Cutting Edge Cat

Denby Browning | VOLUME 32, ISSUE 3
We accelerated so rapidly that I was nearly knocked off my feet!
Tony Longhurst has created one very unusual – and very fast – cruising catamaran.

Look at this, 24 knots – 24 knots!” called Tony Longhurst, pointing to the chartplotter aboard his brand-new catamaran, Kato, as we sped north under full sail in 25 knots of wind along the Gold Coast Broadwater.

Throughout our four hours together, Tony was excited about everything onboard this extraordinary new boat. And with good reason. This is a special catamaran that’s packed with leading-edge technologies, all designed to save weight and make life aboard as easy and simple as possible.

Longhurst had taken delivery of Kato just two weeks earlier. Already, he had sailed from the Sunshine Coast, where it was built, to Port Stephens and back.

Having recently retired from motor racing after 25 years in the fast lane, Longhurst still has a need for speed and Kato has been designed to deliver it – in spades.

But it’s not merely Kato’s straight-line speed that is astonishing. During our sail, Longhurst headed the boat into the tight confines of marinas and moorings at the southern end of the Broadwater – an area that powerboat skippers navigate with care. But a catamaran under full sail? Kato is so nimble that Longhurst was able to tack the boat at will, turning sharply and consistently.

Then there is the acceleration. Once in clear water, we came out of a tack with sails filled and accelerated so rapidly that I was nearly knocked off my feet.

SPEED – SIMPLE

Tony’s brief to designer Jeff Schionning, of Schionning Designs, was to take the concept of his previous boat, a fibreglass Schionning-designed G Force 1800, to the limit as a short-handed cruising catamaran capable of speeds up to 30 knots. Simple.

Julian Griffiths, of Noosa Marine, was closely involved in the design, with his team tasked to build the boat.

“Tony’s brief was that his new boat must be lighter and bigger and have much of what I call the ‘Hollywood’ of his G Force 1800 stripped out – nothing fancy, not even a water gauge in the galley,” explains Griffiths.

“Tony asked us to build a boat as big as our shed could manage … it measures 19.5m from stem to stern, that’s 65 feet in old language. When we closed the shed door, we had about 10 millimetres to spare.

“Kato is 1.5m longer than the previous boat, yet about 1.3 tonnes lighter and much more rigid.”

Kato is fast, certainly. And nearly everything about the catamaran has been designed to maximise speed. During an early shakedown cruise on Moreton Bay with rigging specialist Greg Christie from Everything Marine and Mark Bradford from North Sails, 27 knots were achieved.

Kato is built of carbonfibre. The topsides are carbonfibre, the mast and special boom are black carbonfibre, as are the dinette table in the saloon and twin tables in the cockpit – even the toilets and vanity basins in the bathrooms are carbonfibre. Oh, and the hull is carbonfibre, too, with an end-grain balsa-wood core.

WEIGHT CONSCIOUS

Weight saving is everywhere. The boat does include three electric winches as a minor compromise to cruising and comfort, though – one is on the mast for the main halyard, and winches on either side of the cockpit are for screecher and jib sheets. The main sheet winches are manual to save weight – electric motors and the heavy cabling could add 20kg to each.

The steps from the cockpit to the deck are high, not for the faint-hearted. The helm is stand-up only, with a pedestal nearly a metre above the cabin floor that sees the skipper’s head pop out of an overhead hatch – you can just see him looking ahead in the photo, to starboard.

The mast and boom are an interesting hybrid. The mast itself is almost pure racing, while the boom is almost pure cruising and includes in-boom furling. When under sail, every possible line is tucked away inside the ‘canoe’ of the boom to reduce windage.

“I learned many things from my days in motor racing,” says Longhurst. “One was the importance of reducing weight. Another was windage. Lines on deck add windage, especially when you are running at more than 20 knots.”

The rig was designed and built for Kato by Southern Spars, a New Zealand-based company which builds rigs for sailing megayachts and maxi-racers. Kato’s rig was designed in Sweden, components were built in South Africa and New Zealand, and it was brought together and mounted by Everything Marine at The Boat Works, on the Gold Coast.

A hydraulic ram is fitted under the mast. It pushes the mast up to attain maximum beneficial tension in the rig, which has a single spreader design.

The sails presented a challenge too, both for Southern Spars and the sailmakers at North Sails.

“The sails are made from our 3DI composite used on Volvo ocean racers,” says North Sails’s Vaughan Prentice. “We worked closely with Southern Spars to devise a structure that would maximise performance and suit the roller furling. Parts of the project had never been done before. We all learned from the experience.”

The mainsail, black of course, is square-top to maximise sail area and performance. There’s a small compromise involved with the structure, though: a square top sail requires a ‘gaff’ or angled batten near the top, so the sail will not completely roll furl into the boom canoe. Instead, the last metre and a half must be hand-flaked and tucked away into the boom.

