I have a 1961 26' overlander and want to know the size of the black water tank if anyone would be so kind to let me know, also the gray water drains come out below and into the Black Tank drain pipe, am I missing something or does the gray water just drain to the ground. What does one do when he has no gray water tank at a camp with no hook ups?
I am fairly certain that your Overlander has an eight to nine gallon black water tank - - one of my friends has a '60 Overlander and I have a '64 Overlander and both of our Overlanders have black tanks that are slightly more than 8 gallons but less than 9.
Unless I am mistaken, your '61 Overlander still has the black tank that is mounted on top of the floor (the toilet is on a raised platform above the tank creating a step-up to the toilet). If this is the case, your only option with the gray water is a blue porta tank for gray water (these are available at most camping supply outlets in a variety of sizes - - I have a 10 gallon and a 20 gallon and find the 10 gallon to be a bit more practical). If the black tank on your Overlander is mounted below the floor as is the case with my '64 Overlander, you have the option of "backing-up" the gray water into the black water tank. This is done by placing a solid terminator valve cap on the dump tube and then opening the dump valve on the black tank - - the gray water then will flow into the black tank (downside is that the black tank will fill VERY quickly and dumping becomes a bit messy as the dump valve must be closed prior to dumping and the area between the dump valve and terminator cap will be filled with sewage that will spill out when the terminator cap is removed - - you will need a small bucket to catch the trapped sewage when dumping).
If your Overlander has the above floor black tank, you do have the option of adding a gray water tank below the floor. It would be somewhat more costly than using a blue tank, but would be a more permanent solution. I haven't investigated this as my black tank is under the floor which severely limits the viability of adding a gray water tank.