The mini Ericsson rocket ship

We look at the new Juan K designed K650 sportboat

Ericsson 4 has just won the Volvo Ocean Race, but for those looking for a piece of Juan K action in something a little more modest, Yum Boats in Honfleur may have just the ticket.

Launched last summer, the K650 is rather confusingly nothing to do with K-Challenge, who some years back launched the K-One Design 33, also designed by Juan Kouyoumdjian. The K in K650 stands for either Kouyoumdjian or Karver, the French hardware manufacturer who conceived this exciting new sports boat.

The 650 element of the name is also a little misleading as although it is the same length, the boat is not a Mini, but a closer relation to the sportsboats such as the Open 7.50 and Open 6.50, familiar to sailors in Brittany, but which have generally gone little further.

The most popular of these French sportsboats is the Groupe Finot designed Open 7.50, made by JPS Production in La Trinite-sur-Mer that is now around 10 years old. In Brittany, many of the sailing elite there race these - most notably Marc Guillemot, skipper of the Open 60 Safran, who was competing aboard his last Saturday in the Bol d’Or Mirabaud with Dominique Wavre and Michelle Paret. JPS also produce the Mach 6.5, which is similar in concept to the K650, but designed by double Mini Transat winner/naval architect Seb Magnen and not Juan K. Some years ago a Finot-designed Open 650 was also produced, but in small numbers as it was an all-carbon boat and somewhat expensive for its length.

“They are really nicely built boats, very efficient, very fast, but the problem is that they have never been outside of La Trinite,” states Karver’s own Mini turned Class 40 sailor, Tanguy de Lamotte. “They are not known in England or Spain, etc. We thought it was time to make a sportsboat that wouldn’t just be French, because the French know the Open 7.50 and they like racing those boats, but there are only a few around. So we decided to go with Juan and try and make it a world-wide class.” Within the Karver office he says there are several sailors with experience of boats of this size and this combined with their company’s expansion internationally is what prompted them to create this high performance sportsboat.

De Lamotte knows the UK well having studied naval architect in Southampton and also for a while was shore crew for Ellen MacArthur’s Kingfisher Open 60 campaign. “People who are racing J/80s or SB3s - they are having a lot of fun on the water because there are so many people, but the boat itself is not so exciting, it is an old design and it is time to move on.”

Viewing the K650 outside the Societe Nautique de Geneve last Friday, it is a highly innovative little boat. The Juan K hull shape is like a mini Ericsson with a powerful bow section, slab sides and pronounced chines leading to a narrow waterline. In addition she has a giant 2.3m draft (a Melges 24 for example draws 1.52m), but significantly the keel doesn’t have a bulb; it is merely a foil packed with lead. Long and with a high aspect ratio, the foil is designed to provide optimum lift to windward.

Rather than going up and down, as the keel does on most other sportsboats for trailing, instead the K650’s operates like a centreboard. However it doesn't disappear into the hull, merely folds up against it. In its ‘up’ position its bottom is just 450mm proud of the hull.

Keel/centreboard movement is operated via what appears to be the bottom of a roller furler unit from two lines on deck. This furling drum is down below on the front end of the keel and powers a worm drive that pulls or pushes a lug on the back of the keel head forwards, the keel rotating about its aft side at the hull exit obviously (ok, it will be easier to understand this by looking at the illustration at the bottom of this page). As a result the keel can be brought into it up position quickly and easily from on deck. In addition this mechanism is fitted with a fuse, so that in the event of a grounding this breaks allowing the keel to kick up partially.

Unusual, outside of France at least, is that the boat has twin rudders, Ericsson-stylee, despite being a pint-sized VO70 and not having the massive beam to length ratio of her big brother. The reasoning is that when the boat is heeled one rudder would not work as efficiently as two and according to Tanguy de LaMotte, this provides much better rudder control, not to mention efficiency, hooning downwind at speed. Since the prototype was launched last summer, the rudder blades have reduced in size. Cunningly, the tiller bars connect to the central tiller in such a way that the outer rudder, when turning, always steers more than the inner. This provides more manoeuvrability. The transom-hung rudders are not kick-up as you might expect, but are fitted to the transom with conventional gudgeons and pintles.

