Genius? Not! wrote:

I've got the 5.5 foot box, so that might explain why its a little squirrely
when I'm backing. I'm getting better at the backing. The trick for me was
to finally give in and use the bottom of the steering wheel to direct the
trailer.

No shame in that.

The trailer tongue length, actually the distance between the hitch and
the axle, has more to do with it than your tow vehicle wheelbase. I'm
betting you can back your truck pretty straight without a trailer. I
used to have a little utility trailer that was a real pain to back
straight. The boat is a piece of cake in comparison. I tend to do better
with my head turned around looking backwards than using the mirrors.

Keep at it and you'll have it down in no time.

-rick-