by Jane Fossett and Naeve Rossini
This weekend Corry Kamachi released the new WildWind Open 60 sailboat, the JMO-60.
So what’s an “Open 60?”
The new JMO-60 is a high-performance ocean racer, inspired by the RL Open 60 Class boats. The International Monohull Open Class Association (IMOCA) sets the specs for the Open 60 (“60″ refers to it’s 60 ft length) describing it as “The most successful ocean racing class” currently on the water. IMOCA also sets rules for competiitions and helps organize many high-profile, long-distance ocean races world-wide. These are the cutting edge thoroughbreds of extreme sailing; lightening fast, carbon-fiber tough, and an inspiration to behold. This boat belongs in SL.
And Corry got it right! Here’s a diagram of the RL Open 60, above.Frankly, I like the SL version more 🙂 !!
The JMO-60’s form faithfully follows the speed-craving sleek shape of the Open 60 wedge, down to the details of its swing bulb keel, its carbon-fiber spars, and even it’s satellite communications dome (I assume that’s so a global skipper can stay logged in to SL while rounding Cape Horn). The hull comes in two flavors: one is stripped down to the essentials needed for 100+ region ocean races and arduous sim crossings. The other is more nuanced, prim-laden and contemplative. It’s the fancy version for those late nights when your ocean passage is done, and you decide to grab a mooring at some tropical marina in an exotic estate along the race route… and perhaps invite the natives aboard.
True to RL form, however, I admit the JMO-60’s cabin is pretty spare. You’ll find inside an uncomfortable bench to lie on and a compact nav station, just like the RL racer’s accommodations. Sorry ( 🙂 ): The Open 60 Class specifications don’t include options for a hot tub or sexgen animations. If you want those things, you can (a) Buy another boat, or (b) Wait till the race is over.
Your decision will depend, I suspect, on how much you really want to win that next SL Global Challenge Race…
Sailing the JMO-60
The JMO-60 comes with a blizzard of adjustable settings and sailing options that allow the skipper to customize the vessel to their preferences, and it shares many features in common with two other WildWind ocean racers, the larger VOJ-70 (modeled after the Volvo VOR-70 standard) and the small but speedy RCJ-44 that was previously discussed in these pages. I’ve posted copieds of the Information Notecards that come with the boat to a webpage here, for sailors’ ease of reference.
JMO-60 will carry a skipper and two crew members. The skipper is responsible for all the sailing, and the helm cannot be shared (or ‘loaned to’) your sailing friends. Sometimes the crew is there just to keep you company, I guess; can’t complain about that!
This is a boat that will keep the skipper busy, too! It comes with a standard mainsail and three different headsails that each optimize performance under different points of sail. There’s a working jib, a Genoa jib (for lighter air) and a Genniker for a downwind boost. The boat lacks a true spinnaker, but frankly on an ocean racer where only one skipper is in charge of the helm and all sails, putting up a parachute in RL sound pretty suicidal. Although the RL Open 60 spec does include a spinnaker, the IMOCA strongly advocates a limited set of racing sails, for safety as well as design compatibility. Believe me, there are so many racing adjustable features on the SL version of the boat that three headsails are more than enough!
Like other boats in the WildWind line, JMO-60 has a swing keel and the rigging can be adjusted to optimize acceleration, speed, or turning ability to suit the particular race conditions. OH! Did I mention you can reef the masinsail too? 🙂
JMO-60 comes with an unassuming ‘button HUD’ that attaches to the upper left corner of the viewer and lies along the left side of the screen. Most racers will probably want to switch to chat commands however, since they are generally more reliable under lag conditions in a crowded fleet. A simple, numerical “info HUD display” superimposes all the sail data you would ever need right in the middle of your screen, so you’ll never miss that wind change…
The JMO-60 just hit the water a couple days ago, and there are so many features to this boat it will take several weeks to sort everything out ( actually, the way I do stuff, it could take me years!). Given the excitement about the boat, however, I thought it would be fun to report some basic performance data and compare it to similar boats in the fleet.
The graph below charts the Speed Over Ground (SOG) for the JMO-60 at different apparent wind angles. For all these initial tests a standard, slow wind speed of 5.0 m/s was used, and all the boat’s adjustable parameters were held constant. The blue line below is the important one; it shows the steady-state boat speed you can expect when flying the appropriate headsails (Genoa below 110°, Genniker above) with optimal sheeting.
