Drive Unit, Spare Parts, and Tips

Roadrunner,

Did I forget to mention in a post before the holidays that I have been using turbo fins from day one on a 2007 model Adventure?

I've been seating the top of the fin about 1/8" into the outhaul and it's been working well. However, if I understand your recent post the criteria is not a static seating depth in the outhaul (top of fin to bottom of outhaul channel), but the minimum amount of freeplay the fin has on the mast without contacting the outhaul. Just to clarify: I should tighten the adjustment screw such that when I slide the fin up the mast from its static (or lowest position) position, it has a minimum of 1/4" upward range of motion into the outhaul without contacting the outhaul?

I've been out of town but will check this this morning. It may just be that my ad hoc 1/8" adjustment affords this amount of freeplay (or more) unintentionally. Hmmm. Or, the fin may be too loose and allowing too much mast flex which may have lead to metal fatigue?

Thanks RR.

Hi Dennis,

The 1/8 inch is just a gouge that seemed to work best with the longer (original) masts. So it made a good reference point for anyone who didn't have the time or patience to work it out for themselves. The actual performance though, is determined by the leach tension, as established by the adjusting screw.

The 1/4 inch slack is somewhat of a ballpark figure since you can force more or less movement by stretching the rubber. More specifically, I target about 3/16 inch of slack (without stretching). Depending on the length of your masts and whether they are fully seated, this could give you a different gouge.

If you have the patience to test your speed at, say 1/8 inch intervals, you may find that the optimal position for you may be a little different.

The way I did it was to tighten the leach until my top speed dropped, then back off and verify the higher speed. When I loosened the leach too much, it felt like the fin was blowing out or losing its bite under full acceleration.

Theoretically, you might optimally use different tensions for different speeds. This seems to be a bit impractical though. I tend to tune mine to maximum speed, though it may or may not be the most efficient for extended cruising. The reason -- if I'm trying to catch a boat wake or get somewhere in a hurry, I need all the help I can get!

Thanks RR,

When the weather clears up I'll experiment with different leech tension settings. My aft fins already exhibits signs of stretching along the leech. Whether this stems from too tight leech tension or is a consequence of my moose routine on the pedals is uncertain. I suspect the latter as the fin has never been seated more than 1/8" into the outhaul, static setting.

BTW, do you have any thoughts re lubing the turbo mast specifically to reduce friction or ease movement associated with this sliding? There is a thin WD40 film on all the surfaces of my Mirage drive for corrosion protection purposes but I have some specialty lubes in the shop that won't eat rubber and are superior friction reducers.

Wear reduction and efficiency of the sail are the larger issues I suppose. The range of motion and level of twisting involved are pretty minimal so heat in this water cooled mechanism isn't much of issue.

Thanks for your insights and advice.

Water soluable lubes would be flushed out. Non-soluable lubes may end up retaining particulates and causing more wear.

About the only thing I can think of is to polish your mast, but I don't think it would make that much difference. Water itself is probably your best lubrication from a practical point of view!

Yes, I am new to this forum. I just got my Hobies and have not even been out to the water (ice) yet. I've been trying to following along the entire thread of this discussion, and now I have a quagmire (indian for problem?). What is a leach/leech? I've seen the term thrown around, and following Hobies newest listing of how the drive works, (http://www.hobiecat.com/support/pdfs/Mi ... _Parts.pdf) I see no mention of a 'leach'. -So, I give up... what is it????

Also. As far as lubricants go, I am in the power equipment business, and WD-40 is generally the lamest of lubes to use-especially with snowblowers. CRC's PowerLube works great if you can find it. I'm sure everyone has their favorite lube, but we find that WD40 just washes off too quickly for us... so I can only imagine what it does/doesn't do for kayaks in water. As far as grit retention, I would not think that holding grit is so much an issue as to keep me from using lubrication. (Anybody here ever ride a dirt bike?)

This site has been extremely valuable to me. Thanks everyone for all your 2 cents.

Now, if spring would just hurry up and get here...

-Steve

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Jack of many trades.
But you can call me Steve.

Ahoy Steve and welcome to ye forum!

Hobie, having been caught up in the sailing business for so many years, took a look at the Mirage Drive fin and decided it was just like a sail, except for the fact that it was "upside down" and in the water. So the nomenclature for the fin assumed that of the sail.

To review, the three sides of the modern sail are named luff (forward side), foot (bottom side) and leech (back or "aft" side). The three points on a sail are described as the head (tip), tack (bottom forward corner) and clew (bottom back corner).

So when you see that the clew adjustment tensions the leech, that means the screw in the back of the (optional) Turbofin can be screwed in to tighten the back side of the fin (or sail).

