Dip Tube - Black water tank

[5teve]

Ok so you are gonna get a few randomw questions from me.

The black water tank was retro fitted by me into our boat about 5 years ago. I bought an off the shelf tank and the company did a pretty poor job of the dip tubes being about 75mm off the bottom of the tank.. leaving plenty of waste in there.

I made up some new ones using black poly fittings (common in Aus) however the dip tube keeps falling from the screw fitting as it has to be glued in - is Polyprop and even the best epoxy wont work.

Ive started looking for a PVC based fitting, essentially a reducing bush - but with the ability of having pipe glued in either side, or screwed in one side glued the other or with a through thread. External thread has to be 2" bsp (the tank has a number of these female thread bosses on the top) and the internal thread can be 1.5" or 1 1/4" or plain so I can glue straight through it.

I have been searching for a while - but cannot find anything... has anyone one found a fitting such as this that isnt custom made?

Steve