mirage fin stretched, use heat gun?

So on my second trip with the kayak I didn't have the drive properly seated for the first ~7 minutes and the rear fin was rubbing against that small ledge at the rear of the slot.

I noticed it was a little difficult to pedal at that point and pulled it up and corrected. The bit that was rubbing had deformed so I had this little 1 inch deformity. I guess over the next few trips that deformity worked its way across the fin and now it seems like the entire backside is stretched out.

Some pictures:
These two are showing the rear fin when I've properly seated them, meaning I've shoved it as high up as it goes on the rod. The stretched area bows out when I do this, and I assume it doesn't stay like this for long in use.
http://dl.dropbox.com/u/29498734/compressed.JPG
http://dl.dropbox.com/u/29498734/compressed2.JPG

Here's what likely happens during use. The front side of the fin slides downward slightly and the tab at the top of the fin slips out. So the fin is able to really billow out when you're pedaling.
http://dl.dropbox.com/u/29498734/extended_tab_out.jpg
http://dl.dropbox.com/u/29498734/bad_fin_extended.JPG

And for reference, here's the front fin and how it looks all the time:
http://dl.dropbox.com/u/29498734/good_fin.JPG

So I always intended to get a set of turbo fins and I'm wondering if this is the time to do it, or can I salvage this fin with a heat gun?

It seems like if I can shrink out the stretched area, then it might assume its proper shape where that tab at the top isn't hanging outside of the slot.

Sorry, I don't think you can shrink that with heat.

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Hobie Island Sailing since 2006

I should also ask if I'm going to cause more harm to everything if I keep using it like it is. Performance-wise I don't notice a difference really.

The plastic rotating attachment piece at the end of the fin (with the pin) seems to rotate a little more with the fin billowing so much each stroke. But that's about it.

It probably won't affect the performance hugely.

If you were planning to get Turbo fins, now is always a good time to go & get them - unlikely you will be disappointed.

I only use turbos and have loads of spare fins - if you want one, let me know & I will post it to ya. Just pm me. NB I live in NZ so you will have to turn it the other way up when it arrives

This could be my imagination, but it looks like your rear mast may be bent back slightly. You can check this out by comparing the distance between masts at the bases vs. at the tips when centered. This can cause similar symptoms. Another way to check is to swap the fins front to rear and see how they sit.

Yes I am with you on this one Roadrunner, the rear mast looks bent.

Yep, that's the problem. The small deformity from me pedaling out of allignment is still there on the fin, but after taking them off, I can see both fins are exactly the same shape.

The rear mast is slightly bent, I must have whacked it on something. It seems odd for the rear one to be bent instead of the front, but that's what I'm dealing with.

Nice catch, Roadrunner. It should have occurred to me to take them off and compare, I'm a dope.

Now to figure out how to unbend it.

Followed this thread in the faq: viewtopic.php?f=60&t=13439

Everything's back in alignment, thanks for the replies everyone.