[pwd72s]

From the article...what I tried to say in my post, but conveyed much better here:

"2. Ballast
The height of Bayesian’s mast was of course considered in the overall design of the boat by Perini’s engineers. To this end she was equipped with an extra 30T of lead ballast in her keel box (we’ll come to that in a bit) compared to the 56m ketch rigged sister ships. This was to counter the extra mass, higher center of gravity and higher center of effort (from sailing forces) that the sloop rig created.

The main lead ballast was contained in a more or less rectangular box (keel box) attached below the canoe shaped part of the hull. The precise mass of this ballast I do not recall, but it’s probably around 200T or so. In the center part of this box there is the moveable keel, which weighed around 60T and extended almost 6m below the keel box when lowered. This arrangement means that the majority of the righting moment of the vessel comes from the main ballast… the moveable keel acting more as a centerboard to reduce sideslip under sail (leeway)…"