Originally posted by bearfoil ...
The V/S was semi submerged when spotted, its colors probably difficult to discern. The structure gave me the impression of never being 'proud' of the surface, and I assumed it acted as its own sea anchor from loss to discovery. BEA stated that the Rudder was flapping, and had no resistance to pressure in its axis of sweep. I do not think it "sailed" at all.
Bonjour mon ami. As you have stated, the V/S was semi submerged when it was located, though the total volume submerged was about 60%. Some of the lower void spaces between the ribs had been breached, and along with the weight of the attached clevis joints, the fin adopted a bottom heavy attitude and the top to bottom trim was about 5°. This resulted in the top of the fin being clear of the surface by around 1 meter.
The BEA's description of the rudder was for the "in air" condition, but the "in water" condition was modified by the application of Archimedes' principle. As I have stated previously the V/S found itself in the water floating portside down, and flooding in the lower sections of the fin caused the line through the rudder hinge joints to sink deeper, especially at its base. This sinking condition was overcome by the bouyancy of the rudder, and the rudder moved to its maximum physical position of 35° to starboard. The overall effect was that the trailing edge of the rudder was level with the sea surface and around 2 meters above it. This condition is clearly evident in the low resolution screenshot taken from the BBC2 documentary where the fortuitous sun angle provides suitable shadow, and is reproduced below.
Another couple of screenshots from the BBC2 documentary reproduced below, may help with visualizing the manner in which the V/S was floating.
So, mon ami, the fin/rudder combination floated, had a breached buoyancy condition which provided a form of keel, and the rudder provided the surface area for the wind to interact with.
Apologies for the delayed posting. A family members house moving venture delayed proceedings.