I would say so! That 4600-4900lbs is what is called "dry wight". Meaning, no fuel, water, & gear. At 6lbs per gal, if you have 20 gals of fuel, that alone is over 100lbs. Now add your anchor and rode, dock lines, fenders, VHF, PFDs & anything "you" put on that boat. I am sure you would hit another 100lbs if not more. I would go with a class 4 hitch, but thats me. I would hate to have my boat break loose from me as I am driving.
Now with that being said, what about the trailer? Again I am guessing, it is most likely in the 600 to 800 range. If we use ALL low numbers, boat 4600, fuel 200, gear 100 & 600 for the trailer. Total 5,500 lbs. As to total "GROSS WIGHT" for the towing SUV/truck, now you must add any thing (even your self) that you put in it. So if your "GTW" & what ever goes into the truck = "GCWR"
Read this link:
http://auto.howstuffworks.com/auto-part ... weight.htmForgive me, I am NOT tring to be a "wet banket" but you need to know what you are getting into!!