will have no chance to win but maybe the other kayakers will see the Hobie with a little more respect if I perform well. That is what I am training for. So if the Mirage drive don´t breaks and my body also works OK...

BTW If you are using the paddle at same time that must take some stress from the pedal drive?

About the cable (and the chains), I have read somewhere in the forum, that slightest sign of wear and defects in wire (or fittings) calls for immediate replacement.

How long time can you keep 5.3 - 5.5 mph?

BR thomas

The only kayaks around here that can beat the Adventure in a race are surf ski boats, so whenever the Adventure is classed with regular plastic and composite kayaks, it usually wins, so instead of saying you have no chance, you should be saying, they will have no chance.

I can keep up a 5.3-5.5 mph pace for 5 hours - just did it.

Sadly, I've been informed that by going that fast, I'm abusing the kayak and taking it to extremes. Do NOT race the Hobie pedal boats - they cannot withstand regular use. Revert to standard fins because use of ST Turbo fins causes failure of parts.

Have fun.

Well there will plenty surfskies and also very fast kayaks.
And there will be excellent paddlers in all, so there is really no chance of winning the race.

I don´t know if I will reach your speed and stamina but I will try.

As for the ST Turbofins and racing I know that, much more stress will effect the kayak. The only thing that worries me are damages to the hull. Hobie hulls are hard to repair correctly. Especially the drive well were all the force is transmitted from the Mirage drive to the hull. The Mirage drive contains a lot of replaceble parts - no problem. When I was racing with sailboats all the breakdowns and damages occured during races. That is part of the race to prepare the boat so materials will last during the race. Costs money and includes parts to be replaced more often.

Keep on racing! (mayby you can get sponsor help from Hobie!)

thomas

Sadly --

There seems to be a disagreement on the post as to the definition of "regular use", "extreme use" and "abuse".

It is questionable that 5mph + for 5 hours can be defined as regular use. Unlike other Hobie products I believe the kayak line was designed for recreational use. While racing is a recreational use for some, the drive system was designed foremost for efficiency and not high end racing durability. I doubt that most users want a high end system.

"ST fins cause failure of parts " I personally have not found this true. I live on the flats in oyster-bed country. Very seldom do I come back from a trip that I don't have to remove the shafts and fins, straighten them and mend the fins. Amazingly never have I had to replace a broken shaft. The above daily damage is my fault.

"Abuse" Constant speed of 5+ can not in itself be described as abuse. However, how one gets to that speed may. Quick sprints to speed could well be abuse. My tires are warrantied for 60,000 miles and good to 100 mph. However if I burn them out every takeoff they are not going to last 60,000 miles. If I chose to recreate with my Adventure in 6 foot surf and bend it in half. I can't blame the failure on Hobie.

"Overview" A great deal of the post on this site deal with problem solving. One only has to present a problem and several will reply back trying to assist. Many, such as Roadrunner have far exceeded assistance and developed new methods and materials. Additionally, unheard of with most products, Hobie Representatives are on the post to assist and answer questions when they arise.

Rnykster - I am sorry to see you go.

Having Fun

Rnykster :
Now you are just getting annoying making a statement like that. Myself and others gave you many very good suggestions on how to get more out of your mirage drives from a design standpoint (for racing purposes). We didn't have to do that, we did it because we are trying to help you here. As with the shafts it's the physics of the metal, you can only get so much stress out of a 303 alloy (17-4) before it fails. I suggested that you go to a 414/420 heat treated alloy for racing, which should hold up better to the extreme bending moment that you are putting onto the drive. However this material would not be suitable for general use because if someone were to hit the bottom while pedaling the rod would break and not bend. In addition because of the high iron/carbon content the rods would have to be PVD coated (which is expensive) in order to prevent corrosion. Think about it with the force you are putting on those shafts I would expect the ends to be flexing 2-3 inches on each and every cycle, there is no 300 series stainless out there that will not fatigue out in a few thousand cycles under that much stress. Hobies selected materials are the best fit here because of corrosion resistance, crash forgiveness, and cost for general use by 99.8 percent of us. When you have your heat treated shafts custom made I would expect them to cost a couple hundred each. For competitive racing thats very reasonable.
I once had the pleasure of spending a week with Lance Armstrong (before he was super famous) we were working a design engineering show where a couple of his racing bikes were on display and he was doing demonstrations, signing autographs and stuff. The 3D CAD system I helped write was used to design his bikes. The point is those bikes cost a quarter million each to design and build. I doubt if they were ever made available on the Walmart bike racks.
This is all high school level engineering. Below is the FEA analysis results of your problem.
This first chart is the current shaft with 15 lbs side force applied to the side of the shaft. The shaft flex's a around 2 inches (you can duplicate my results by putting the shaft in a vice and pulling on the end with a fish scale, or hang a bowling ball on the end.)


This slide shows a 414 stainless hardened shaft, the yield strength is still exceeded but not by as much


The next slide shows a titanium alloy shaft with a much higher yield strength (155k), and the FOS (factor of safety) is over 1, but will likely cost you a thousand bucks to have made. (part of the reason why jet engines costs $12 million is the materials)

We should put it to a vote. Should Hobie add $3,000 dollars to the cost of a Tandem island (4 shafts) so Rnykster can further his racing career. I vote no.
My opinion is your statements are unfair to Hobie who goes out of their way to design a very well engineered and good product for general use, and I personally take offense ( I have no affiliation with Hobie Cat company, I'm just a happy user).
Who wants to see Rnykster continue racing Hobies, I'm a big fan and vote yes.
Bob