Bill wrote:
The rack bars are manufactured wider than 48 inch but an installer can not
install them wider than the vehicle (this as explained to me). You can
purchase wider bars and replace the shorter bars with wider ones using the
same mounts. To get a better idea of how wide you will need, measuring the
boat at it's widest, times two, will give you an idea of how wide your bars
need to be to accommodate both boats. Depending on the vehicle, rack
placement may be close together so will end up to be under the widest part
of the boat. If you are able to separate the bars far enough so as to
support the boats at less than maximum width you may be able to get away
with the 48 inch bars.

A 48 bar rack can handle considerably more than 2, 24" wide boats. If
the outer cradles are mounted at the ends of the bars, you will easily
gain at least another 6" in capacity and possibly more, as the boats
will overhang the ends of the bars.