My 1983 Hunter 31 has a blue Gelcoat stripe on it. While I was working on the deck, I did a test section of the stripe to see how it would look. As you can see in the photo it was really faded.
Used a heat gun and plastic razor scraper to remove the white and gray vinyl overstripe.
Used Turtlewax bumper sticker remover to remove the adhesive (after trying several other solvents that did not work well)
Wet sanded with 600 and then 1000 grit, and then buffed with 3M compound and Presta polish

Doing this leaning over the edge of the boat in the water did not get me a consistent result (too hard to reach and see up under the rail) however the results were quite impressive.
Here is what I used
Once we haul her out, I am planning to do the entire hull with this method. Still not sure If I am going to replace the vinyl accent stripe.
Try the sand and buff as explained by Maine Sail. If the results are not what you want, only then would I paint.

Used a heat gun and plastic razor scraper to remove the white and gray vinyl overstripe.

Used Turtlewax bumper sticker remover to remove the adhesive (after trying several other solvents that did not work well)

Wet sanded with 600 and then 1000 grit, and then buffed with 3M compound and Presta polish

Doing this leaning over the edge of the boat in the water did not get me a consistent result (too hard to reach and see up under the rail) however the results were quite impressive.

Here is what I used

Once we haul her out, I am planning to do the entire hull with this method. Still not sure If I am going to replace the vinyl accent stripe.
Try the sand and buff as explained by Maine Sail. If the results are not what you want, only then would I paint.