Crunch the numbers:
1.) The max tow rating for your truck.
2.) The estimated weight of the boat, trailer, fuel & gear. Figure on the high side when adding up these numbers to give you a cushion. My Seafarer weighed around 6K w/trailer.
When you determine the above numbers, if your on the edge of your trucks capability, what Blood stated above comes into play.
1.) Distance? Is it a ten minute pull to the ramp? If so, a marginal truck will probably be alright. If you tow long distances, like Smoky & KY Grady do with their Seafarer's, a heavier duty rig would be advisable.
2.) Hilly terrain or flat land?
3.) Ramp angle: if it's a mini Mt Everest, 4WD would be your best friend. You never need it 'till you REALLY need it.
The newer 1/2 tons can pull 9K or more. Your Seafarer will come in way under that. The older ones are rated for less.
Two more things that matter:
Make sure you have a hitch, drawbar, and hitch ball that is rated for the capacity of your Seafarer. I say this because I have a Dodge Dually with the Cummins Diesel. That truck, believe it or not, came with a 3500 lb hitch and the truck could tow 11K. What good is that?? I spent hundreds having it upgraded to the proper hitch assembly. Don't assume your hitch is sufficient for the task without checking. You are only as strong as your weakest link.
The other is your trailer. I talk about this 'till I'm blue in the face..Don't get stuck with a trailer that is undersized for the Seafarer. At minimum, it should be equipped with tandem, 3500 lb axles giving it a capacity of 7K. So many get marginal trailers and they have bearing problems, and a host of other glitches. It should also have electric brakes and heavy duty tires. Several on here have had good luck with Goodyear Endurance tires.
The Seafarer is a really cool package. Seaworthy, tow-friendly and it just plain looks cool.
I have rambled on here, which I often do. I got going, and just thought I'd cover everything I could think of that you may encounter. Good luck with your boat.