Why 7ft Primary Hose for Doubles?

[Dr Wu]

I hope this is the right forum for this question.

I am new to doubles and have begun the process of educating myself and piecing together a rig.

Can someone explain to me why the primary hose needs to be 7ft long? In an emergency situation diving a single tank where my buddy needs air, I would dish off my primary to my buddy and breath my backup, no? And my backup hose is longer than my primary. Why is the primary 7ft long in a doubles setup?

Obviously I'm new to doubles, but I'm trying to figure it all out. Many thanks!

Stick to singles.

 

[Randy43068]

Tuck the excessive hose into your waist belt or strap if you don't have a can light.

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