It seems logical that you would loose height inside the tubes, but I always thought one of the benefits of the D series stuff is that you get more width between the tubes that makes up for it. Maybe that is how it is theory but not reality though.
I saw a Holiday trip on the Yampa that had 18 foot Maravia rafts with diminishing tubes and it seemed like they had an extra foot of width between the tubes compared to other 18' boats I've seen. Honestly, I think a 16' version of that is my ideal boat if I was buying new today. At least for now I'm super happy with my 16' Avon Pro...
I saw a Holiday trip on the Yampa that had 18 foot Maravia rafts with diminishing tubes and it seemed like they had an extra foot of width between the tubes compared to other 18' boats I've seen. Honestly, I think a 16' version of that is my ideal boat if I was buying new today. At least for now I'm super happy with my 16' Avon Pro...