Now, when you see the term mast (metal rod that supports fin) and outhaul (where back of fin attaches to the Drive frame), it will all make sense, right? Don't feel bad; I have to look it up myself all the time in the sailing encyclopedia!


I'm no expert on lubes, but WD-40 may not be as useless as it appears. If the WD-40 is employed after the fins are used, it is pretty good at chasing moisture and preventing corrosion. The fact that it quickly dissipates in the water is of no negative consequence. The water itself is an adequate lubricant for most parts; the main bearing surfaces are greased with a marine lube.

Please correct me if I'm wrong, but "standard" oil is not a good choice for
motorcycle and bicycle chains for the very reason that it attracts dirt and accelerates wear. Chain lube, on the other hand, is an oil/wax combination that lubes, coats and seals the chain to keep dirt, grime, etc away from the wear points.

Depending on the circumstances, turbid, muddy waters contain suspended particles; surf conditions and "beaching" the fins expose them to sand. These particulates can stick to petroleum products and grind away at unsealed bearing surfaces, whereas they would tend to flush out otherwise with water. Those who have had military weapons training learn right away that oil left in actions is an excellent way to jamb weapons because of power residue and dirt that can stick to the lube!

Just my opinion.

Now I know why I never took up sailing. I'm "clewless"!

Powerlube by CRC was formerly called '5-56', but I guess it lacked the sales appeal, and it was renamed. It is a great penetrating lubricant, and it not only displaces water once, it keeps doing it. I don't think it would attract grit/dirt any more or less that WD40, it is about the same viscosity.

Anyway - thanks for the terminology. I guess I'm even more 'green behind the gills' than I thought! My background is in electronics, mechanics, and sales. Far from anything relating to sailing. (I got a leech stuck on me once, does that count?)

-Steve

_________________
Jack of many trades.
But you can call me Steve.

Oh yea. I spent 4 years in the Army -- electronics. We didn't spend much time on the range - but one thing I do know: if you don't keep your M16 lightly lubed - it will rust. And the Sarge hates rust. And I hate pushups.

--It's amazing what you learn in bootcamp at 17yrs old, and still remember when you are 45! Now if I can just find my glasses. Where'd I put them!

-Steve

_________________
Jack of many trades.
But you can call me Steve.

Hi...

I'm another new-Steve-to-the-Forum, and hail from Camano Island, Washington where I have spent most of the last decade working on the Microships (a pair of amphibian pedal/solar/sail micro-trimarans). Now, I have a Corsair 36 trimaran named Nomadness, and just bought a new Revo with sail rig, since I need a fast and capable kayacht to carry on the mothership as an alternative to the poky-but-functional dinghy. I've had the Revo a week now, with one outing of about 8 miles, and am impressed... just sold my trusty inflatable touring kayak.

Anyway, I should save all that intro for a fresh thread; mostly I'm replying here because I have a yet-unopened turbofin kit (72065) and have been assimilating the discussion about evolutionary developments in the Mirage Drive... and the effects of the higher turbo loads. I pedaled 17,000 miles around the US on a computerized recumbent bicycle, but that was a long time ago (*creak*)... so I don't think I'm as likely to overpower them as some folks here!

Regarding the WD-40 question, my eyebrow raised at that recommendation... it certainly isn't known as a lube so much as a "water displacer" (hence the WD in the name). This may be exactly the intent, though, so before getting experimental and risking plastics with a succession of exotic chemicals, I thought I'd inquire of the gurus here if there has been any experimentation with Boe-Shield, which I use and respect for general corrosion-inhibition applications. My kayaking environment is almost entirely salt-water, so I want to maintain this properly right from the start (since, as the old saying goes: Water corrodes. Salt water corrodes absolutely.)

Thanks to all of you for the high-quality discussion... and to Hobie for listening to your user population. That combination was one of the strongest factors in my buying this boat.

Cheers,
Steve

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2017 Tandem Island; projects described at microship.com

Hi Steve and welcome to the forum.

Your experience with Boeshield T-9 sounds pretty tried and true. If you're storing your drive aboard the boat, this should make a great test environment for the equipment. I'll be anxious to learn how it works out!

When you get those Turbofins installed, after running around with the standard fins for awhile, I think you'll be very pleased!

For those of us tho haven't had the pleasure of getting acquainted with some of your fascinating work, perhaps this will serve as an introduction:
http://microship.com/resources/harsh-en ... -aprs.html

Wow, its a small world. A long time ago I keenly read the episodes of your recumbent travels as I dreamed of an extended cross country cycling trip. Even bought a recumbent years later. It now sits gathering dust because I much prefer pedaling on the wide open water ways. Since buying a Mirage, I've forgotten all about road grime on the legs, flats, sore arms and butt, dogs, headwinds, cars, horns, curbs, potholes, rocks, glass, intersections, red lights, rude drivers, etc. Thanks for bringing back those memories. It is good to see you joining the discussion Steve.

My brand new drive unit came packed with a white lithium grease. The dealer I bought from said to use nothing but silicon spray on the drive units. I've recently examined the wear and tear of the drive components and find the composite sprockets to be solid as a rock with no signs of internal wear. However, the metal shafts are being eat up by the grit in the water and rust. Maybe WD40 is recommended to displace the water from the metal components to prevent rust? It also my understanding that water acts as a natural lubricant between the composite sprockets and the metal shafts. Some people recommend just rinsing off the drive units after each use.

Never heard of Boe-Shield. An inventor I talked to recommends "Corrosion Block" for components exposed to saltwater, but I've never used it.

I keep praying for drive system incorporating sealed bearings that will not corrode in saltwater. If boat motors, shafts, and propellers can sit in the saltwater for ages, that proves there are parts and materials that can handle the saltwater elements. Meantime, I'm following the latest recommendations from Hobie by using WD40.

Your best bet would be to encourage some Hobie engineers to join the thread of component care.

Roadrunner and Rnykster - thanks for the kind welcome! It's good to be here, and I'll probably post soon about some of the mods and general geeking-out of my boatlet. I'll be maintaining a page of short technical articles over yonder as the project develops.

Thanks also for the comments on the corrosion inhibitors. The phrase "petroleum distillates" on the Boeshield bottle sent me scurrying off to their website before dribbling it willy-nilly onto uknown plastics, and in their FAQ they say it won't damage fiberglass (presumably including the esters and epoxies), has a paraffin wax base (no silicone to render future adhesion impossilbe), and won't harm paint. Sounds good... but then I read this in response to a question about dispensing with a Windex-style spray bottle: "Keep in mind that Boeshield® T-9 is solvent based and most pumps will not last if left in it for long." I found the MSDS... there's a barely readable PDF copy here:

http://intranet.risd.edu/envirohealth_msds/BoeshieldT9.pdf

Presumably in our application we are not worried as much about this, as the carrier will mostly evaporate, but I'm a little wary of letting it find its way into tight spaces between plastics where there may not be enough airflow to vaporize it in a timely manner. For now, I'll hold back until I hear from a Hobie engineer. (I think the same issues may come up with WD-40, so perhaps it has already been dismissed as a non-problem.) For reference, WD-40 is mostly mineral spirits (Stoddard Solvent) and mineral oil; its MSDS is in this PDF:

http://www.wd40.com/Download/?/Brands/pdfs/msds-wd40_aerosol.us.pdf

I'm hesitant to let any of this stuff sit wet on plastics for long; has any life-testing been done in that mode?

Cheers!
Steve

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2017 Tandem Island; projects described at microship.com

The Drive Unit -vs- Turbo Fin saga continues...

This is depressing. It is no longer any fun kayaking in the Outback. Hobie, Hobie, Hobie - what do I have to do to get a drive unit that works reliably with the Turbo Fins?

This morning I had favorable current in a deep water river and was pedaling at a nice easy speed (heart rate about 85-90) when the drive unit SPROCKET split through the set screw area as usual (see below photo).

So far in 2007, the Mirage Drive has broken on 50% of my kayak trips. Replacing a broken sprocket with a similar sprocket, that at least from my experience, is CERTAIN to break, is not fixing the problem - that will only guarantee Hobie bad publicity from frustrated owners. However...
However, if Hobie sent out replacement parts that provided a REAL FIX, Hobie would get good publicity from happy owners. (HINT HINT) Do something to FIX the problem instead of exacerbating it.

Hobie advertises the ST Turbo Fins will add a 10% increase in speed. For what it is worth, I noticed about a 30 percent increase in speed with similar effort level. Having acclimated to the Turbo Fins, I do not want to go back to standard fins. I'm like a junkie, waiting for a fix...

Perhaps a set of stainless steel sprokets? At least they won't crack!

Hey Rny and RR,
Don't forget that according to Matt Miller, Hobie is finally seriously looking at going "retro" and will be re-introducing the SS sprockets and mast holders that several of us have been harping on for many months. My first post on this was "older is better" back in 2 June 2006 or thereabouts. At that time, I think most of us hoped that the broken mast holders were just an isolated occurrence, but as more and more "power users" have opted for the Turbo fins, the problems with the plastic mast holders and SS set screws have compounded.

Anyway, Once Hobie can get its contracts let and production resumed on the SS parts, perhaps a SS repair/replacement kit will keep folks with the newer drives happier, not to mention safer!

Matt Miller commented in Aloha Dan's thread of 23 Feb. 2007 as follows:



http://www.hobiecat.com/community/viewtopic.php?t=6261

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