My opinion from
racing and cruising is that DDW is fastest VMG without a
spinnaker. And sailing angles (eg jibing downwind) is faster VMG downwind with a
spinnaker.
Just clarifying as above folks aren’t clarifying which
sails for DDW vs angles. Reason is that to sail a hotter angle with just main and jib/genoa requires 120-130 AWA which is too much extra distance to make it worth jibing. In those cases wing on wing is slowest through
water but most efficient DDW VMG.
A dedicated spinnaker or assymetric chute comes alive with only a small amount of heading up from DDW. So then angles are better for DDW
destination.
All of this from
monohull experience so maybe different on cat.