Murray Ross the designer and his cat

We've all seen small sailing cats screaming downwind under gennaker at faster than the true wind speed but when you're on a 16m cruising catamaran and the wind instruments are making such audacious claims, it's a more highly loaded kind of thrill.

First of all, the instruments are speaking the truth. There are enough electronics on Isis, the new sailing catamaran from Pine Harbour, to, quite literally, meet the meteorological requirements of a Volvo Ocean Race yacht or to satisfy an America's Cup syndicate and they all interface with each other. If one were lying, the others would quickly highlight the offence.

Secondly, this cat was conceived, designed and built by Murray Ross: yacht designer, Olympic sailor, many times national and world champion, Whitbread and Volvo Ocean Race navigator and weatherman, America's Cup weather expert.

So, yes, we were flying under asymmetric spinnaker towards Gannet Rock, on the seaward side of Waiheke Island, at more than 16 knots, despite there being just 12 knots of wind. The loudest noise was the rapid wake off the transoms, a sound that normally follows launches around. As for calling the puffs - the puffs were calling us,as they tried to catch us. Instead, as we caught up with puffs ahead, the acceleration threatened to trip me off my feet, with a delicious fast sound, and the rapid ticking up of numbers on the displays. We were seriously covering ground - as shown by the big navigational screen in the saloon, the small screen in the saloon and a small screen in the cockpit.

I took the helm and it was smooth as Mylar, with total sense of control but I'm lousy at helming multihulls - I never get the hang of maximising the apparent wind advantages, so after a while I handed it back to someone who could put bigger numbers on the screens and bring back those acceleration thrills.

Instead, we played charter guests and hung out on the trampolines while the huge blue kite floated above us; beneath us, the water rushed between the two hulls like rapids in a gorge.

Many times I have slogged endlessly towards Gannet Rock but, suddenly, it was sliding past us at 16.3 knots so we tacked and headed back for Oneroa, to anchor for the night. On the screens, our track tacked, too.

Sailing upwind was unsettling initially: the apparent wind was just tipping 20 knots - it was almost hard work to go forward along the sidedecks to the trampolines. Coming back, it was almost too easy to keep going, right off the transom. Later, I was below deck during a tack when the sheet came off the winch above me like a bullet. The loads on the deckgear are huge and carbon boats magnify every decibel.

Isis is Ross' latest variation on a sailing career. Multisails Ltd was established to build her and charter her: one or two couples, max, on overnight or offshore trips.
Ross' weather technology, sailing experience and a fast boat will be a charter option hard to beat. "I'd like to take people from New Zealand, pick the weather and get to Fiji in three and a half, four days," he says. "Spend eight days cruising in Fiji and then put them on a plane home."

For our trip to Waiheke, Ross had invited long-time sailing partner Colin Booth and some of the build team for the first few hours, but he has set up the boat for two-handed sailing and the next day, he and the hostess demonstrated the ease with which they run the boat.

A big part of that is six electric winches, electric in-boom mainsail furling, and furling headsails. He also has a clever autopilot.

For the mainsail hoist, Ross took the helm while his hostess applied the foot pressure to one of two electric winches at the central console and up went the fully-battened mainsail.

The cockpit is huge, with helmstations up step either side and wide flow-through into the saloon. The only structure in the middle of the cockpit is the console for all main control lines - prod, jib and main halyards, jib and main furlers, topper and rotating rig. They enter the jammers at the central console from beneath the bridge deck and loop tidily into a large bin.

Like most professional sailors, Ross is far more safety conscious than most amateur sailors and his Volvo Ocean Race experience has been a big influence in designing Isis for offshore. She has the highest possible survey rating.

"One of the biggest things I've taken onboard is just how rough it can be out there," he says. "I've been very aware I don't want any problems in those conditions."

The worst, he says, was trying to sail around Cape Campbell off the South Island on a Whitbread yacht. There was an 80kt southerly with the swells conservatively estimated at 14m. Worse, they were closely spaced.

"In my experience the wind does not hurt you too much," Ross says, "it's the sea conditions that can do the damage - to you, physically and mentally, and to the boat."

With his in-depth weather knowledge and onboard equipment, plus the boat's speed, it's unlikely Ross will get caught out but if he does, he'll be prepared.

Ross is well known as a monohull designer. Apart from Daintry II, the powercat tender for America's Cup syndicate Stars and Stripes, this is his first multihull but he says the approach is the same.

"It's still basically aerodynamics and hydrodynamics. Structurally, you haven't got a keel trying to fall off but you've got two hulls trying to fly apart.

"The loadings are pretty awesome [on a catamaran]. Personally, I don't find there's any great mystery in producing a good cat. I think the key is a good structural design to keep the weight as low as possible."

