FB2 Vapour Shroud

What are people's idea's on how to use a Vapour Shroud?  Shield 2
protection 
for shield 1 cost and mass is nice, but since it blocks your fire as
well 
when in operation when do you use it?

Oliver Dewey Upshaw III
odupshaw3@hotmail.com
odupshaw3@cs.com

"Ms. Wolversham, you are authorized to return fire!"
David Weber   The Short Victorious War