Re: can our truck tow our boat?
Not sure on the year of your boat, but a 27' Larson according to Nada should be about 5800-6500 lbs. Add to that a trailer (even an aluminum) and your approaching 19K. The truck as said is rated for 8400-9000 lbs. That rating is not the max it will tow, but the max recommended. A truck rated to tow 9000 lbs, with a good brake controller, weight distribution hitch, and a smart driver will tow 10000 lbs without being dangerous.
The 1/2 ton = 5000 lbs, 3/4 = 7000 lbs, and 1 ton = 10000 lbs is a good rule of thumb, but far from a maximum. Now talking about someone not keen on towing, or without proper equipment, I say stick to this. But someone who knows what he is doing and has all the safety stuff I say don't be afraid to approach the max load of the truck. It obviousely is less safe in a panic or accident situation, but then again towing anything is.