Sacrificial anode on the hull

Anyone here have one mounted to their boat hull?
I think everyone has one on the motor.
I've heard you got to have one if you run in saltwater.
My boat is freshwater only so far but I may venture into the bay one day.

I don't have one but I should get one since I do fish in saltwater.
I fished in salt for several years and thought everything was good but one year I noticed my transom was rotting. I ripped it out and noticed the aluminum was corroding quite badly in a few areas behind where the wood was.
I don't know if a zinc tab will help for areas like this. No matter how much you wash down it seems like salt gets trapped in areas like this. There is wash down solvents that might be better then anodes. Talk to an old "salty" and see what they say.

I've lived all of my 34 years in and around saltwater. I have used aluminum boats in salt the entire time and have never put one on an aluminum boat. I'm NOT saying don't do it. ANYTHING you can do to preserve your boat is worth it or if it gives you peace of mind. IMO if your going to leave your boat in the water, please add one if not buy a device that is an electrical anti-electrolysis device (expencive but the best prevention for boats staying in the water). I use my boats every weekend in saltwater and I just hose it down and flush the motor after each use. Most severe electrolysis is caused by stray voltage from your electrical system or some power source in or near the water. A battery grounded to a aluminum hull that sits in saltwater will eat aluminum like a ice cream at an 8 year olds birthday party. I always unhook my batteries after each use or turn the battery switch off.

Hope this helps. If you want more info. Google boat electrolysis and there is tons of info. and devices to fight it. I wouldn't fret about it as long as you soak your boat for several minutes. I always wet the entire boat first to disolve all the salt. Then I go back and hose it down. I am having problems with my TM but it is my fault. It is a freshwater TM.