Since our existing tank was from Ronco, my initial investigation was targeted at the current collection of tanks available from Ronco. As it turned out earlier Catalina’s did have a holding tank that was larger, considerably larger. I requested info from Catalina about getting a larger holding tank and they recommended the 30 gallon tank from Ronco (number 60170 or Ronco-B179 http://www.ronco-plastics.com/newRonco/product_details.php?prodID=72) versus the Ronco-B212 (http://www.ronco-plastics.com/newRonco/product_details.php?prodID=104) that we currently had. Apparently the C34 MK I’s are supposed to be outfitted with the larger tank (or so I was told). I did some preliminary measuring and noted that my thru-hull for the macerator would be in the way, plus the deeper dimension on the port most side of the tank could be a bit tight.
The attached image shows the existing B212 tank and the thru-hull location. The new B179 would be almost as big as the storage locker’s opening, thus covering the thru-hull.
After looking through their catalogue of tanks I decided that the B179 was a pretty good fit, but the dimensions in the boat against the hull are so fluid, that it was hard to tell if it would fit. The fit seemed close. I took down the dimensions of the B179 and proceeded to build a life size model of the tank out of cardboard over a couple of evenings. Then on the weekend, took it to the boat and crossed my fingers. The fit was close, but in the wrong direction. It was too big!! Had the settee locker been either wider or deeper it might have fit. I was around this time that I also noticed a slight difference in the Catalina 34 layout. Earlier vessels had a port settee that had a straight edge along the aisle. On our 2002 Mk II version, the port settee was curved in towards port by about an inch and a bit. Our aisle is slightly curved. As a result the locker was narrower.
I had looked at other manufacturers, but the Ronco catalogue did provided the most variety for our potential situation, but none of the others were as close as the B179 or B212 (our existing one). It was time to go custom. So this time I used the cardboard to build a tank in place. I constructed a cardboard model of a tank that would fit with 2” clearance forward and 3” clearance at the aft end. My hope was that this would allow for enough room to have the 1½”right angle input at the top of the tank. Unfortunately I was instructed that I would need a minimum of 5″ clearance at the top, so I decided on a side inlet and increased the height by another 1½”. I estimated that would end up with a tank with almost 25½ US gallons. That was acceptable to us.
Here is a series of images that show the comparison between the Ronco-B179, Ronco-B212 and the custom tank.
So now that we decided to go with our custom tank, we just needed to find someone to build in.