Fastest maxi in the world?

Frank Pong's new 118ft Maiden Hong Kong could be the first supermaxi to take on Mari Cha IV

This article follows on from last week's interview with designer Juan Kouyoumdjian

At 140ft long and with her towering schooner rig Robert Miller's Mari Cha IV rules the waves when it comes to singlehulled speed under sail. However the first serious challenger to this mantle is soon to go for her inaugural sail in the form of the 118ft long Juan Kouyoumdjian design Maiden Hong Kong belonging to Hong Kong-based industrialist Frank Pong.

Like Mari Cha IV this boat is another rules-be-damned ultimate speed machine. While Mari Cha IV is a giant with a canting keel, her design is relatively conservative in many areas, particular her rig. No such claims can be made of Maiden Hong Kong. Frank Pong's new craft although shorter in overall length sports not only a canting keel, but a sloop rig comprising a rotating wingmast that can be canted up to weather - in effect an enlarged version of a 60ft trimaran rig.

Although a massive boat, Maiden Hong Kong has had a much longer than normal gestation period. Designer Juan Kouyoumdjian first started working on her back in 2000 and construction of the boat began at DK Yachts in Malaysia in mid-2001.

"Frank is a very passionate and creative guy, so he made sure for this project, that he has always wanted to do, that every single detail was properly done," explains Kouyoumdjian. "Frank likes to be extremely involved with boats in the design and construction phase - I would say he almost co-designed this boat with me. That’s the main reason why we went to [build in] Malaysia. It’s a three hour flight from Hong Kong and he could get on his jet and fly down to spend a day in the boatyard." Construction was also held up for a year while a new build-team was brought in.

The design brief for Maiden Hong Kong was to create a boat in the 100+ft range capable of breaking monohull ocean records and race records. It is not anticipated that the boat will attempt a round the world record.

The design itself went through different stages and Kouyoumdjian says that ironically what they ended up with was close to the design his team originally conceived. "We started with an initial concept and then we simplified it quite a bit, mostly with the canting keel that wasn’t canting and the mast that wasn't rotating and canting either. So we started designing that boat and just before we went into construction we kept on coming back to the original concept. So it was like a circle, but through that circle we kept refining it as well. Obviously the more you get into the construction of the boat, the more you get into the details and refinements. So in fact it was a good process to go through."

The main issue with designing any ultimate speed sailing boat, be it monohull or multihull, is how long to build it? Kouyoumdjian says the main constraint was the power of the rig and trying to avoid letting it get so big that only fully custom-built (and therefore heavy) gear could handle it. "We did end up getting some custom winches, the blocks and some hardware, but it was only small customisations of existing gear. We didn't reinvent the wheel which is key to these projects otherwise you get into huge expense and time."

This is the same approach designers of all the latest generation supermaxis have taken yet while their number crunching has produced boats of 90-100ft LOA, Kouyoumdjian has managed to squeeze out a 118 footer ( Mari Cha IV is longer by virtue of her schooner rig). The key in fact has not been overall length, but displacement. While 90-100ft maxis such as Genuine Risk, Bols, Alfa Romeo, Skandia and Konica Minolta (ex- Zana) are all in the 21-26 tonne range depending upon whether or not they are trying to sneak inside the limits for the Rolex Sydney-Hobart race, Maiden Hong Kong has been weighed in at 28 tonnes. "There is a clear trade off of not going very big. There comes a point over 125-130ft where you are actually increasing the loads and the complexity of the yacht without increasing the speed. So it is all negatives after that."

To achieve this weight Kouyoumdjian says the concept of Maiden Hong Kong was to come up "with a boat that was like a car with the engine and wheels with the smallest possible chassis in between" - effectively rig and keel with the minimum amount of hull. "If you could avoid having a hull you just wouldn’t do it. So we were trying to push that concept as far as we could with a 120 footer within the reasonable limits of a crew that has to go offshore."

Unlike Open 60s which in addition to their canting keels achieve stability through having hulls with substantial volume (due to the IMOCA 10 degree inclination rule), free from this rule the canting keel on Maiden Hong Kong plays a much greater part in keeping the boat upright.

"When you get to these kind of sizes, with form stability you start paying a hell of a lot in drag," says Kouyoumdjian. "The best way of creating stability is of course through floatation of form stability but then you go into a trimaran or a catamaran. If you stay with a monohull, then the best thing to have is weight on the bulb."

However the problem with making the keel larger is that this too creates drag, particularly when with the keel canted the bulb is travelling through the water at 20+ knot speeds close to the surface. Thus Kouyoumdjian investigated ways of making the bulb heavier without increasing its size. With no class constraints it would have been possible to create a bulb made of gold or packed with spent uranium, were they not ridiculously expensive or almost impossible to obtain. In the end they opted for a bulb made of tungsten with a density of 18.2 tonnes/cubic metre, compared to lead at a mere 11.25 (or gold at 19.3 or platinium at 21.4).

