Pre-fill water in blackwater tank?
I've had my trailer about a year and am really enjoying it. (It's an 18' 1989 Terry TT) I bought used and have been making sure I am learning all I should. I was wondering if it a good idea to fi...
Forum Discussion
Old-Biscuit wrote:Wishbone51 wrote:
Also depends how long your sewer pipe is. How long does a 3" pipe have to be to hold a gallon? For those who say they put a gallon or two in, how much is in the pipe and not in the tank?
1 gallon equals 231 cubic inches
pipe X Pi X length
3 X 3.14 X 24.5=230.79
If drain valve is 24.5" from tank outlet it would take 1 gallon to fill line
But remember-------tank drain is typically in the side of tank so a lip exists which holds some water back from going into drain pipe AND pipe is not going to be FULL until level in tank is above top of drain line.
So couple of gallons into tank will slosh around during travel AND will keep tank bottom wet so that any poop (remember that lip) doesn't dry out and stick/build up etc.
Length X diameter X PI is the radius of the circle. The area is half of the diameter, squared, X length X PI. So, the formula would be
1.5 * 1.5 * 32.7 * 3.14 = 231ish cubic inches.
That means the 3 inch pipe would have to be a little under 32.7 inches long to hold a gallon.
