Yes indeed Jake, the diagram suggests that the two side foils are connected construction-wise.

In fact that would be logical, because you only need the foil on the leeside (and moreover at its utmost lenght).


Here's another explanational vid:

http://www.safran-sailingteam.com/media/new-foils-greater-speed-and-reliability-20160922
And go to the link on the right side for the video.

But this vid also doesn't mention the exact foil-construction.

Great stuff Ronald, thanks for posting.

In that video (above) both foils seem to be fully extended at the same time, so I'm guessing they are separate pieces and one or the other (or both?) can be retracted independently? Or was that just the experimental phase and for the race they have a one piece foil?

The earlier drawing you posted made it look as if it were a one piece type where when one side is out, the other side is retracted, but the video has both out at the same time.

I was surprised when the announcer said it increases the speed by... 2 knots. I would have thought it would have been much more than just 2 knots.

What about the rumors that Alex had a 'spare' on board? I believe there was a report that said his boat had some features that allowed access to the foils without going over the side...?

If the foils were joined in the center somehow, it might allow one to disconnect and remove the broken side and connect a new one in its place...

However, I would presume that these foils are have a unidirectional shape, so if you were to have a 'spare', you'd need both sides since you couldn't carry just one and use it in either direction?

They would indeed by asymmetrical - no chance you could swap one for the other from side to side.

Although that diagram looks as if it infers it, I would also be very surprised if they are connected in the middle...there's too much of a maintenance headache to maintain if it were one and there really wouldn't be much advantage to connecting them together, structurally.

And me too - 2 knots? 2 Knots is nothing to sneeze at but it looks like it's definitely more at times.

http://www.safran-sailingteam.com/fr/video/15?shadowbox=1

Hope this link works. What you see is the upside-down safetytest for the Imoca "safran".

You can see that both foils are retracted in the hull for safety and protection reasons.

Which indicates that they are not connected in the middle.

Looks kinda like the lift provided by the canting keel may at speed may only increase the heeling force. Maybe that's why Alex has his more centered.

http://www.dailymotion.com/video/x557cd1_yann-elies-dans-un-grain-de-40-noeuds-vendee-globe_sport

That's what sailing looks like in 40-50 kts. Even on open water the waves break.

I'm sure it's way worse than the video shows. I remember spending a November aboard a merchant marine ship in the Caribbean (not the Southern Ocean) and going through a relatively shallow low pressure system on the return. We had HUGE waves and foam streaks across the surface. I tried on several attempts to take a picture of the bigger waves and the photos were pitiful. It didn't look any worse than a fresh day in Panama City Beach. I ended up just deleting the photos.

HB's foils definitely are not connected in the middle. His boat is the only one of the foilers to have more conventional deck-side exits for the foils, though I still don't believe there is any way to replace that board while sailing; board weight #'s have varied but ~160kg is in the middle of the range quoted, with 200kg being the upper end, plus the geometry is pretty prohibitive of changes.

Certainly exciting, but a little less so now that Alex has routed himself through the middle of a low and then the middle of a high while Armel has stayed south and in pressure. A damn shame as there was a solid drag race going at the front of the fleet for near a month! Still its anyones race, Armel has been runner up twice however so his shot at winning is probably pretty solid. A HB win would be a big upset to the French however, and really crank up the design efforts!

I haven't studied it to figure out why but I agree that video / photos rarely represent the size of waves accurately!

I'd bet it has something to do with focal plane. But maybe a photographer/artist has a better definition since I've seen some amazing photo-manipulations of scale...

But that's exactly my problem too.

I've 7 vids on YouTube ( search for: ronald reeder northsea) and none of them shows what I wanted it to show.

Big waves, excitment, etc.

I would be very thankfull for the golden tip.