Gunboat G4 with J foil daggerboards and T foil rudders
Very interesting news. Gunboat, builder of high-end racing/cruising catamarans, has promised the G4, a new all carbon fiber 40 foot long catamaran, in early 2015. The drawings and video have shown C-foil daggerboards and T-foil rudders. C-foils allow “foil-assisted” sailing. The C-foils develop lift and are capable of supporting most of the catamaran’s weight but will not lift the boat entirely out of the water. Since at least last Spring, however, there have been suggestions that Gunboat has something more ambitious in mind. They may be offering fully-foiling daggerboards, referred to variously as J or L foils, which would allow the G4 to fly like an America’s Cup AC 70, qualifying as the first flying cruising catamaran. Gunboat’s founder, Peter Johnstone, has said of the G4 — “It’s the baddest-ass coastal cruiser ever.”
In an interview with Sailing Anarchy from last May, Gunboat team member Rudo Enserink revealed the following:
SA: With the J-boards and T-rudders, this is looking like a full foiler. Is that really possible on a boat with bunks and a kitchen?
RE: Yes and no. We’re first going to build high-lift C-foils for safe but very fast foil-assisted sailing. The mildly asymmetric C-boards can be raked from -1 to +7 degrees and will be set at the factory for safe cruising. The lift of these foils maxes out at 80% of displacement, and advanced owners can play with the rake adjustment to optimize for purpose and conditions. One of the great things about C-foils is that you can leave the windward daggerboard deployed in all tacks. The hull and daggerboard casing structure is prepared for full foiling, as are daggerboard bearings and rudder bearings.
If there’s enough interest from the market we’ll develop an electronically stabilized full foiling package that will be available as aftermarket upgrade. The current concept for this is an L-foil and auto-leveling T-rudders.
A post today on Tony Hodge’s blog at Yachting World appears to confirm this, but is a touch unclear. The graphics on the post show the G4 sporting J-foil daggerboards, while the post text says “The daggerboards are C-shaped…”
The post also notes: In just 12-knots wind for example, the G4 should already be up and flying at a predicted 18 knots. One of the designers, DNA’s Mischa Heemskerk, who has reportedly had the foiling GC32 up to 37 knots, thinks the G4 is capable of another 10–15%. Can you imagine that? 40-knot plus speeds!
It will be very interesting to see how this technology functions on a catamaran with accommodations for cruising.
“It’s the baddest-ass coastal cruiser ever.”
For that read an accident waiting to happen. This type of vessel might be safe in the hands of a professional but my experience of accidents and their causes include poor maintenance, poor navigation, poor seamanship and poor recognition of capabilities. Recently I have seen a £750,000 pound motor yacht destroy a navigation buoy with severe hull damage because the owner was below making a cup of tea whilst the vessel was doing 20 kts on autopilot. He regarded himself as an experienced and competent sailor with paper qualifications in excelcis. And by the way what if the buoy had been a family yacht?
Although this was a motor yacht I have seen similar with yachts and catamarans. At these speeds the concentration and attention to detail is critical.
Vestas Wind? Top guys, ultimate damage.
And remember. Murphy’s law.
I agree. My guess is that most of the G4s will be delivered with C foils and any sold with J foils will be subject to all sorts of indemnification to keep the lawyers happy.
I look at those foils and I hear “snap.” The slightest touch on the ground and ping goes the carbon. I’m definitely not good enough for that boat. 🙂
I know that whether or not I am good enough (probably not) for that boat, my wallet definitely tells me that I won’t be ordering one any time soon.
hey, this cat looks very sporty, and the videos say lets fly ! NO engines allowed! If you are worried about accidents, stay at the dock ! Not me. Heck anything can happen, just like the guys doing the accross the atlantic row boat race. Something hit the bottom of their boat and spun it backwards. After checking the bottom of the hull they found a spike in the botton from a marlin bill that had punched through and broke off ! So if you’re chicken stay in the hen house, but if you’re a hawk then FLY !