How can this happen?

Back with another question about my new-to-me '03 Outback.

I had a friend try out the boat to see if he liked it. He was only in it for 10 or 15 mins and came back saying he liked it but that the one peddle only went so far forward all of a sudden.

I had trouble getting the drive out of the boat and when I did I see that it's like this:


Note that the peddles are aligned but the blades are perpendicular. The one blade seems to have gotten "displaced" on the chain somehow. I've looked at it and there seems to be not near enough play in the chain for it to jump the sprocket and I can't see anything broken or bent. My friend says he didn't hit anything or have any other mishaps...I keep staring at this thing trying to figure out how this could happen.

I can see how to fix it. Just loosen the chain, turn the blade and re-tighten the chain. But I need to know the cause. I don't want this happening when I'm "out there" somewhere.

Am I missing something obvious or do I need to call in an exorcist?

The exorcist won't have the correct tools for the job...

Sounds like the friend was pushing to hard and the chain slipped.

He had no experience to know how hard he was pushing.

Don't over tighten when moving the chain back to where it belongs... The looseness is to protect breakage of the drive... Just my 2 cents worth.

Good luck with the fix.

one note i do not believe that mirage drive goes with a '03 Outback (might be wrong though)...thats a much older drive with the stainless steel sprockets. these sprockets will slip alot easier than the newer plastic sprockets. as long as the teeth are not broken on the sprocket...its easy enough to realign. do not over tighten the chain assy.

I adjusted the chain but I still find it hard to believe that a human could overpower this mechanism so much as to make the chain jump. Especially when the blades are offering no more resistance than water could provide. Maybe he had buried the blades in mud, but still it's hard to imagine it slipping before something broke. Guess there must be more stretch in the cable than I'm imagining.

Is there a place to view/download an online owner's manual for the older models? It would be interesting to know if this is not the original drive and I'd like to know if there's a measurable way to determine how tight is too tight for the chain assembly.

For now I'm going to start carrying a 7/16 wrench and my needlenose vise grips with me when I take the boat out any distance. (They don't make it easy to hold the cable from turning when trying to turn the adjusting nut)

Thanks for the help!

If the sprockets are stainless steel then, as others have already said, the chains do have more of a tendency to jump over the teeth which is what appears to have happened to your drive.

They key is correct tension in the drive cables - in my experience it is important not to overlook the "idler cable"; this is the one that goes over the wheel at the front of the drive. On these stainless sprocket drives if there is not sufficient tension in the idler cable (as well as in the chain cables) then there will be a pronounced tendency to skip a tooth if pedalled too forcefully. In this event the front chain cable is the most likely to jump a tooth so pay more attention to getting the idler chain and front chain tension right & you should be fine.

Apparently the reason for the skipping is that rapid pedalling creates some whiplash in the chain which lifts the chain over a tooth. If you look at the middle tooth of the plastic toothed sprockets you will see that the tooth has a "crown" on it - I believe that Hobie might have found it too tricky to cost effectively create this crown shape in stainless but was able to mould it in plastic... but that is only me guessing. Anyway, the plastic toothed sprockets have a far lower tendency to skip.

Now a shameless plug for stainless sprockets:

Do not be put off your stainless sprockets though: they work perfectly well if the cables are correctly tensioned - I have a stainless drive with many years of hard use on it and it is still going strong and perfectly OK.

There is more sloppiness of the masts in a stainless drive but that does not seem to materially affect performance.

And (BTW) it is possible to skip-back a tooth by pedalling hard on the opposite stroke to the stroke that caused the skip - I managed this one one occasion before I sorted out the need for idler chain tension.

But the big advantage (in my opinion) of the stainless drives is easy maintenance:

If for whatever reason the pin falls out or wears through (it can happen) and the mast falls out, it is cheap, quick & easy to replace, or "bodge". I now carry a spare pin or 2 after I had to bodge a lost pin with a fishhook once as a get-me-home repair.

The masts can be quickly and easily swapped out at sea in the event that a mast breaks or gets bent - this is not the case for the other drives which use a threaded screw or threaded shaft to secure the mast in the drive rather than the very simple split pin of the stainless drives. If the fin-mast snaps or bends on a stainless drive, remove the split pin and the mast or the stub just drops out: try getting a broken mast-stub out of one of the other drives at sea (well-nigh impossible) and you will begin to appreciate the simplicity of the split pin approach!

