"Worth the effort??" Well, if I wanted an inboard cat I don't think I'd design anything that looks like my tunnel boats - or the Villain. I would design something like the Eliminator offshore cat. So, give the choice of screwing up a perfectly good 3.5 tunnel or designing something that would seem a more suitable hull for an inboard - I'd go with a new hull.
If I had an inboard 3.5 tunnel and an inboard 3.5 cat -how can they be differentiated? Can they be differentiated?
I always thougth tunnels had 4-sided sponsons, whereas the cats have 5 and 6 sided sponsons. Also alot of the cats have a V in the tunnel, while most tunnels have a flat tunnel.