Replacing aluminum holding tanks is common...
Urine eats through 'em in just a few years. But it's rare for an aluminum water tank to fail in less than 20 years. Why do you think you need to replace your water tank?Ronco Plastics is your best source for plastic tanks...they make TOP quality, thick-walled roto-molded tanks, and have more than 400 shapes and sizes--over 100 of which arenon-rectangular--to choose from..and for a VERY reasonable price. I'd bet they have one that will fit your space. And you can spec your own fittings sizes and locations, to be installed by them when the tank is made. Their catalog is on their website at:http://www.ronco-plastics.comAs for getting the old tank out...that depends on where it is. It' more of a challenge on some boats than it is on others. Enough owners have done it that you should get lots of replies to that one.And before you start this project, I strongly recommend you read the articles in the Head Mistress forum Reference Library.