Introductrion - and newbie here looking for some advice

Been in PDX since 2003, lots of bank  fishing and some boat fishing (bass, coho, steelhead, chinook, etc.), here, been fishing forever.  Lived in AK for several years - that place  will spoil you when it comes to everything  aquatic.  I purchased a used Jackson Coosa kayak a couple of weeks ago and am looking forward to hitting the water soon.  Not an  urgent issue, but I need to replace one shock cord fitting, which was apparently riveted with a plastic sleeve that spreads out into three wings as it gets tightened.  The rivet is out, but there is a cap in place that I'll need to remove to get it to fall through the hull so I can remove it.  The issue is the cap spins both directions when drilling, and that particular sleeve is in a place I can't access.  Any suggestions or experience with this issue?  I'm not sure what  type rivet was used, what's left is a cap with a hole in the center, with 3 equally spaced small slits around the hole itself.
Regards
R Thompson - Troutdale OR   

Can you grind the cap off with a Dremel tool? That way it won't spin.

Welcome. You've found the spot for info. I grew up in Kenai, currently in Anchorage bee have to drive a ways, but the fishing has been pretty good!!!

Sounds like a dremel tool might work - thanks for the idea, I'll check it out.

Welcome!

I had a Coosa for awhile and took it up and down the Sandy a fair bit. If it's near the middle of the boat, you pretty much have to crawl inside it to reach anything. Do you know any midgets willing to help you out? (I have children that loved it - freaked out the mom though.)

If you can't quite get it, you're more than welcome to send me a PM. I live close-ish to Troutdale and would be willing to give you a hand. (Or even rent out my midgets.)

I know my Coosa used the Klamptite rivets (on the right):

I think I'm dealing with the clamp rivet (thanks for the photo - very helpful) at this particular spot, although my boat uses a couple of different kinds of rivets.  I'll try grinding the head off with a dremel tool and see if that works first.  If not, I'll shoot you a PM for some possible assistance.  Thanks for the quick replies guys - great site and glad to be part of it.
Regards