I just purchased a 87 century resorter and i have marks from years of abuse from bumpers on the hull of this boat. I have read several forums talking about rubbing compound or muriatic acid wash, but not sure what products or method is the best. I do not want to hurt the gel coat on this boat. Any advise would be great these marks are all over the boat

Don't use muratic acid. Try 3M Wax Restorer as it has a wax and rubbing compound combined. It that doesn't work, just use a good rubbing compound.

23 years of use may be time for new paint I actually have a neighbor who painted his old 20+ yar old boat got it done for like 2K, yea it wasn't the greatest but looked much better than before.

Muratic acid is only for removing hull staining on the bottom of the hull.
Use some 3M rubbing compound and good quality buffer. Which compund depends on how bad and how deep the scratches are.

Try a "clay bar" you can get them just about anywhere...Autozone, WalMart, etc. If that doesn't work you might try the "Magic Eraser", you can find it anywhere like a grocery store, I think it's made by the Mr. Clean company...works great. Both of these are completely non-abrasive. Rubbing compounds are a last resort.

+1 on the Magic Erasers they work great for this kind of thing.

I would not use Majic eraser on the gel,it will scratch the gel. Then you have to deal with that

I am sure I will be scolded for posting this. I have used lacquer thinner to easily wipe off marks like that.

I think you must be thinking of another product...Magic Eraser's are about as abrasive as a sponge...in essence, that's really all they are with a very non-abrasive cleaner built into them...they slowly deteriorate as you use them...but it's amazing what they're capable of cleaning.

I've tried the Magic Eraser on gel- it will scratch it... or at least it did mine. With somthing new I always try it where it won't be seen and a small area, so no big deal. Try it in a hidden location first to see for yourself. It works great on just about everything else, though!