Bluedog,

What is the GVWR on your trailer?
There should be a sticker on your trailer with this info.
Also, don't know what your state is, but it probably is on your regi.

Weight of fully loaded boat will be at least 4000, not counting the trailer.

I trailer 70 - 75 miles round trip every time I use my boat. If you are also a trailer boater, you should be looking into a beefier tandem axle. Your state may also REQUIRE you to have brakes at these weights.