The best way to control weight was to control the build, so Ross contracted to Multisails Ltd at a factory in Pine Harbour and hired a team of builders. Isis' contruction is mostly carbon fibre, Nomex foam and epoxy resin, to keep her light. Multisail Ltd built many components that would normally be sourced outside: the mast, boom, forebeam, seagull striker, the headfoils for the jib and storm jib, steering wheels, centreboards and rudders. He estimates he saved 2kg over a commercially built forestay foil and more than 20kg over an aluminium one.

They worked closely with KZ Marine and built a Leisurefurl boom to KZ specifications. The interior cabinetry, even the ironing board, is carbon.

There are fibreglass and Kevlar in the outer hull skins for impact resistance and carbon with fibreglass laminate in the decks.

Amazingly, this 16.5-metre giant weighs in at just 8 tonnes. "It's not a lot different from the Volvo boats that are perceived to be out and out racing boats and they survive sailing around the world," Ross says. "This is similar - performance boat that can handle those conditions because of its structural technology and design."

The main factors in performance, apart from weight, are the cat's hull design and its rotating rig and sail plan.

Having chartered a 46ft cat in Corsica, Ross knew multihulls suited chartering but he wanted more speed and more space. Designing a cat 3m longer, 2m wider and using more sophisticated materials to make it lighter solved all problems.

Using Maxsurf software, he says, "I started with a blank screen and developed several hulls and modified them many times. I went through 101 calculations before I settled on the final design."

The hulls reflect a shape above water halfway between what is optimal for performance and what is optimal for cruising, at a length to beam ratio of 14:1. Subtleties in rocker shape, distribution of buoyancy and a reverse sheer reflect performance and cruising attributes. There are two watertight bulkheads, fore and aft, in both hulls.

As for the carbon, rotating mast: Ross designed it for efficiency "when it's got a mainsail hanging off the back of it", but for inefficiency when presented as a bare foil rotated along the centre line of the boat. This was to ensure that if he was berthing the boat, or reefing down in strong winds, that the mast wouldn't take over and sail the boat. The mast chord is 2:1 fore and aft, 580mm deep and 250mm wide up to the hounds, when it tapers significantly to present less 'sail area' aloft.

However, rotating rigs are confusing for a wind transducer sitting on top of them, trying to send true wind data to the autopilot, which may be in charge of a cat surfing down waves at 30 knots.

Therefore, Isis has wind transducers mounted high on towers on either transom, and uses the windward transducer, as the mainsail will be sheltering the leeward transducer. After every tack or gybe, a crew member flicks a switch to link in the new, windward transducer.

There is a similar switch for the transducers speed log, to ensure the speed is read from the leeward hull; if the windward hull is lifting, it will also send confusing speed data. Again, the correct information is important for the autopilot and GPS

Chartplotter.
The autopilot can read from apparent or true wind, a relatively new development in autopilots. When surfing under asymmetric spinnaker, eg, it needs the immediacy of true wind information.

The rotating mast sits in a shallow, greased ball and socket, held in place by an alloy spigot to prevent it from popping out in big seas. The rigging is Aramid, a reflection of Ross' Volvo and America's Cup days.

"The mast can be rotated up to 65 degrees off centre line. Upwind, it's rotated from 23-28 degrees more to leeward than boom."

Self-tacking jibs are popular on cruising cats nowadays, but Ross has avoided them - self-tacking jibs are smaller, requiring the mainsail and mast to be bigger, which went against his attention to safety and short handed ability. He also felt the bigger jib provided a more balanced sail plan with a lower centre of effort. There are inboard and outboard sheeting tracks on the cabin top.

Isis' rudders resemble those on some of Ross' monohulls but only one-third the size. They are carbon construction, with a fairly fine chord thickness for low drag. The bearings are in a box so the whole rudder can be raised for beaching the boat or for repair.

The two centreboards are designed to perform best upwind because they are pulled halfway up when reaching and downwind. A nice touch: when fully up, they sit flush with the deck, rather than protruding above it.

For cruising, Ross wanted just one masthead spinnaker and went for a conservative girth, fairly flat sail, which he can carry up to 13kts apparent - the broader the wind angle, the higher the wind strength in which he can carry the sail. The code zero hoists almost to the masthead, and flies in up to 18kts apparent, on a Sea Rig furler.

The storm jib, too, is on a Sea Rig furler and hoists to the top of the lowers. Offshore, it will be hoisted permanently, furled, as it stabilises the mast like a baby stay.