Please note though, that broken fin-masts are only likely to be an issue if you pedal long and hard after upgrading to the ST Turbo fins which use longer masts which are therefore more prone to fatiguing and snapping off; if you stay using the "normal" fins (as shown in your photo) or the ST ones (both go on the standard-length masts) then you are not likely to experience many/any fin-mast breakages unless you bash your drive or fins into hard objects or beaches.

So:
1. Tighten up (but don't over-tighten) your cables including the idler cable and the tooth skipping problem will go away once you have got the tension right.
2. Carry some spare split pins in case the pins wear out on the water (I suggest you drill some push-fit holes to carry the spares through the plastic "grid" on the reverse of the centre hatch cover and push some spares through so that they are always to hand and don't fall out into the boat).
3. If you upgrade to ST Turbos and want to thrash the drive, invest in some spare fin masts and carry a spare in your boat along with the spare split pins if you are venturing too far to be able to paddle/sail back in the event that a mast snaps on the water (likewise you can use some light line to tie the spare mast - via its split-pin hole - to a small hole drilled into the centre hatch flange so that the spare mast doesn't slide off out of reach inside your boat - just snap the line to release the mast).
4. If you end up having to do drive maintenance on the water take HUGE care not to let your only spare parts drop as you work - they will bounce and skitter on the plastic and invariably find a scupper hole or the empty drive well... can you detect the emotion in these words ???!!
5. Enjoy many years of happy and safe service from your stainless sprockets (but in the event that you really feel it necessary to change to plastic these parts are available from Hobie)

Thanks for the very complete answer Stobbo! I finally got Hobie on the phone and talked to a technician. I got the idea that I needed to tighten the chains more. So I tightened them more and took it out this morning with a couple of tools in my possession.
I decided to test it out there and started peddling hard and I felt the chain jump teeth. So I pulled the drive and repaired it while floating. It was awkward as the wind was up and it was a little choppy but I managed it mostly. I didn't get it exactly right but close enough and I didnt' want to go thru the process again on the water. (I couldn't find my needle nose vise grips which should make the process easier)
I now need to figure out if I need to tighten it more or if the sprocket/chain is worn out. Given that the guys at the local dealer didn't seem all that familiar with the '03, I'm not sure how to tell that short of sending parts to Hobie or just keep tightening and testing.

Will I damage something else by tightening too much or does it just make the drive work stiffly?

And off topic, this happened a couple hrs down the SC coast from me:
http://www.southcarolinasportsman.com/d ... hp?id=1605
http://www.charlestonfishing.com/forum/ ... _ID=113765

Doesn't that look like an Outback?

The old SS Drive is very durable, but quite sensitive to proper chain tension. Current "V-2" sprockets do not have this problem.

I agree with Stobbo -- the tightening sequence is important.
1. idler cable
2. front chain/cable
3. rear chain cable

Give your cables a squeeze test at mid span. You should get about 1/8" deflection for the idler and front cable and 3/16" at the rear. Cycle the Drive a couple of times and re-check your work. Make sure your Nyloc nuts are not backing out (ie: tension remains stable after use). This should do it, but if not, tighten further if necessary. Looser promotes chain skipping with the old SS sprockets and tighter increases friction. Here is a link for more info. Item #3 illustrates the squeeze test: viewtopic.php?f=60&t=12578

Did Stobbo say anything about sequence? I don't see it but I'll incorporate that part of the advice.

Haven't had time to play with again yet but maybe tomorrow.

Thanks,
John

Nah, I never mentioned sequence - didn't know it was (still not sure if it is) important... just tighten them up until you get the right amount of deflection, then give the pedals a few cycles back & forward to even things up, test deflection again and adjust as required. Cycle through this a few times and you should get a feel for the point at which the cables start to make the drive feel tight/siezed.... then back off a quarter of a turn & try again.

As to question of whether the sprockets are worn ? ...I very much doubt it. My drive has had long & hard use and is perfectly AOK when the cables are at the right tension.

Perhaps I didn't phrase it well. I agree with stobbo with regard to tightening the cables rather than loosening them and including the idler cable. The addition of the sequence is to simplify your job. You can adjust them in any sequence you want, but you'll have to readjust them again after you adjust the idler cable since it affects the others (tighter idler cable puts more tension on the front chain and loosens the rear). You'll also find this information on the Mirage Drive FAQ.

The squeeze test was derived from the 2001 operators manual and I've been using it ever since -- never had a chain skip in my stainless drives. Good luck with yours.