OL Sarge:
Actually it's really easy to add your boat name to your kayak,
This is the boat name on my TI

It is really easy to do and the letters stay on really well if prepared properly.
My wife has Silhouette Cameo die cutting machine she uses for scrap booking and stuff (kind of like a Cricket die cutter only better).
We went to a local crafts store and bought self adhesive vinyl (it come in small rolls in the same department at Michaels as where they have the cutting machines). We just used standard black nothing special (ie nothing like super duty marine grade for 50 times the price, just normal grade).
It took her all of 2-3 minutes to program it and cut out the letters and artwork. While still framed in the backing it's best to just tape over the whole works with 3M painters tape, this keeps everything aligned properly when applying.
Surface prep is everything when doing something like this.
First clean off the area scrubbing very well with de-natured alcohol.
Next wipe down with Heptane solvent (be careful heptane melts polyethylene) You can get heptane at Home depot in the paint department it's called Bestine solvent and thinner in a white and red can, you can also order it here (
http://www.amazon.com/gp/product/B000HF ... F1X4P8H3FJ).
If you rub it around a little while it prepares the surface for bonding (softens the polyethylene). Now after wiping off the excess you spray on Krylon clear coat (the kind specifically that is for plastic (guess what the active ingredient is " Heptane") just spray the area around where the letters will go (doesn't need to be neat because its clear). Let the clear dry a little while (maybe 15 minutes max), then place your letters. Make sure they are pressed tightly and rubbed in as much as possible. Once in place and rubbed now spray another coat of Krylon plastic clear coat over the whole works, a nice wet coat making sure is soaks the edges around each letter (this is the main bond that holds the letters down like a zipper). The letters will never come off under normal use unless you rub a dock or something. The clear coat has UV inhibitors so that helps if the vinyl is not UV protected outdoor type (which is way more expensive, and not necessary).
Black is the very best color to use for your letters and artwork because the colorant they use to make the black color is called carbon black (it's a colorant additive), carbon black blocks all UV light and is the very best color to choose for anything made out of plastic that you might want to leave out in the sun. Of course you can buy special UV inhibited outdoor plastics for 50 times the price it's your choice. Any other color won't last out in the sun (even if it has uv inhibitors typically) The UV invisible light unbinds the chains that hold the plastic together inside under the surface very quickly on any plastic.
Hope this helps you
Bob