When wet sanding your boat, Can one put to much Dawn in the water bottle??? Thanks

Yes.  Anything that can be done, can be overdone.  

 

Basically, the soap in the water acts as a surfactant.  It's purpose is the break the surface tension of the water, and make it "thinner".  That way, it more easily breaks up the gunk that comes off as you sand, and prevents that gunk from clogging up the sandpaper, making the sandpaper more effective and last longer.  That gunk will also cause scratches in your finish.  It's kind of the same idea as using a light oil.  You're not trying to reduce friction on the surface, so much as trying to float off particles to increase the overall friction.  

 

It's often called a "lubricant" in this context, but that's not really a good term.  You don't want a real lubricant while sanding, as that will reduce the effectiveness of the sandpaper.  Imagine covering sandpaper in lithium grease and trying to sand.  It won't work well.  It'll sit between the sandpaper and your work and won't really let the two surfaces interact.  If anything, you're trying to lubricate the gunk you've already sanded off to fall away, not lubricate the sandpaper and surface you're working.  

 

If you use too much soap, the soap becomes the bad kind of lubricant and the sandpaper doesn't do as good of a job.  Though, I'd think you'd need a lot of soap to make the water thick enough to cause this problem though.  Straight soap would do it.  But you've got a fair amount of leeway to play with here.  Still, it doesn't take too much soap to break the surface tension of water.  And since even straight water should work pretty well, it would probably be better to err on the side of too little soap than too much.  If you're having problems with the sandpaper clogging and scratches, try using more water as you sand.  Sometimes, especially with really fine grits, you have to keep it flooded, and still be prepared to switch out sandpaper sheets often.  

 

Now, having said that, let me say that I've never actually sanded a boat.  I've wet sanded a ton of things in my life though, mainly wood, metal, and occasionally plastic.  Never fiberglass.  So I won't claim to be the authority here or have direct experience with what you're doing.  I'm just passing on what I've learned.  I had a college professor tell me once that sanding was good for your soul (a sculpture teacher, one of my degrees is in art).  He was crazy, for sure.  But he had the right idea.  When you get to the sanding stage, especially if you're trying to get a super smooth finish, you really have to prepare yourself to take it slow, be methodical, and not try to rush it.  Know it's going to take forever, and be okay with it.  Treat it like meditation; a chance to clear your mind.  Trying to rush it will always lead to a subpar job.  Just accept that it will be long, hard work, and find a way to enjoy the work.