There are several things you need to look at.
One, what is the GVWR of your vehicle? This is the gross vehicle weight rating and it is the maximum weight your vehicle can carry including you, fuel, your friends, luggage, and a set of ski's strapped to the roof.
Two, what is the GCWR of your vehicle? This is your gross combined vehicle weight rating and is the maximum your vehicle PLUS trailer can weigh.
Three, what is the overall tounge weight of the trailered vehicle (100-300lbs?). This counts against your GVWR which will reduce the ammount of weight your vehicle can two because it cuts into your GCWR also.... Think of it like this. If your car weighs 3200 curb weight with a GVWR of 4000 and a GCWR of 6000.
You have to take 3200 + yourself + your friends + your gear and subtract that from 4000 (GVWR). What's left is the max tounge weight your car can support. Assuming you max out your GVWR (not recommended BTW, I'd only go about 80%) that leaves 2000 pounds actual towing capacity IRREGARDLESS of what your hitch reciever is rated for!!.
Now, there are other ways to cheat and remember this is all hypothetical. Now, let's say you and your friends and your stuff all weigh in at 3850 (we'll continue to use 4000 GVWR as an example). and your boat + trailer is only 1000. This brings you up to 4850 GCWR which is well within your vehicle limits BUT, BUT, BUT, you need to support 300 pounds of the trailer weight on the tongue! Now you have a problem because tongue weight counts DIRECTLY againtst your GVWR (not the same as GCWR).
The way around this is with a load equalizing hitch that uses equalizer bars and snap-up bracketry to take weight off the tongue and distribute it between the tow vehicle and the trailer. Just something to thing about if you run into this situation.
Finally, how are you going to STOP all this extra weight? If you're towing more than a couple thousand pounds (especially in a light weight car). You're likely going to need an electronic brake controller for actuating electric trailer brakes. This is gonna require heavy duty wiring and a special 7 blade trailer connector.
The most important thing is under any circumstance, DO NOT exceed the manufacturer's ratings for GVWR and GCWR unless you want to be a rolling road-hazard.
On the other hand, a good used mid'80s, early 90's F-150 can be had for dirt cheap if you do some digging and will solve all your problems in one fell swoop. You'll be able gaurenteed to have enought torque to yank that boat back OUT of the water AND if you're only going 1 or two miles back and forth to the boat ramp then the shitty gas mileage should't really matter too much (plus everybody need at least one truck sitting around for doing 'truck stuff').
Probably haven't helped as much as I've confused the issue. Just want to make sure you look before you leap.
JR..