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project for Marcelino Botin and co-designer Adolfo Carrau after two years refining AC62 foiling catamaran designs for Luna Rossa.

Under the water

Though above deck she is dramatically different from the Vrolijk and Mills designs, below the waterline Cannonball is more conformist. Carrau explains: “We could have come up with something completely different, but we felt it was not smart to take a big risk. Instead we’ve tried to optimise what was already out there.”

So, waterline beam remains similar to the competition and, even if she is designed as an ‘inshore’ Maxi 72 with less of a requirement for reaching, she doesn’t seem slow on this point of sail, largely thanks to her light displacement, which is around 200-300kg less than the competition.

Keel fins, bulbs, displacement, stability and how it all might affect rating have been major considerations with the design. Driven to where the designers feel is the sweet spot, Maxi 72 displacements are now in the 16.2-16.4 tonne region and therefore relatively heavy – by comparison more robust VO70s, complete with canting keels, displace 14 tonnes.

Designer Adolfo Carrau says: “We’re probably four or five generations in with the Maxi 72s, so when we started the design the fleet was already converging at an optimum displacement. For example, Rán 2 was around two tons heavier when she was launched and gradually she became lighter, deeper on the fin, with more sail area and more powered up.”

Recently all the Maxi 72s have altered their keel fins. Teams had been putting lead inside the fins until IRC began rating this separately, causing many teams to move to solid steel fins of a similar weight. “And in the next couple of years I think the penalty’s going to get higher, so that’s what triggered most teams to start work on new fin designs,” explains Carrau.

In Cannonball’s case, she has a relatively small bulb and a solid steel fin. “From day one we were very conscious of having a good balance between how you arrive at your target righting moments: a bit from the hull, from the bulb, and the equipment,” says Carrau.

Pumped up

There was much outcry during the last America’s Cup about grinders/cyclists pumping hydraulic fluid, but in the Maxi 72 class they have been doing this for years. Thanks to the loads involved, there is a substantial hydraulic system on board, with rams controlling everything from forestay to outhaul, vang and deflectors, although there are also many rope systems for items such as tack lines – of these surprisingly only the code zero’s is on a purchase aboard

Photo: Rolex/Carlo Borlenghi

Cannonball. However, on Maxi 72s the pedestal winches can, either individually or in unison, operate not just the rotary pump for the hydraulics, but all or any of the winches simultaneously.

All Cannonball’s hydraulics are by Cariboni while her four custom pedestals are from stayinphase – gear from both companies having benefited greatly from development done for the 35th America’s Cup. These are accompanied by load cells throughout the boat, including appendages, so the team’s engineers can get an ongoing picture of the structure, deflections, etc.

The three-spreader carbon fibre rig is from Southern Spars with carbon fibre EC6 shrouds and a Future Fibres carbon-PBO forestay. All the sails are on Southern halyard locks. Masthead runners are fitted not only with deflectors,

Left: heavily chamfered hull to deck join around the foredeck is structurally stronger, saves weight and reduces windage, but makes for a narrower foredeck. Bottom left: the foredeck hatch is offset to port. Below: tapered bowsprit slopes downward to maximise sail area, while the curved top to the bow further reduces weight and windage

Cockpit is cleverly designed in a roughly triangular shape. The primaries are positioned inboard to allow a direct run aft for the jib sheets. Immediately abaft this the cockpit edge turns outboard, ensuring the weight of crew sitting inboard is as far up to weather as possible. Note the custom stayinphase pedestals, which, like the Cariboni hydraulic system has benefited from development for the 35th America’s Cup. The side decks are impressively clear, with the ropes piped below deck

Photos: James Boyd/ 32 ||||||||| | ||||||||| | ||||||||| | ||||||||| | ||||||||| | ||||||||| | ||||||||| | ||||||||| | ||||||||| | ||||||||| |

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