While the bulb is tungsten, the keel fin is equally exotic, made of a particularly superior grade of steel called 15-5PH, normally used exclusively in military aircraft. "We waited for one year to get the raw material," says Kouyoumdjian. "You need special permission to use this material and this keel was made around the time of 9/11 so there were a lot of faxes going around..."

With the steel obtained they then had to find a company with suitable expertise to construct a keel fin from it. Fortunately during his time at Prada Kouyoumdjian had come into contact with Piero Refraschini in Milan, who normally works exclusively for Ferrari, but had made all the complex composite and metal pieces such as the tank test models for the Italian AC team.

Kouyoumdjian takes up the story: "When we got the steel, it took about three months to machine and then they had to do a very special heat treatment on it, because it had to be in stainless steel, or as stainless as we could make it. So in order to ensure that it had good mechanical properties you have to put it through heat treatments. When you heat a 6m long piece, it has to done in an oil bath and there are very few places which can do a piece that size and when you find one they are so busy you have to get in a queue. So there were lots of satellites projects like this. But in the end it was really nicely done."

With a draft of 6m, it was going to be hard to get Maiden Hong Kong in and out most harbours, so Kouyoumdjian and his team set about conceiving a mechanism for the keel that would allow it to not only cant by up to 35 degrees, but would allow it to lift, reducing draft to around 4.2m. To achieve this they worked closely with hydraulic ram specialists Cariboni in Italy.

"It was quite complex because you are canting a keel with an 11 tonne bulb on a 6m fin and you are asking it to be strong enough to work offshore but also to lift it when you are going into harbour. So it is a nice piece of engineering," says Kouyoumdjian.

To lift the keel it has to be centred. This is monitored by electronic sensors and then a housing drops down and grabs the keel, lifting it up. The minimum draft was limited by the height of the deck.

While Mari Cha IV has a single giant Cariboni ram to cant the keel, Maiden Hong Kong has two for security. Kouyoumdjian points out that the keel mechanism was designed some while ago when such systems were a lot less tried and tested on maxis.

But there is more on the keel... The design team rightly assumed that the keel striking a submerged object was a case of not 'if' but 'when' and as a result they have been at pains to protect what is one of the world's most expensive keels as best they could. The bulb itself has a shock absorber in its nose and there is an additional safety mechanism in it so that if it grounds a giant fuse breaks within the bulb and the bulb then pivots up or down around the end of the foil on a substantial central pin. This compresses some high density rubber pushing the bulb more or less back into place to within +/- 0.5 degrees.

In addition to this there is another safety mechanism in the foil. "Firstly the nose of the fin takes some absorption," says Kouyoumdjian. "Then the top of the trailing edge is designed to collapse on itself a little bit. All this is very theoretical and very difficult to calculate. So I guess we won’t know until we hit something. But the chances of hitting something are pretty high and it makes sense to have these systems."

All these safeguards are designed to prevent the energy from a grounding or a collision being taken by the keel, the complex canting/lifting mechanism and the internal structure. Their engineering must have taken an eternity.

Due to its narrow waterline beam Maiden Hong Kong has a single rudder, but instead of having twin asymmetric boards like most Open 60s, the configuration we imagine will also be used on the new Volvo Ocean 70s, the boat has a single fixed foil around 2.5m deep located just 2m back from the bow. Around 50% of this foil is a trim tab.

Kouyoumdjian explains this appendage: "The idea was to have a forward foil because the speed this boat is going to be doing, a big part of the hydrodynamic resistance is created by the wave making of the hull and the interaction of the appendages. So we thought about having a forward foil that not only allows you to control the boat but minimise the wave making. It can’t be a rudder like you have on the back of the boat, because you can’t put it where you should put it because the boat gets so thin at the front, you can’t fit in a bearing as there is not enough room. And if you put it further back like the CBTF boats the rudder doesn't do what it is supposed to do because you have to put it so far back in the boat where it is counteracting the hollow part of the wave."

In addition to having a foil forward near the bow Kouyoumdjian says that to load the foil properly it is also necessary to minimise the yawing moment of the rig and this is where the 60ft trimaran-style canting rig comes into play. "In order to load the foil you have to have the balance and if you don’t have a canting mast you have to put the mast a hell of a long way forward on the boat otherwise you can’t trim the mainsail. So it all works together."

Obviously the forward foil is as prone to possible impact as much as the keel is, thus it has been designed to sheer off cleanly along with the shaft that operates the trim tab.

Tomorrow we look at the unusual hull and rig configuration of Maiden Hong Kong