Ross explained this as we sat enjoying another aspect of Isis, the supreme cuisine. We were also asking numerous questions about his sailing adventures - when charterers are taking a break from the thrills of fast sailing and have wiped the last speck of crayfish from their lips, they can hear, first hand, the stories of an amazing sailing career.

Eye in the sky

The nav station on Murray Ross' new sailing cat, Isis, could satisfy the requirements of an ocean racing yacht. Ross should know - he's done three Whitbread/Volvo races as navigator/weatherman and looked after the weather for two America's Cup syndicates.
In setting up Isis for offshore charter work, he sees weather, navigation and communications ability as fundamental to safety and pleasurable boating.But, it looks complicated. Kevin Moggach of Seatrak Electronics Ltd explains the process.

"You start with PC integration and a good functional scope," he says.

"Customer input is essential for a good installation, which is also dependent on available space and budget."

The computer runs charting, communications, internet and even entertainment courtesy of DVD.

Isis needed a satellite phone system for offshore communications and email, which required a data connection. In this case, that's the new Fleet 33, a phone system that allows the user to be online to the internet, viewing weather satellite images for example. The user pays for data transferred to and from the internet, on a per megabit basis - no air-time-per-minute costs.

The computer runs Raymarine software, RNS 5.0, which interfaces the instruments through HSB2, Raymarine's high-speed data system. This innovation gives Ross an asset he didn't have during his 1997 Volvo Ocean Race - the ability to overlay information from radar or weather forecasts over the chartplotter. The system is also much less expensive to use and onboard hardware is more compact.

He demonstrated the radar overlay as Isis sat in her marina, Zoomed in, the radar picked up masts of neighbouring boats on the chart of Pine Harbour.

Theoretically, Isis could be berthed on radar. He can manipulate the image so the radar or the chart dominates.

Good interfacing means all instruments work happily without interfering with each other.

Seatrak's first task is to design the installation. A boat's nav station may include many brands of instruments, and different brands use different electronic formats. Interfacing uses the appropriate data converters and interface boxes to make the formats compatible.

Next, Seatrak ensures there is enough computer power to drive the system. It then tests the system and adjusts as necessary before installing it on the boat.

Isis' navigation station has two screens: a 37in Sharp LCD screen used primarily for entertainment but also for navigation and a 19in LCD screen for navigation. Ross can have one eye on the radar chartplotter while dealing with emails on the smaller screen, for example, or show a movie to charter guests while running the chartplotter. When sailing offshore, he will be able to check the radar on the big screen, and flick through different screens using the portable, wireless keyboard from the comfort of the settee.

Isis also carries a sextant.

Weather
SkyEye is a large component of Ross' weather forecasting technology. Say he wants to check out the sea off Cape Reinga. SkyEye allows him to access a satellite view of the sky over the cape and zoom in for detail. At its best, the satellite image will give sea temperature - useful for fishermen, a thermal image of cloud cover and measure of rain per hour, wind direction and strength, and sea state.

He can also look at the satellite's track. If the satellite went right over the top of Cape Reinga, the information is a accurate as it can be. If the satellite was following a path over the mid-Tasman, the information for Cape Reinga will be less detailed. However, SkyEye will show when the next satellites are coming through and what their paths will be so he can ensure he gets the best image.

A navigator can overlay detail such as wind strength and direction from SkyEye and weather websites, in real time or in future predictions, to work out the best route for an offshore voyage. It may be better to sail upwind for a day, to get fast sailing from then on, rather than settling for the best option on the day but suffering less favourable conditions later.

What really impressed me, an observer, was that it seemed easy to use.

A favourite instrument is the digital barometer, which displays the recent barometric history and temperature, either in hours or days, to show the trend.

Auto Helming
The biggest improvement Ross has seen in technology, he says, is in autopilots and gyrocompass. Previously, the autopilots worked only on apparent wind information. However, modern boats accelerate and decelerate so quickly, taking the apparent wind with them, that it can cause an autopilot to put the boat into a crash gybe.

Sailing to true wind angles may give a better course, and the crew can take care of the trimming.

Ross has avoided forward-facing sonar, preferring accurate depth readings. In the tropics, the first indication of a reef ahead may be when the depth begins to shallow from 1000m.

Communications
The basis of the communications is Fleet 33. The phone system has two lines, representing cellphone and satellite technology. Between them, they provide worldwide coverage. As long as Ross has the correct Simcard, he will pay only local rates, anywhere.

Isis' fax doubles as a colour printer for anything on the screens, whether it's a weather map or a digital photo.

Please click here to request a DVD of the charter experience.

Multisail Ltd
P O Box 223 Paihia
Bay of Islands, 0247
New Zealand

+ 64 21 987682 Boat


Skipper Murray Ross:

Marketing Sharron Ross: