About 5800# makes me nervous. Is that the advertised DRY weight of the boat or the weight fully loaded with gear, fuel and trailer? There is a huge difference between the two. By the time you add mandatory safety gear, 50-200 gallons of gas at 6# per gallon, a trailer and personal junk, you can quickly add another 2000#. You have two problems to consider. The first is the trucks ability to haul the load over highways. The other is the ability to get the boat OUT OF THE WATER at the end of the day. We had boats for about 20 years. I have seen just about every horror story possible at a boat ramp including the ugly smell of burned out trannies in a small pickup or van trying to haul a big boat up a slippery ramp. Boat ramps can run the gamut from excellent to horrible. The worst kind are the ones where the ramp itself extends into the water only 10-15' and then drops off several feet. If your trailer wheels drop off and the water is low and you need every inch, you are totally screwed. Your trailer frame may actually fall onto the ramp. You are now talking about lots of physics to overcome. The burning smell you sense will be tires, clutch or tranny. You need to find out exactly what your launching weight will be. Add in the trailer, gas, etc.
