Newbie gray water question

[bwaysteve]

On the pre 70's Airtreams without a gray tank where do the drains for the sinks go? I realize people use totes but how does it exit the drain pipes.
Is it connected to the black tank pipe bypassing the tank? Fittings?

[68 TWind]

On my 68 Trade Wind there is a Y pipe connected to the dump valve on the black tank. Gray water and black water exit the same fitting in the rear. There just is no valve or tank for the gray water, it runs right out. The fitting can be purchased from Inland.