and a drainpipe end portion having a shape and size adapted to engage threadably an end of a corrugated drainpipe a helically shaped thread along the drainpipe end portion are sized and shaped complementary to conform to the corrugations of the corrugated drainpipe enables threaded engagement of the corrugated drainpipe application_number US 85592486 A description referring now to the drawings and more particularly to fig1 thereof there is shown a recreational vehicle discharge pipe adapter 10 which is constructed in accordance with the present invention and which is shown assembled in place on a recreational vehicle 13 coupling the end of a flexible drain pipe 11 to a discharge pipe 12 of the vehicle to interconnect them in fluid communication the discharge pipe 12 provides an outlet from recreational vehicle 13 for waste removal purposes and thus waste flows from the recreational vehicle 13 through the discharge pipe 12 the adapter 10 and the drainpipe 11 to a remotely located disposal site not shown by interconnecting the drainpipe 11 and the discharge pipe 12 end to end with the adapter 10 a flow path is thereby extended from the discharge pipe 12 to an inlet not shown of the remotely located.