Here we go! The most recent PHRF Handicaps, including a few new boats, and some tighter numbers!
In the last few weeks, despite some pretty terrible grid-crossing conditions, a group of stalwart skippers added more hotlaps scores to the PHRF database. Thanks to:
Gemma Vuckovic, Francois Jacques, Carmen Foden, joro Aya, Garrick Diesel, Justbent Clarity, Heidi Stiglitz, Angus Moonwall, Dunan Wilder, Chaos Mandelbrot, Cory Copeland, LDeWell Hawker, Oliphant Ming, Julia Ceres, Liv Leigh, Triton Sands, Hal Burnstein, Blackbird Latte, Argus Farman, Vin Mariani, Rodman Mapholisto, Alain Gloster, Jane Fossett, nobuko Criss, Allie Tomsen, Angus Moonwall, Bunnie Mills, CS Price, Emme Eales, Jehan Jameson, Liv Leigh, Naeve Rossini, Nomad Zamani, Reven Fhang, Quirky Torok, Isis Rexie, Everest Piek, Arrekusu Muromachi and Masahisa Greenwood.
Here’s the new table, and it follows the same format and conventions as previous ones. (Note: I updated the tables below on August 12 based on Lance’s suggestion to post alphabetical and performance-sorted versions. Bosth are shown below. I’ve also color-coded the boat names, based on the wind engine.)
Compared to the last update in early June, the numbers are more consistent and seem to be falling in line with the results from 2008 PHRF (where available). Thanks to Live Leigh, we’ve added a new boat too, the Catfish 33 catamaran. We need to get numbers from other skippers on it, but my guess is Liv’s PHRF lap probably hit it on the nose for this boat: Her lap came in with a perfect, corrected Handicap score of of 1.00 for the new fishy cat!
The JMO-60 is also new on the PHRF list, coming in with an average Madaket lap time of 8:55 and an adjusted handicap of 1.32. This makes the JMO-60 comparable racing to the RCJ-44, as predicted by the very similar polar plot results for the two boats. All three WildWind boats so far tested (RCJ-44, JMO-60, and VOJ-70) prove extremely fast, particularly compared to other boats powered by ‘apparent wind’ tested at Madaket (such as the Shelly, Catfish, and Trudeau Twenty family).
The Wildwind’s strong showing on lap testing appears to be partly due to the way it handles Apparent Wind.
There are three different kinds of wind most sailors think about, whether they sail in Real Life or in Second Life.
The first is called “True wind.” True wind is the force generated by the movement of air against a stationary object, such as a boat tied to a dock. It’s the same wind felt by any person standing on the dock… or by the dock itself. In the diagram below, “A” shows an example of a stationary boat, and the arrow represents a 5.0 m/s True wind. Wind is a vector with direction as well as magnitude. In this case, the wind direction is 90 degrees off the boat’s bow.
Kanker Greenacre’s Flying Tako uses a “real wind” algorithm to power the boat. Based on Kankers original scripts, several other highly popular boats are also powered by real wind, including the ACA 33, the Tetra 35, the Trucordia Yawl and the Trudeau Larinda.
Most boats move, however. That movement generates a second type of wind called a “headwind.” In example “B” below, let’s assume the wind dies and our boat’s becalmed, so there’s no True Wind. The Skipper turns on the engine and soon the boat’s traveling at 5.0 m/s. Even though there is no true wind, all the sailors onboard all feel a breeze on their face that’s generated by the boat’s forward movement through the air. That “headwind” is always coming from the bow and is always equal and opposite to the boat’s speed over ground. In “B” below, the boat sees a headwind of 5.0 m/s from 0.0 degrees.
Now let’s assume the true wind starts to blow again, and the crew puts the sails up! The boat moving through the water now sees the combination of the true wind plus the headwind, as shown in “C” above. Adding the two wind vectors together gives you the Apparent Wind. This is important. since Apparent Wind is the wind a boat sees; it’s what actually powers the boat. Most recent boats in SL are based on an apparent wind sail engine; they represent a major advance and a closer emulation of real-life sailing. Apparent wind was introduced in SLSailing by Owen Oyen’s ACC, and it is now commonly found in recent Trudeau boats (beginning with Trudeau Twenty), Caf Binder’s Jangars, and Mothgirl Dibou’s Fizz 3. It’s even available in the Shelly and Leetle Cat teaching boats for new sailors.
The use of apparent wind means that as an SL sailboat accelerates upwind, the contribution of the headwind increases. The wind angle therefore shifts toward the bow, and a skipper often needs to steer away from the wind to keep the boat from stalling. For example, in order for a J-Class moving upwind to sail a course with an apparent wind angle of 40°, the boat’s angle with the real wind needs actually to be over 60° to cancel out the headwind.
This makes SL sailing a little more challenging, but far more realistic.
Three SL Wind engines
The reason I’m bringing it up in this context is my concern that the PHRF scores listed above may only be accurate within boats that use the same basic wind power algorithm. I’m quite sure that “Real Wind boats” can use the above handicaps on nearly every racecourse in SL. We’ve officially tested seven courses, and I have unofficially confirmed it on twice that many (grin, try it yourself!). I’m also “pretty sure” the handicaps work for all the “apparent wind” boats as a group. I’m far less certain it works as a comparison of “Takos ad RCJ-44s” for example, even though the two boat classes have similar handicaps.
OK OK, the real reason I’m bringing this up has to do with WildWind boats. According to the notecards that accompany the JMO-60 and RCJ-44, WildWind boats are powered by an “apparent wind” algorithm. The boats come with a numerical HUD that reports values for the real wind and the apparent wind. However, if you get out your pencil and take the HUD values for real wind and boat speed and calculate apparent wind yourself, you’ll find out that WildWind boats underestimate the apparent wind effects to a large degree. In the figure below, the 5.0m/s true wind is coming from 0° and the boat is traveling on a heading of 60° to that true wind. The boat’s speed is 4.9 m/s. The calculated apparent wind should be 8.6m/s at an angle of 30.2° [shown in yellow], but the WildWind algorithm reports it as 47° and 7.64m/s. That miscalculation makes WildWind boats much easier to handle and results in a faster lap time compared to boats that use “RL physics.”
In the figure above I state this is an “apparent wind error.” I apologize, this is my mistake; it’s not an ‘error.’ As I stated above, Kanker Greenacre himself used Real Wind to power the Tako. Kanker’s a real sailor and knew the difference between real and apparent. He intentionally simplified the algorithm to reduce script calculations and make sailing easier for a generation of non-sailors in Second Life. I believe WildWind adjusted the apparent wind calculations to make their boats very fast and a lot of fun; I think the ‘adjustment’ in apparent wind calculation was intentional, not any ‘error.’ My issue here is just to point out that the boats are not driven by “apparent wind” but something unique, a compromise, and to comment that the PHRF scores for WildWind boats may therefore not work when applied to other boats in the list. I actually need to do more statistics to answer that question though, and I try to avoid doing statistics in August (grin).
Let me leave no doubt, however: I think WildWind boats are very fast, very pretty, and a great deal of fun. They also introduce a new algorithm, one that is a compromise between real and apparent wind. That adjustment makes the boats easy to sail, and in fact makes them pretty exciting. Since they don’t use apparent wind, perhaps the boats shouldn’t be considered a serious emulation of real sailing however. I don’t know; maybe that question is beyond my pay grade (grin). Nonetheless, I admit I love sailing my JMO-60, it’s huge fun to sail and race, and because of its speed and easy handling, I use it whenever I RD a Big-Boat Race, since I can usually make it back before most of the fleet.
For serious sailing, I’ll chose a boat that’s a closer emulation.