The rig is also unconventional by sportsboat standards. Not only does it feature a beautiful carbon wing mast, built by Eon Composites in Vannes, 10.5m off the deck and capable of rotating by 90degs in either direction, but the sail plan is a move away from the typical large main, small jib set-ups we’ve seen over the last few years: On the K650 the main is 23sqm while the jib is 18sqm and is overlapping.

“The jib is so massive that sometimes we have to open the slot a lot, so we can change it [the sheeting angle] from 7 to 12 degrees, or something like that. It is quite strange – you think your big jib would be very difficult to carry in a lot of breeze, but opening the slot it just really drives the boat through the waves,” says de LaMotte. “The boat is quite heavy, but its centre of gravity is quite low, so it doesn’t really pitch in the waves. It has a lot of drive for such a small boat. It feels like a 7.50, a bigger boat.”

Impressively in the cockpit there are no winches, and instead there is far greater use of purchase systems, again something borrowed from the Volvo boats. Thus the jib sheets are 2:1 and terminate in an additional 4:1 purchase, a fine tune that the crew can use for trimming from the weather rail. Kites are trimmed, with the sheet passing through a ratchet block.

Compared to a conventional monohull arrangement, the rig is stayed much more like a multihull with a single set of diamonds hanging off a single set of carbon spreaders and there is no backstay and in fact no fixed forestay, which could make life exciting at times. Instead the shrouds are a long way aft and the jib furler has a Kevlar cable running up it, tensioned via a 16:1 purchase on the mast. This allows very rapid tuning of the forestay tension/mast rake says de Lamotte.

This being a Karver boat, the mainsail halyard is on a lock, although this is a simple metal plate at the masthead on to which hooks a ring in the head of the main.

We put it to De Lamotte that instead of the shrouds being locked off on chain plates they could have made the shrouds adjustable while sailing too, the result being a rig like the original on the Pindar Open 60. “We thought about that, but it was a bit too tricky to have fair racing, because if you put too many things on people get it wrong,” he says.

The K650 of course comes with a retractible 2m long bowsprit operated from the bowsprit, but this has the additional feature of it being able to be cranking up to weather by around 18deg, allowing deeper angles to be sailed downwind. The whole deal is operated from the mast step by just three lines with a 3:1 purchase on the canting line to enable it to be adjusted with the kite up and pulling.

The K650 is built by Pom Green’s outfit, CMI in Thailand where de Lamotte’s Rogers-designed Class 40 was manufactured. This is hull number 5, with number six shortly to arrive in the USA.

The hull is built in GRP but using infusion and vinylester resin. The deck has a 15mm foam core, while in the hull it is 3mm Soric foam that has a hexagonal pattern, giving it that more expensive ‘Nomex honeycomb’ look. The limited space down below is not really for anything other than stowage, however all the mouldings, including the bulkheads and the internal liner are made from female moulds.

In Europe the price of the boat is 38,000 Euros ex tax and sails (around 3-4,000 Euros) and trailer (around 2,000 Euros). There are bits of the boat we saw that could be more Gucci such as the conventional metal chainplates, GRP rather than carbon/epoxy hull construction, but then the boat would certainly be more expensive.

The boat has already clocked some impressive speed - recording 19.2 knots on the log under kite and a slightly more scary 16.9 under jib alone beneath a black cloud, de LaMotte recalls. Upwind she typically does 6.5 knots. “It is faster than a Mini. It is lighter and it is not so wide. And we have a really big jib. On the Mini I didn’t carry a jib this big and I had the biggest jib in the fleet!”

So the K650 - small, but perfectly formed and a piece of the latest thinking from the designer of the winning boats from the last two Volvo Ocean Races. All that is needed to complete the picture is a lifesize inflatable Torben Grael to go on the helm.

We saw the boat last weekend at the Bol d’Or Mirabaud where she won her class, despite not completing the course in the light winds. Tomorrow watch out for her as she will be competing in the JPMorgan Asset Management Round the Island Race.



More photos on the following pages...