Mr Jack, Dont know if this will help, but here is what I did. Thanks to Pop at the Mom & Pop Hardware store.
I got one of these and it adapts the plastic drain to a PVC coupler to a male hose fitting.
There are more pictures on page 11 of my Build pic Linky.
The hardest part to find was going from the plastic to PVC. This adapter did it. You might then beable to find a coupler to attach to the adapter then to your barbed tube fitting.
Mk