Hi Peggy,I ordered your book , great info and easy to read.any way I am looking at a diferent steering setup for my catalina 250.and I need a little more room than the factory holding tank is giveing.I would like to put a larger one in there too , I leared to fush fresh water when where done with the boat. I think the tank is 9 gallons . So I need a lower tank but if it was a L shape,there is more room . Is there a custom tank maker somewhere ? Also I measured some gas tanks that might fit ? they have a 1 1/2 fill , a vent . all I would have to add is a 1 1/2 discharge line.Thanks