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A number of America's Cup teams are believed to have investigated the concept of connecting the rig to the keel to bring the 20 tonne bulb back into line - effectively producing more stability and speed.
The question is have Alinghi cracked it with its latest boat SUI100?
One of the America's Cup teams has asked the measurer a series of questions in relation to a kind of swinging keel concept.
The rules state that only two appendages are allowed to move under the water - the rudder and trim tab.
A team has asked whether you can move the keel back up on the centre line where it should be, rather than allowing it to droop down.
Yachting commentator Matthew Sheahan said teams are trying to address the problem of the fin deflecting when the boat heels over.
"They are not allowed to have any device that moves the appendage back up but there's a suggestion that a number of teams have been looking at a way of linking the fin to the rig so that when the boat heels over or the pressure comes on the rig it tries to lever it up."
Sheahan said it is difficult to gauge how much the fin could be being moved.
"But if you could move it by as little as one degree you'd probably get about 3 per cent improvement in the your righting movement.
"Which is equivalent to three big blokes sitting on the high side. So it is important. It is not suddenly going to make them shoot off into the distance but it is important."
Alinghi's second boat SUI100 could be trialling the concept. It is understood the boat is not yet measured. The boat has a slight bulge at the top of the fin which may not necessarily be related.
"The worrying thing was I don't think SUI91 had it on there. So if it makes it quicker ... SUI91 was already quick to start with."
Sheahan thinks the concept has potential.
"I think it would give a benefit. I think enough people have looked into it to suggest there is a potential advantage there.
"Even if the team that has asked the question has come up against a brick wall and have decided not to go any further. it's still an interesting idea and is still an example of how designers are looking for every single thing they can.
"If it is a spoof it is still very interesting to see the level at which people are having to go to try and find an edge." In a team owners' press conference yesterday - which featured Alinghi boss Ernesto Bertarelli - the participants were reluctant to give an insight into what they might do should they win the trophy in July.
The winners, provided they have a challenger of record, can decide the timing of the event, its location and the type of boats used. Although this cup has yet to be sailed, debate has already begun on whether the boats should be changed, if the regatta should be held every two years - and whether the pre-regattas should continue or become part of the Louis Vuitton Cup.
"Let's enjoy what we've been able to put together this time around," said Bertarelli. "Because I think we've managed to hit on every single element that has made and will make this edition fantastic. Whoever wins the next time will have this wonderful problem."
