On 5-Feb-2006, "John Weiss" wrote:

Two doubles fit on a car top; 4 singles do not...

I've seen four singles on a cartop using J saddles. It can be done. You'll need a
vehicle that can handle a long crossbar though.

May be faster due to length

Doubles can be faster because they have two paddlers. Length is not the great
contributor to speed in spite of common misconceptions. Doubles are only a
few feet longer but may be over 50% wider.

Mike