How do I protect my white fiberglass boat from dirty stain water?  Every year I clean it to take the stains off but it comes back everytime in dirty water.  Is there a way to prevent that from happening everytime?

To prevent it you’d have to keep it in your garage.  If you get some Bow to Stern, clean the boat well, put on a light coat, let it dry then wipe it off, put on a second coat, repeat, then put on a third coat you will be able to easily clean it when it gets dirty.
 

I have it all over my boat and motor.  All I do for cleaning is run a wet rag over it and dry it off.

I clean the boat every outing so it doesn't matter.  Brown water gets inside the gel coat staining it.  I can use toilet bowl cleaner and spray on it and the stains will eventually go away.  Once in the stain water it turns brown again.  But in clear water its ok.  Thinking of buffing it out will fix this or a chemical solution I can put over it.  Btw it is garage kept I will try the Bow to stern stuff too. 

Bow to stern is a polymer sealant.  It seals the pores in the gel coat, but it takes 3 coats to do it.  Then every few months a fresh coat on a clean boat. 

2 hours ago, Jig Man said:

Bow to stern is a polymer sealant.  It seals the pores in the gel coat, but it takes 3 coats to do it.  Then every few months a fresh coat on a clean boat. 

Thanks.