Installation of a Hepvo valve replacing the P-trap is a common Casita mod but rarely seen in a Scamp. I was intrigued by the opportunity to save some space under the sink so I ordered one.
The biggest trick was going to be adapting from the 1 1/2" drain in the sink to the much smaller tube that Scamp uses for the sink drain. Unfortunately, I had to start by adapting the "1 1/2 p-trap line" which isn't actually 1 1/2" to a standard size. Ended up picking pieces from three different locations in my local big-box store to come up with the cleanest adapter.
It actually looks pretty good once it's in place, and saves several vertical inches of space below the sink. I added a custom bracket after this picture to add some support to the back end. I didn't have to make any changes to the original drain line other than shorten it.
Time to hit the road for a few days and test the mod.