Hobie Cat Forums

New Hobie TI. (Built end of 2011, took delivery this Spring) Third time on water. Rear Mirage drive - brass knurled nut works itself through the fin (no visible tear in fin). Almost lost fin. Have to remove the ring and remount, but it pulls through again. Can fix by adding a washer, but this should not be happening with minimal time on the boat. Anyone else having such a problem? Love the boat otherwise.

Sounds like you had the drive in crooked - read this post to understand the issue

viewtopic.php?f=60&t=12836

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Jacques Bernier
http://www.hobiecat.com/
http://www.facebook.com/HobieCatCompany

Read these forums and the manual before going out. Have been very careful to put the drives in correctly, bought storage bags. Have not installed drive seals. Will continue to be careful with installation of drives (do not believe they were inserted at an angle), but the issue is that the fin will no longer stay on. The brass knurled nut pulls through the rubber fin. What is now the suggested remedy? This has happened twice during the same day out (noticed when pulling drive up and out of well prior to shallow water)

Get a new fin from your dealer
You don't need to take the drives in and out just to get through shallow water, just push 1 foot forward and 1 foot back - that will put the fins up against the hull and you'll be able to get through even the shallowest of areas - as well as beaching...I always leave the Mirage in place.

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Jacques Bernier
http://www.hobiecat.com/
http://www.facebook.com/HobieCatCompany

Do you mean that the knurled trailing-edge-of-fin-tension adjustment knob falls off the fin-tension adjustment screw?

If so: are you sure it was screwed in sufficiently in the first place? (not insulting anyone's intelligence - just starting from the bottom up)... it is sometimes tricky to ensure that the knurled knob is engaging with the screw threads as you turn it! Assuming that the knob is properly seated and that you have tightened it up onto the adjustment screw OK it is still possible for the knob to gradually unscrew as you pedal - this happens on one of my two drives: dunno what causes it on one rather than the other but there you go (I suspect that the constant twisting of the fin bearing on the knob gradually works the knob off the threads and that the knob is a bit slacker on the threads on that particular drive rather than the other). The solution is a drop of non-permanent loctite on the threads.

If not: perhaps you could post a picture?

You are absolutely correct that if the adjustment knob does come loose, your fin will slip off the fin mast and be lost for ever in Davy Joneses Locker: I have had this happen to me when the trailing edge of the fin actually wore through due to extended use, fell off the screw & knob assembly and down it went...

The moral of the tale is ANY time you pedal and find no resistance, whip the drive straight out and examine it to see what the fault is.

Thanks. The fin is not damaged so I hate to replace it - would like to repair the situation. The brass knurled nut cannot totally work its way off the threads, so I will look at tightening it/non-permanent loctite and possibly putting a small washer with it if necessary to prevent it from working through the fin. Guess I will order a spare fin to have on hand if the problem continues. Looks like a spare parts box is in order for my new acquisition.
My dealer is not well versed on this particular boat, so I cannot attest to the "setup" on the drives. Had to rework the sail stays.
Already ordered the materials to add the second bungee on the AMAS - saw the need for that on the first sail. Great step by step photos on the forum - thanks!
Fresh water lake, brush around the shore. Been taking the drives out as an additional precaution when coming into shallow water, but sounds like that is not necessary. Just remember hitting a stump with an outdrive 20 something years ago (big ouch).

my advice FWIW: always take the drives out when coming in to shore. There are people who do not but why tempt fate. Treat your drive well and it will treat you well.

The first 3 years with my AI I always folded my fins to the hull. I replaced a fin about once a year. I now remove the drive near shore, and I haven't replaced a fin since (4+ years). Good advice.

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http://KayakingBob.com - - - - - - - - - - - - - - - - - - - - - - - - - - - 2007, 2009 & 2010 Hobie AIs and a 2010 TI

Thanks Stobbo. Thank was my original thought. Going with your "gut" usually proves right!