Originally Posted by hommes90
Why above the tarp? And why "especially" with the Big Mamajamba?
It prevents chafing of the tarp fabric against the ridgeline. I've seen it argued both ways: one school says that the CRL will help support the tarp against things dropping on it (snow and branches) if run underneath the tarp, while the other says that the CRL won't do much of anything except rub a hole in your tarp fabric so running it overhead is desirable.
With the BMJ, it has doors that can be closed. Since you can run the ridgeline over the tarp, it helps to have that out of the way when you close the doors. At least, that's my assumption, and you know what they say about those...
Personally, I run my ridgeline above the tarp. However, I don't have to worry about snow loading here in Florida, either. YMMV.