Weak spots?

It's so it can't be resold.

Well that makes sense but it could still be used and a great kayak correct.

If it was shipped or requires shipping most companies would rather ship you a new one and not hassle or pay to have the damaged item be shipped back for disposal.  It makes good business and financial sense to save the company money and to have a very positive customer service reputation. 

Company now monitor forums like NWKA which uses or buys their products knowing that in this electronic age of world wide instant communication that bad customer service gets around very very face and they stand to loose out on profit, customer loyalty, and reputation.  Since this fast and far reaching communication era the customers has the advantage. 

Costco monitors each members purchases and would rather take $300 returns with no questions asked when they know the member spends a couple $1000 a year.  That's how Angie's List, Yelp, and e-Bay's feed back scores came into existence.  "Power to the People" and in this case "Power to the Yaker" so "Yak it it up" and keep talking about the "Good, the Bad, and the Ugly.

Sending in the serial number is pretty standard on factor returns.  They don't want it back, they certainly don't want anyone to pay to have it shipped back, but they don't want you selling it either.   It's a bit like tearing the front cover off paperback books when book stores through out books. 

You are now a serious source of plastic for welders out there!
http://www.urethanesupply.com/kcwelder.php

Yep,  standard practice to cut out and send in the serial number. Do whatever you want with the rest.  Including patching it up like Frankenstein and get it wet again.

I should have taken a before and after pic of my patch job. But I am really pleased with how it turned out. I cut out the serial number it was about an inch wide and three inches long.

I cut some wire mesh and melted it into the plastic for support. I then cut up a white bucket with the recycle sign HDPE 2. (High density Polyethelene) I began to heat and melt the plastic together working it into the kayak. When all said and done I sanded it smooth.

I pushed really hard on it. No cracks and it all seemed to move together as if it was now part of the boat. Thanks guys for your posts it has helped a lot!

Nice job on the patchwork! Looks like you have a spare now