The results show that the JMO-60 uses a very generous and powerful wind force algorithm to drive the boat. The sloop begins to make effective headway well below 30° apparent, and there’s a steep ramp-up in performance as the boat falls off to a close reach; at 40° apparent, the JMO-60 is already traveling at 90% of real wind. Before it reaches 50°, the actual boat speed exceeds real wind speed (I guess we might call that ‘warp drive’), and the boat never looks back until it’s almost on a dead run. Peak performance appears to be a Broad Reach point-of-sail, where the boat hits a miraculous 125% of real wind, and even with a downwind heading of 180° the JMO-60 will pump out an impressive 80% of real.
Woots! No need for a spinnaker if you can generate those numbers with the Gen!!!
As you can see below, theBlue curve has two small humps that correspond to the the peak performance of the Genoa and the Genniker, respectively. The headsails are nicely matched, and there’s a smooth transition when you drop one and raise the other.
Just for comparison, below I included two more curves. The purple response curve shows what happens if you make a mistake and use the wrong headsail (the working jib); with a 5.o m/s light breeze, you should use the Genoa.
As the purple line shows, on upwind points of sail if you mistakenly use the working jib you get paid back with a 20% power loss compared to the bigger Genoa sail. No surprise though, when you hit 110° and flip to the Genniker, the downwind performance overlaps the blue curve for that same headsail.
Just to take it one step further, I also charted the performance curve for the RCJ-44 with no jib; that’s shown in red below. On upwind points of sail, an RCJ-44 without a jib is just as fast as the JMO-60 flying the aforementioned wrong jib!
I know that may sound confusing… but what’s my point here?? IT’S SIMPLE: Make sure you use the right headsail!!
Actually, I have a more important point to make here. The chart below shows that over 110°, travelling downwind with the Genniker up, the JMO-60 and RCJ-44 are virtually identical.
What about upwind, though? Which boat is faster, anyway, an RCJ or a JMO?
The chart below answers that questionI think… at least for wind speed = 5.0m/s.
The new chart is identical to the one above, but I’ve added one more curve. The light blue line below shows the performance response of the RCJ-44 using the correct sail plan and optimal sheeting. As I just mentioned above, on downwind points over 110° the RCJ-44 and the JMO-60 turn out to be identical. But look what happens when the boats turn windward! Flying its jib, the RCJ-44 is easily 15- 20% faster than the JMO-60 on all points of sail from 30-100° wind apparent. I hi-lited that difference in yellow below.
As any sailor knows, however, this result is only for one unusual wind speed (5.0m/s), and it’s important to see how the curves shift with changing parameters. Just as important, the JMO-60 has a wider list of adjustable options than the RCJ-44. It may well prove that a seasoned skipper can play those features to advantage racing, responding better to whatever new conditions arise.
Polar plots are a standard way to show the kind of performance data I’ve detailed above. This display format makes it easy to get a quick visual impression of a vessel’s performance spectrum across all apparent wind headings. The polar plot below shows performance data from 0-180°apparent wind for three different boats. The JMO-60 is shown in red on the right side of the figure. The RJC-44 is shown in blue on the left, and the 44’s upwind performance advantage is reflected by a noticeable bulge of the blue curve compared to the red.
But now take a look at the third boat I’ve added (in Green): The Trudeau J-Class. It’s polar plot is radically different from the other two, even though it’s also a meticulously detailed, noble ocean racer. So who is right? What’s the correct sail engine performance?
Actually that’s an easy answer; just ask any ocean sailor in SL 🙂 .
The WildWind JMO-60 models a present day ultra hi-tech race class that intentionally hovers on the bleeding edge of extreme ocean racing. The J-Class on the other hand reaches back 80 years to the ‘extreme’ Cup boats that made history competing in the 1930s.
Yup, the curves above for these boats are different; they should be…
But the attitude is the same, and the desire is the same: to bring Real Boats in to SL’s 3D world and push the limits hard everywhere… with apparent wind, shadowing, reefing, headsail switches, keel adjustment, rig tuning, crew hiking… and all else a sailor might rely on to coax a frail boat to rise and fly before the fleet...
Anybody have a problem with that?
If so, leave me a message;
I’m off to wiggling my keel while sailing my JMO.