Two sails are mounted forward of the mast – the aforementioned screecher for downwind sailing and a jib. The screecher is another nod to short-handed cruising – it’s a compromise between a spinnaker and a flatter reaching sail that, as a billowing sail, does not require a pole nor the additional lines that are needed to control a spinnaker.

POWER APLENTY

The non-sail power aboard Kato is as extraordinary as the carbonfibre technology.

“Originally, we discussed outboard engines that could be raised when under sail to stop drag,” says Julian Griffiths. “But there are inevitably a lot of issues around outboards on a boat of this size.

“So we began researching options and finally settled on an amazing pair of electric motors that include hydrodynamic saildrive legs. Each engine and drive unit weighs just 46kg and, of course, we’re also saving the weight of fuel.”

The all-in-one Oceanvolt electric engines and legs can generate 15kW (45hp) of power each. They can push Kato along at 10 knots flat out, which will drain the eight 200Ah lithium batteries in about two hours. Not that Longhurst ever expects to run his engines for two hours at a time – sailing is quieter and vastly more fun.

Kato carries an 11kVA diesel genset and about 40lt of fuel, essentially as an emergency backup.

Brad Stack, from Edge Electrical, spent many hours over the past 12 months researching electronic systems for Kato and the result is a combination which makes the boat essentially self-sufficient. There is rarely a need to run the genset, as the boat simply uses its systems to recharge itself.

Kato’s electrical and electronic systems are highly integrated. The engines require 48V power so the entire boat is wired for 48- and 24V systems. As well as nine 200Ah lithium batteries – eight for the engines and one house – there are 15 special pliable solar panels on the cabin top, shaped into the cabin profile so they can’t be seen except when you are actually on the cabin top. The panels are non-skid and robust, designed to be walked on. Combined, they generate up to 2.25kW whenever the sun is shining.

TURBINE POWER

On top of that generating capacity, the Oceanvolt system has a special capability. When Kato is under sail, the saildrive propellers can turn the engines into turbines, generating electricity instead of expending it. At fast cruising speeds of around 20 knots, the system will generate between two and three kilowatt of energy, which is pumped back into the batteries. This system is now available from Australian Marine Wholesale, Coomera.

The same simplicity is evident throughout the boat. In fact, it appears positively spartan.

The saloon includes white U-shaped lounge seating around a black dinette table. The U-shaped galley on the port side of the saloon area is marked by clean, clear benchtops. There are two top-loading fridges and a freezer aft and two drawer fridges in the galley. Stainless steel twin sinks are to port and a three-burner gas cooktop is on the starboard side of the galley. A gas oven is built in below. The carbonfibre of the many drawers and cupboards is hidden by timber-patterned veneer.

The two hulls house the accommodation, with guests to port and owners to starboard. The layout of each is essentially identical – east-west double beds amidships set inboard and up three steps. Even these are carbonfibre, coated in the same veneer as the galley furniture.

Forward, on the port side, are two modules that could be sleeping berths. Aft on either side is a bathroom – slightly larger on the owner’s starboard side – and beyond that, through a door at the aft of the shower recess, are the engine rooms. Except there are no engines. The engines are under hatches in the floor.

The port space includes the genset and a small clothes dryer. On the starboard side is a water-maker and air-conditioning system which feeds only the master sleeping quarters, as the boat is designed for flow-through air. The space forward of the bedroom on this starboard side is a storage area for fishing rods and watersports gear.

Immediately beside the companionway on the port side is a pantry and, on the starboard side, a cupboard with power and USB ports for charging all the gadgets that modern life requires.

Our run north along the Broadwater complete, Tony turned Kato into the Coomera River, heading for The Boat Works yard where it was due to be lifted out, weighed and serviced. And even in this narrow waterway, Longhurst wanted to remain under sail.

HE WHO DARES …

“Bet you a dollar I can get her all the way up to The Boat Works under sail,” he dared. I declined.

The Coomera Rivera is a no-wash zone, which means up to six knots for power boats.

“Kato just won’t go that slowly,” said Longhurst as we overtook a power sportscruiser.

At 24 knots, Kato makes something of a wake, but at eight or nine knots the surface is barely disturbed.

We did slow to less than six knots briefly – when both mainsail and screecher luffed for a minute or two.

When we arrived at The Boat Works, we docked in the Travelift bay. In the past three years, Longhurst says, business has tripled in size, with over 50 marine professionals on site promoting the same ethos and values of true customer service. It is running so smoothly that he can afford to focus more on his passion for sailing.

“We have a great team and a fabulous group of businesses working here. It’s more like a family.” A tenant says Longhurst is often seen scooting barefoot around the yard on his skateboard … the need for speed can take many shapes.

KATO G FORCE 2000 SPECIALE

LOA: 19.50m

Beam: 6m

Draft: 0.575m

Displacement: 10.5 tonnes

Mast height: 22m

Mainsail area: 118sqm

Headsail area: 57sqm

Power: 2 x Oceanvolt SD15 electric sail drives (15kW)

More information: The Boat Works, tel: (07) 55 000 000. Web: theboatworks.com.au.


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