I know we are all frustrated at the smallish Holding tank on our C36 (only about 17 gallons on my '99 C36 with tradional setee). Its not that big of a deal for me (typically only a weekender sailor with 2 adults, & maybe 2 kids). But I know for all you people that are in areas where its hard to get a pumpout or you have more than a few people on your boat, its woefully inadequate So I am at my boat now and I was taking a look at the tank situation. It is a Ronco brand Tank model # B123 (obviously custom made for Catalina)...Go to link below (http://www.ronco-plastics.com/) and do a tank search for 17 Gallon tanks. It is tank # 1 and pops right up at their site. Well I noticed on my boat there is a considerable area that is not being used on the boat, it is the centerline of the tank under the port settee bench. It is about 4.5"x30"x8" for about 1080 cubic inches which is just over 4 1/2 Gallons !!!. If Ronco/Catalina just modified this holding tank to add this 4.5x8x30 inch rectangle to the top inboard side (the side that already has 13 1/2 ") then you will get about 4 1/2 more gallons. A 25% increase AND THIS IS WITH NO MODIFICATIONS TO THE EXISTING BOAT, PLUMBING or STRUCTURE....How cool is that !?! Next, as I suggested before, if you just cut an access hole between the dividers under the port salon settee then you will be able to extend the forward part of the Ronco B123 Holding Tank another 17 inches (Approx 17"x15"x7" but its an odd shape just like the original holding tank). This forward extension would not need to be as deep as the main existing tank, but this extension should get you almost 8 more gallons. Not only that, this would shorten the run from the head to the Holding tank by 17" (BTW the run from the head to the tank is already fairly short at only about 3 1/2 feet and its mostly straight and downhill as it is. This is one area of design that Catalina did right !!) But now the run will be only about 20" and Like Peggy Hall say's " The further the tank is from the head, the longer ANY toilet has to be flushed to move the bowl contents from the head to the tank. "....so this allows even less water to be used...
With the space that is readily available on this boat & with these 2 modifications you can almost double your Holding tank capacity from 17 Gallons to almost 30 Gallons ! ok....so who's the first one to approach Ronco and have this done...;-) (BTW Peggy do you know if its possible to take an existing tank in good shape and have Ronco or anyone else modify it ?!?)
With the space that is readily available on this boat & with these 2 modifications you can almost double your Holding tank capacity from 17 Gallons to almost 30 Gallons ! ok....so who's the first one to approach Ronco and have this done...;-) (BTW Peggy do you know if its possible to take an existing tank in good shape and have Ronco or anyone else modify it ?!?)