The 420x tube diameter is 11 1/2". That's 2 inches more than the 385 Fast Track. You'll probably find that the Explorer kayaks are better in waves because they are deisgned to be better in whitewater that the Fast Tracks, which are designed to be better flat water kayaks.
Definitely! The seats are very comfortable but pricey for a third seat. We opted for a cheap coleman stadium seat and just used some carabiners to secure it to the boat. Worked great for Grandma or kids riding along.
Thank you for your interest in Sea Eagle Boats. Yes, the 420x Pro Carbon package includes all of the following: 420x Explorer Hull, Two AB50 Carbon Fiberglass Shaft Paddles with Fiberglass Reinforced Nylon Resin Blades, Two Tall Back Seats, Kayak Carry Bag, Auto Dual Action Pump, Two Kayak Stow Bags (bow and aft), Slide in Skeg and Repair Kit. You may also like to know that by purchasing from 'ehome' on Amazon, an authorized Amazon Sea Eagle dealer since 2013, the famous Sea Eagle 3-year warranty is also valid (Our authorized dealer status can be confirmed on Sea Eagle’s website. Scroll to bottom of Sea Eagle’s main web page, click ‘Dealers’, click ‘FL’ and you will see our parent company EverythingHOME listed – known as ehome on Amazon.) If Amazon does not currently have us rotated as the seller featured in the main “Buy Box” offer at the top-right of this listing page, to ensure you purchase from Amazon seller, ‘ehome’, please scroll down to find us among other sellers listed below the main featured offer for the 420x Pro Carbon package and add to your cart under our name. Thank you again and we hope we can help!