Above left to right: Ultimate79 (trackdays only); the Maxi79 (turboed labour-intensive Maxi72); the High Performance79 – ticking all the boxes? It makes sense that if you are to compete against the world’s most refined 72-footers – the Maxi72s – then having a bit of extra length to get ahead of them on the first beat may give you enough of an edge plus enough extra hull volume to carry a modest lightweight interior. Jethou (ex-Rán) helped launch the Maxi72s but did the fleet no favours when later lengthened out of class in an effort to be more competitive at Maxi events. Ten years after helping create a new fleet the loss of a good boat was not helpful at all
case 24.08m or 79ft – in other words a maximum-sized Mini Maxi. To make our comparison wide enough
to help us with our starter questions we wanted to explore three different set-ups. Two to cover the corners in terms of what we think are reasonably hard-pushed concepts of pure racers and one that allows some use off the racecourse as a daysailer or weekender. So the different concepts we chose we called Maxi79, High Performance79 and Ultimate79. The Maxi79 is set up in the style of the
Maxi72s. However, with the Maxi72s already hitting the ‘natural’ limit for a fixed single-keel boat with a draft of 5.4m in terms of finding berths in typical venues of
interest, the Maxi79 concept
due to this slightly toned-down build method but the main aim is to offer a more reasonable price. The High Performance79 is equipped
with a 4.5m maximum-draft canting keel, with a maximum cant angle of 40°. A higher-cant angle is a possibility but it is directly related to both an increase in costs and complexity with increased pressure on interior space. The other appendages are a single rudder aft and a centreline board with a trim tab forward (a similar appendage configuration to the highly successful Cookson 50 IRC design). In terms of sail area and stability the
is
equipped with a lifting keel. In the raised position the draft would be 4.5m and in the lowered position 6.3m. The extra length also dramatically increases the potential number of berths compared to a Maxi72. The boat is sailed with the keel in the lowered position – only being lifted in sheltered areas or to access your berth. The Maxi79 concept is – as the
Maxi72 – completely stripped out, solely used for racing, with a deep single rudder. We will sail the boat fully crewed as per the IRC limit with 24 crew. The winches and hydraulics are manually driven using a linked five-pedestal set-up. The High Performance79 is the concept
we really want to test against the other two, with some interior for daysailing and weekend cruising, but apart from that still with a big focus on racing. To keep costs under control it is to be built using carbon Sprint laminates with foam core in the slamming areas and in other areas of tight curvature. Nomex core would be used in the deck plus other flat areas in the hull and structures. There is a little weight hit
High Performance79 is about the same as the Maxi79 concept. However, all running rigging is managed hydraulically. The IRC crew number is set to 14. The
reason for the reduced crew is to keep costs and logistics under control – with manual winches replaced by hydraulics, for the extra crew there would also be little to do other than hike. The Ultimate79 concept goes as far as
you could push it technically. Main com- ponent is a Mini 6.50-style telescopic cant- ing keel allowing for a minimum draft of 4.5m and a sailing draft of 6.3m. Cant angle chosen for our comparisons is 50°. Not the most extreme but quite a step compared to the ‘standard’ cant angle of the High Performance79. The hull is made from pre-preg carbon with Kevlar core in all areas. The other appendages are deep single rudder aft and two asymmetrical daggerboards port and starboard. Run- ning rigging is again operated by hydraulic winches with the crew dropped to 14. This design is much lighter than the
other two with higher stability and bigger sail area. The Ultimate79 follows the concept of the big line-honours candidates we have seen recently (such as Rambler 88
and Comanche) but taking advantage of the latest knowledge and technology. For all three we ran full CFD studies
and generated VPPs to compare. For sim- plicity we compared mainly up/downwind performance. Those are shown overleaf as real performance differences in terms of seconds/mile with true wind speed mea- sured at 10m; and corrected results in sec/mile also with true wind speed at 10m using IRC and ORCi rating. We also show a real performance com-
parison over a typical coastal course (with some additional reaching on top of the upwind and downwind VMG legs). Base- line in all comparisons is the Maxi79. We took it as our default because as a concept it is familiar to us as the Maxi72, with reg- ular appearances and successes at big races around the world. Scaling up the Maxi72 seemed the most reliable starting point. Real speed comparison shows a clear
advantage for the Ultimate79, as expected. It is the lightest concept with the biggest sail area; but especially in the light the delta is not as big as one might guess, although you cannot underestimate the effect of the added wetted surface area of the appendages combined with the wind - age increase produced by extra elements like raised daggerboards and a taller rig. The High Performance79 sits nicely in
the middle, being lighter than the Maxi79. In a coastal race the boats are quite simi- lar, the biggest difference being a slightly smaller delta in 8-10kt TWS of the Ulti- mate79 versus the Maxi79 but a bigger gain for the Ultimate79 above 12kt. The really interesting part is the com-
parison of the results on corrected time under IRC and ORCi. Here we see a clear indication that the extra speed of the Ulti- mate79 is not able to compensate for the huge rating hit she carries against the other
SEAHORSE 49
INGRID ABERY
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