by Jane Fossett and Naeve Rossini
WOOOT!! Let me give a huge shout-out for Naeve Rossini; She sent me her polar plots for a popular boat I’ve not had an opportunity to test, the RCJ-44 (a.k.a. “Orca Flotta’s favorite boat“).
The RCJ-44 is a large, sloop-rigged one design cruiser/ racer. It’s widely regarded as extremely fast and relatively easy to handle, making it a popular choice on the Big-Boat circuit.
The PHRF handicap results from April confirm the impression the RCJ-44 is super-speedy. If you look on the chart to the right, the blue numbers reveal the 2009 Handicaps for different boats tested in Madaket, while the green numbers show last year’s scores obtained on a series of different race courses. The RCJ-44 so far has a handicap of 1.29, which makes it nearly 40% faster on a standard lap than a Trudeau J-Class (handicap 0.93).
Excluding the ACC-2 (which uses a different wind system), the RCJ-44 is actually faster than all other large boats tested under PHRF except for the VOJ. That probably makes sense, since it’s also made by Wildwind. The RCJ-44’s speed is comparable to Surwidow Beaumont’s Dutch Barge (handicap 1.27) and just behind the venerable Tako 3.3 (1.31) (Happy Birthday Kanker!!!).
The graph below uses Naeve’s data to detail the RCJ-44’s performance. With a constant 5.0 m per second breeze, The boat’s maximum steady-state speed was determined for apparent wind angles between 10° and 180°. The blue line shown below reveals the boat’s performance with mainsail and jib. The red line, on the other hand, shows what happens when you swap the genniker as the headsail.
For comparison purposes, I’ve included a similar chart for the Trudeau J-Class right below the RCJ-44 data.
Using the jib, the RJC has a fairly broad performance curve that is largely flat between 60 and 90°. Between 35° and 125° the boat’s speed over ground (SOG) actually exceeds the real wind speed. It’s no wonder this boat is very popular; the wind algorithm is more forgiving than your Mom, and (grin) perhaps at times as unrealistic!
Luffed windward at 20° apparent, the boat makes minimal headway. However the moment the sails fill as it falls off to 30° the RCJ-44 springs to life, accelerating to an SOG just below true wind speed. This sudden, explosive upwind response is typical of camber airfoil dynamics as the sails take shape and turn into a ‘lift engine’ driving the boat forward. The same thing is true for the Trudeau J-Class, as shown below. In that case, though,The sails start to fill later, between 30°- 40°, generating a lift that results in an SOG that’s 75% of True Wind. The J-Class is hardly as kind or generous as the RCJ, but perhaps it’s more realistic. The J-Class offers a skipper a more pragmatic, hard-nosed, “Tough love” Big Boat option.
Of course, there’s another practical explanation of the upwind difference in the two boats: The J-Class is a remake of a legendary racing boat from the 1930s; one should hardly expect it to point as high, or sail as fast as a present-day high-performance yacht. The difference between the two boats is a bit surprising, however. (Newtonian physics is still the law now, as it was in the 1930’s, after all.)
Take a look at the red curves now for both boats. For the RJC, that curve shows the speed over ground for the RCJ-44 when flying a genniker. On upwind points of sail, the shape of that foresail is inefficient, and it does approximately 20% less well than a standard jib. However, between 100° – 110° the genniker suddenly kicks in and comes to life; there’s an easy25% boost in boat speed as the genniker fills. By 120° Apparent, using the genniker is a full 20% faster than relying on the jib alone, and that difference expands to over 80% on more extreme downwind points of sail. Once again, these numbers are somewhat exaggerated compared to real life, particularly considering the RL common use of oversized genoa jibs. A genniker or asymmetric spinnaker can be expected to provide a big downwind boost, but 80% only makes sense if you have divine intervention. Lindens haven’t quite reached that status yet.
Having said that, if you look at the red curve for the Trudeau J-Class in the second chart, it probably underestimates the spinnaker effect. The J-Class throws up a massive, symmetric spinnaker, and there is approximately a 20% boost in performance at 130° when compared to the jib alone. This performance enhancement widens progressively on further downwind points. Given the size of the spinnaker and the downwind physics of headsail performance as translated into second life, an initial boost of 10% when the chute inflates and a boat speed of 40% true wind at 170° apparent may actually well underestimate the spinnaker’s true potential. (In other words, that’s one big whopping sail! It should have a BIG whaopping effect, and the J-Class parachute may be underpowered!).
Please don’t take any of this as serious science, however; good grief. Both the 44 and the J-Class are wonderful, fun boats, and all the numbers discussed above are mostly intended to give sailors more fuel for their late-night arguments over sailing strategy and the creative explanations we all evolve for why we lost that last race… (grin).
Should you buy a 44? Is a J-Class better? I don’t know; Naeve doesn’t know either. They’re both highly detailed and well planned-out sailing vessels that reflect the skills of the artisans. Both boats stand in tribute to the wonders and challenge of sailing, in real life as they do here in second life.
As sailors we should all feel privileged to have options… both options… and so many more, as well.