what are the down side to 1860 hulls

I don't really see any other than not being able to fit into tight spaces or tight channels as easily as a 48" wide etc... I always heard the narrow the boat the more maneuverability in narrow areas, the length doesn't come into play that much.

I don't see any downsides to my 1860 hull I've had it in tight spots and sticky situations.

I have a 1660 and wish I had a 1860

As said, you need alittle more room to navigate tight areas, but in the up side, they draft alot less water, so you can get going in shallow situation easier. You can get in some pretty tight areas with a little experience running one. We took my 2060 dual rig with a full hard blind on it down to TN and ran timber over new years. It was tight, stumpy and alot of really tight turns between trees. We went through everything the narrow boats did, you just need to know what your minimum width is to be sure you can make it. The 60 wides handle load really well, four-five men with a stock 36 is no issue.

PW