: Will my underdeck bungies secure my hatches while traveling at 55 MPH into a
: 95 MPH gust of wind from the semi that just past in the oppisite direction
: on a two way road with a 40 MPH crosswind in the middle of nowhere?

YES !

: Or do
: I need to add external straps for peace of mind?

naa... I wouldn't, I don't, & I didn't, & they always stayed in place.

: I would hate to see what
: everything would look like when I arrive to find the hatch had been
: whipping around at the end of the safety strap for who knows how many
: miles!

Even if they do, you will hear it/see it/know it. but they wont.

: Doug

Erez