My old boat was painted with automotive paint/clear. I could wash the scum line off with car wash soap and a brush.

Now, with a white fiberglass hull, the scum line from a weekend in the water is a little tougher to remove. I searched OSO and found most had good things to say about Power 1. My only concern is the painted surfaces of the drives and tabs, especially since I stripped and repainted them myself last year. We all know you can never duplicate Merc's paint job and I'm cautious with those things. I read some wipe Power 1 on the dry surface and hose off, and also some were using a spray bottle and hosing off. Anyone use this stuff and had any problems?
Any other products?

Zep toilet bowl cleaner

wipe it on let it sit a couple minutes rinse it off

https://www.booyahclean.com/collecti...t-hull-cleaner

Power 1 works great just watch your trailer if its bare aluminum, it will discolor. Have 3-4 gallons on hand all the time.

I use sno bol, nothing sadder than the scum…… this was only from 5 days sitting in spring lake which is connected to the grand river.

I bought some of this since it's non acidic and my new black hull boat didn't like On/Off. Haven't tried it yet but hoping for good results

I have used it for years with no problems. Use a garden sprayer to spray it on and hose it off.

Use any acidic tiolet bowl cleaner and or Muratic Acid. I use a 50/50 mix. Put about a quart of each into a cheap pump garden sprayer. Spray it on, wait 30 seconds and hose it off VERY well. It will not do anything to painted surfaces. It will turn the black plastic cable covers grayish over time. Also will discolor bare metal and it looks like you have an aluminum trailer. Wet down the trailer before applying the acid mix and rinse off asap. I have heard good things about the Booyah, but have never tried it.

Thanks for the replies. I'm wanting to stay away from acids per a friends advice. Power 1 say's it's non-acidic, so I just ordered a gallon. I'll report back with results.

Check out the streaks from the rain. Maybe I should get a storage tank and collect rainwater from my house gutter system. Problem solved and it's free. lol Acid rain? I wonder if it's runoff from the waterproofing treatment on the cockpit cover.
Anyway, I used the Power One hull cleaner yesterday and it worked amazingly well. I poured it into a Zep handheld sprayer and did the each side and the transom separately. Sprayed it on, waited 30 - 40 seconds, then rinsed off with garden hose. My stain wasn't as bad as SwellCraftman's pic above and I only used about 16 -20oz. I poured the leftover back into the gallon jug for later use. I didn't take any after pics, I'm in a hurry to get it ready for this weekend. But, it's clean!
I got it on Amazon prime. https://www.power1one.com/Fountain_o...wer_One_1.html