I have been discussing the whole planning hull vs. diplacement hull thing a lot lately. I have paddled both (embudo, gradient, overflow x, micro, CFS, hukka, MAC-1) I paddled a BIg Gun for about 2.5 years and loved it. For reference....check out http://www.kayaking.peak.org/
and look at runs like the upper upper cispus, the Truss, the Little White, Wind river...etc. WE have A LOT of big waterfalls here in the NW. Landing flatt off of a really big waterfall hurst....period. Boofing semi-huge falls and landing flat in a planning hull is usually not a problem either because of the aerated water at the base. Vertebrae have been cracked in just as many rounded hull boats as flat hulls. The Big Gun was semiplanning and now I paddle a MAC-1.....I was a little worried about the flatter hull but now I love it....here are two more boats:
PROS: Volume distribution lends to speed when busting through big holes and stable resurfacing after drops. SPEED, 8' boat that is fast and turns on a dime. Just as at home in low volume steep stuff as it is in the big gnar. Not an autoboofer but very easy to boof. You can really adjust your entry angle off of a drop with this boat...even after throwing a huge boof stroke......good for not landing flat when you want to boof over a manky hole at the base of a drop. Tracks really well, holds a line even in pushy water. Clip-in points are large. Planning hull really smashes the foam pile if you boof over big holes. Bow pierces holes but there is enough up-turn so as not to pin. Surfs really well...good for must make ferries or just for surfing waves on your favorite creek run
Doesn't have the tendency to back ender...like the huck, hukka, micro.
CONS: Cockpit not as easy to get out of as the Big Gun (most aren't) . they had some problems with the hukka plastic but they changed it with the 2005 boats...I think. If you don't install rubber washers on all the bolts, the boat has a tendency to take in some water. The edges are a little ....welll....edgier than the Big Gun but I haven't noticed any reprecussions yet. Seat and thighooks are a little hard to adjust.
This boat would be good for low and high water runs like Bailey, Escalante, crystal gorge, Big South, S. St. vrain, Lake creek, Vijacito (sp?), Oh-be etc...I lived in the front range for 5 years
PROS: Lots of volume to keep you dry in the big stuff. Volume distribution leads to speed after drops/holes. Easy to turn. Sealed bulkhead is cool....great for storage...the new ones stay REALLY dry. Cockpit allows me to get both of my knees out and stand up on the seat while still in the water. Punches holes great. Boofs like a champ.
Cockpit is so HUGE that most skirts implode (even Mt. Surf) without an implosion bar. Sidewalls are VERY high. This boat is a pig as far as speed goes and very unruly in low volume stuff. Hard to change the entry angle off drops mid-air. Gets knocked-off course too easily.
Good for Big water runs through and stuff like Oh-be, Bailey, Big south, Viacito (sp?) and Big water here in the NW, BC, N cali. Basically a great Big Water boat although there are better....see the MAC-1