All may not be lost on your outback, I've had quite a few Hobie's and used the heck out of all of them. Someone with a Getaway was asking how to clean up his hull bottom, this is the thread ( viewtopic.php?f=23&t=45650
The Outback hulls are very thick and can be scraped (as outlined below) many times before fearing wearing through the hull (they are suprisingly durable). I have also witnessed the local Hobie dealer (Economy Tackle in Sarasota,FL) fixing up dinged and scratched hulls with a hot wire feed iron (in the hobie catalog), that gives amazing results on big cuts and scratches. You might inquire with the local dealer about cleaning up your hull before throwing it out, or do the bulk of the scraping and cleanup yourself, then optionally having the dealer only repair just the deepest scratches. I can't imagine it costing more than a couple hundred buck to have done, or nothing if you do it all yourself.
basically this was my response:
The hulls are very thick on the bottom, and you can easily scrape the scratches off probably several hundred times before starting to worry about scraping through the hull. Typically if you leave the really deep scratches alone, and fix all the shallow scratches, the hull will look pretty good when done.
To scrape the hull you take a single edge razer held vertically and just swipe it back and forth, it peels the outermost layer off yet leaves a nice shiny and even finish (once you get the hang of it. I used to own and operate a rapid prototyping and engineering house, and this was how we would finish the plastic models made from our SLA and SLS machines.
Though I have never tried it on a Getaway, if your really handy you might be able to use an electric heat gun (looks like a hair dryer) and carefully wave over the surface to shine it back up after scraping. I don't recommend using a blow torch (just too risky), and you must scrape first or you will trap the dirt in the plastic. Regardless of what type of heat you use, you have to be very careful as to not overheat the hull, do small areas and move around a lot, I use a water hose to cool the areas down (so do it outside).
Usually the scraping is all that is needed to make the hull bottom look good, the electric heat gun is probably overkill on the hull bottom.
I have also put on a very thin coat of Krylon clear plastic spray paint after scraping with pretty good results (it bonds to the plastic chemically). After 24 hrs it's un-removable and looks nice (an easy way to get a nice shiny finish). Like I said I have not tried any of this on a Getaway hull but all this works nicely on most standard kayaks (most brands).
Hope this helps you