G4: A quantum leap forward (and up)

Published on March 20th, 2015

The Gunboat brand of catamaran delivers premium comfort and performance, and while the founding premise was to produce world cruisers, their no-compromise approach has attracted some owners eager to test themselves on the race course. However, the brand is about to quantum shift up… literally… with their latest 40-footer, the foiling G4.

Equipped with showers, galley, and queen-sized beds on the topside, the underside of the G4 will have T-Foil rudders and L-Foil daggerboards – not your usual cruising boat blades.

The DNA Design Team from Holland, best known for their three-time World Champion DNA A-Class catamaran, has drawn the G4 lines. Mischa Heemskerk, 2012 A-Class World Champion and a mechanical engineer by training, has been responsible for foils and performance.

With the G4 sea trials soon to begin, Mischa provides an update on what to expect…

What are the performance expectations of the G4? Will the boat fully foil?

The boat will be fully foiling with the hulls about 60cm above the water. My expectations are for the boat to reach a speed of 40 knots on flat water. With the foils at minimum rake, it will damp the movements of the boat making it a pleasant cocktail ride.

How adjustable are the foils?

The main foil can rake fore and aft over 10 degree’s (-3 till +7), while the rudder can rake 4 degree’s (-2 till +2). Since this is a cruiser-racer, we have made the daggerboard case for the first boat extra long with three pre-set positions so we can move the daggerboard to the optimum balance point during sailing.

Are the concerns of foil damage greater than a multihull with non-foiling blades?

Foiling makes for higher speeds, but with the platform elevated, the concern of the hull taking the first impact is eliminated. Plus the foils are an amazing example of mechanical art, shape, geometry and construction. Since the boards have to carry the complete load of the boat, their construction and carbon quantity is very high which makes them strong.

When are the sea-trials planned?

The boat was built by Holland Composites in the Netherlands and has been shipped to St Maarten. I will be greeting its arrival on March 26, and our plan is to have the first sail on April 1. If all goes well we hope to race in the Les Voiles de St. Barths (Apr 13-18) and Antigua Race week (Apr 26-May 1).

How large a leap forward do you expect the G4 to be?

The G4 is a significant leap forward in the ability for cruising boats to maximize their sailing range per day. Using proven technology as shown in the latest America’s Cup, and by adapting details that we have since learned, the G4 makes foiling available for everyone.


G4 foils in production.


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