The results of the ARC does not say much about the performace of the boats, most crews are cruisers, not racers, family crews that will enjoy the journey, not to compete, with heavily loaded boats.
Sailing between Thailand and Europe with a crew of Chilean racers we never use the autopilot and there was always someone who was tuning the sails, so we kept close to the maximum speed that the boat could give. We went two or three days after a flotilla of cruisers with which we share in Thailand, Sri Lanka and Maldives and arrived a day ahead of them. We kept the spinnaker all the time, even did spinnaker changes as the wind, while the cruisers reduced sails at night.
Yes I agree with you partially. First there are two ARC, one that is a real race (racing division ) the other that is just cruising with some racing in mind (at least for some) because there is also a classification. Most cruisers don't like to be overtaken more even if there are a classification and all boats from the cruising division are loaded.
They are all cruisers and they are going with the boat to the Caribbean and will cruise there for a considerable time. Regarding loading it is to be expected that a smaller boat would be much more loaded in a long voyage (regarding max load) than a bigger boat, for instance, a 38ft regarding a 55fter.
Here, like in any sailing situation, even racing, the quality of a crew is a very important factor but even with the best crew a slow boat will not go fast.
The point I was making is that a small cruising boat well sailed (and not raced, otherwise they would be on the racing division and I don't know if you noticed that I had separated the posts about each) can go as faster as many not so well sailed much bigger boats, but not all, it has to be a good small sailing boat. It happens that most modern production boats are good and fast boats sailing with trade winds.
Even so the performance of that Southerly 38 is only possible because it is a very well designed sailboat. It is an heavy boat with a swing keel, both things detrimental for performance. Only a very well designed hull permits the boat to be where it is, regarding all other boats, and a good crew too
Do you looked where the boat is? It is called Little Pea. First on the side turn out the boats from the racing division that had sailed out two days earlier.
World Cruising Club - Fleet Viewer
The performance Is so unbelievable that I had to check if the boat had sailed out at the same time as all the other cruisers...and this is not even the type of boat a cruiser that likes to race will buy.