The tube on the Venus Probe is 14 1/2 inches long.

I was actually more concern about the inside and outside diameter of the thick walled tubes being the same.

The one on the Venus Probe is just big enough for an Estes 18mm motor to fit inside.
The outside Diameter is 19.40 mm. It's a pretty rigid tube as far as model rocket tubes are built these days. They sure don't make then like they used to.

I'm not sure about the Skywinder.