Re: best way to clean hull?
With all the boats I have and the terrible water I use them in, I've learned the easy and cheap way to do this long ago...
I use a simple muriatic acid and water mix. Either buy the gallons at Lowes, or just buy 'The Works' toilet bowl cleaner from Walmart (Lowes and HD sell it to I believe), it's all of about $1.40 a quart. Avoid muriatic acid from HD because it's 14%, designed for swimming pools. The Lowes or 'Works is 20%. HD will work, you just have to add less water..
Get a cheap $9 garden sprayer from HD- Make a mix of 3 parts water to 1 part acid. Pour it in the sprayer.
An "on" water hose with a shut-off nozzle for frequent rinsing...
Here's the fun part. Pump the sprayer, and spray on, about a 1 sq. foot area at a time. Where there's water spots (aka calcium deposits) the acid will smoke. The acid works great, but calcium will quickly neutralize the acid, like in 5 seconds. So spray, wait 5 or so seconds, and repeat until the smoke stops... RINSE WELL with the water hose, including the trailer, then move on to the next sq. foot...
It takes me about 45 minutes to clean my 26' Chap, and I typically use less than 2 quarts of 'The Works". I never use a brush, just the sprayer. Works great on the outdrive too..
FAIR WARNING, as cheap and easy always has its caveats! --DO NOT GET THIS STUFF ANYWHERE NEAR STAINLESS STEEL. It will darken it. It may affect some aluminum, but it has NO effect at all on pontoon logs, other than removing the calcium. Your trailer will be fine as long as you keep rinsing... same for your driveway. It won't hurt your lawn either. Rinse the sprayer out with water afterwards, and it'll be good for 5 or 6 uses (the trigger spring is the weak link with the acid)