Steve,
Perhaps the reason the topic always seems to dilute, degrade, get lost is the lack of proof. On your request, I stepped up to the plate and gave evidence of my proof.
Now my numbers are not as grandiose as some others' claims, but mine are real. And mine definitely show that sailing in the ocean is much different than on a protected waterway that enjoys both flat water and unrestricted flow aloft.
The real world can be a challenging place and I am showing what I have been able to do in the ocean. Those guys who crossed the atlantic in 13.5 days deserve more than to be called slow. But there RECORD pace proves that you don't sustain 20 or 30 knots for very long.
Yes I would have been faster at times with less weight. There are times when more cantilevered ballast would be helpful too. But you just do what you can do at the moment.
Attached is a picture of a 20 nautical mile track across the Anacapa Passage and the Santa Barbara Channel. It crosses through the mild end of a place locally known as "Windy Lane."
The (blue) highlighted portion of the track is 15.7 nautical miles and was covered in 1:18:40 hours. Average speed is 12 knots. Now I'll describe the conditions and point of sail:
There were two of us on a Mystere 6.0 (narrow model). We had a soaking wet heavy spinnaker on deck. We had about 80 pounds of supplies. We had 25 knot wind on the beam with 4-5 foot steep combined seas striking us from abeam, that would forbid every attempt whatsoever to hike out beyond the gunwale. The jib was furled. We sailed "main only" with the main traveler eased fully or almost fully. The downhaul was fully hardened and the mainsheet hardened nearly to maximum.
Twice during the run (you can see the deviations) we had to head off to capture and rescue a cargo bag that had escaped its hold-down and was skipping under the trampoline, pulled by its safety tether.
I made this crossing with two other cats. The Inter 20 sailed it with the jib sheet cast off and jib flailing. The Hobie 18 sailed it with a furled jib and endured one capsize; after which he sailed "jib only."
Five of the six sailors were 15+ year catamaran veterens. All six sailors said that it was the wettest ride of their lives. When you can't get out on the trapeze, EVERY bow strike is a powerful blow of heavy water to the face. This slows the boat damatically as the "face brakes"

work to rob power.
GARY