I can still recall the sensation. The uneasy movements in the boat, when the swell from the passing hydrofoils rolled into the small harbour behind the Little Mermaid in Copenhagen, where my parents had their first boat. As a young boy, it was fascinating to watch how they – as soon as they were out in open sea, increased their speed and majestically raised out of the water and up on their foils, before disappearing in the horizon towards Sweden.
That was forty years ago. Of course, the idea of using foils to reduce a ship’s wet surface and hence its friction through the water, is nothing new. In fact, the first hydrofoil-patents were granted as far back as the late 19th century. Yet up until the second World War, foiling remained largely limited to motordriven vessels. Even if several yacht designers and boat builders experimented with foils during the following decades, no one managed to build constructions feasible for anything but one-off multihulls, designed to break records.
The past 5-10 years however, foils have had a rather remarkable renaissance in sailing. It’s not that we’ve learned more about hydrodynamics, but we’re able to make still more complex calculations, test foil-designs in virtual towing tanks and above all, the materials at our disposal are now stronger and lighter than ever. Today, foils seem to show up everywhere. From the latest generation of the Vendee Globe IMOCA 60 racers and the Americas Cup catamarans, through more ordinary performance cats and all the way down to the tiny, but amazingly fast Moth dinghies.
Just a couple of years ago, the Quant 23 came out. Technically speaking, it was the first keelboat with foils. It is a fairly small scow design however – a Flipper dinghy on steroids, rather than a “real” keelboat. But if you thought that foils for monohulls were still purely a boutique yacht design fad, you’d be wrong. Beneteau, one of the largest sailboat manufacturers in the world, has recently followed suit with the Figaro 3. This third edition of the Figaro (a design that dates back to 1990) will be a 35.6’, production monohull born with foils.
The advantages of foils are simply too many and too big to ignore. I for one, am certain that foils are here to stay and that they will – in some shape or form, trickle down from the current racing designs to cruising yachts. They’ve already found their way to cruising cats (e.g. Gunboat’s G4) and they will find their way to cruising monohulls too.
The thing is, it’s not all about speed through lift, a stronger righting moment and reduced drift, it’s also about comfort. Depending on the shape of the foils, they can significantly attenuate the movements of the hull and increase the feasible wind span for a yacht’s sailplan. Stronger wind equals higher boat speed and hence, increased righting moment of the foil. In other words, the boat will be able to carry the same sailplan in stronger winds. Foils also allow for weight reduction, since the keel ballast required to stabilize the boat is reduced.
Sure, the challenges are many. Like daggerboards, outriggers, bowsprits and other yacht design features that serve to optimize the boats sailing capabilities, foils are just hugely impratical. The question is whether the yacht designers and boat builders will manage to come up with foiling solutions that are easy to handle; can be hidden away within the hull of the yacht – for instance when docking or motoring; are sufficiently dependable and finally, can be manufactured at a price that cruising sailors are able and willing to pay.
What is your take on the foiling frenzy? Are they here to stay? If so, when will we be seeing them on average cruising yachts, and in what shape?
As always, I’d love to hear your thoughts.
PS. If you missed the last blog post (challenge #2), you’ll find it right here.
Image credits: We have borrowed the image of Banque Populaire featured on top, from Jean-Jacques Abalain, Domaine de Drogant. You can find the original image here. All rights to the photo belong to Jean-Jacques Abalain. The image of the Moth dinghy inserted in the text, is one we’ve borrowed from Paul Nelson. We have cropped it vertically, to fit the layout of the blog. You can find the original photo here. All rights to the photo belongs to Paul Nelson.