Twelve gets you Twenty at Trudeau

Originally posted to SLSailing.com on October 16th, 2008

A few weeks ago with very little fanfare Jacqueline Trudeau gave a nod and the small travel lift over in Isla de Jacqinda sputtered into action, gently lowering a small but sturdy wooden ship into the calm waters of USS-South. Trudeau Twenty, the newest addition to the Trudeau Classic Yacht fleet, was on the water and ready to sail. The T20 is the first of a series that set a new standard for design and sailing performance in the Trudeau fleet. The boat’s innovations are carefully balanced to produce a ship with an authentic, highly detailed appearance coupled with an advanced sailing algorithm that faithfully emulates the boat’s real life performance for both cruising and racing. Here’s a quick list of the highlights before we get into the details:

• The T20 was inspired by the Herreshoff 12 ½. The SL adaptation is 20ft long LWL (hence the name Twenty).
• The T20 is a one part “rideable” boat with a sculptie hull (there are no attachments). The boat weighs in at a mere 27 prim, which leaves room for a skipper and three passengers.
  
• The T20’s sailing algorithm uses apparent wind, and the boat’s sailing characteristics are tuned to give skippers the feel of the H 12 ½ , adapted for SL.
• The T20 introduces mainsail reefing to the list of Trudeau sail adjustment options.
• The T20 also incorporates a series of racing features, including a newly developed wind shadow system. The magnitude and extent of the wind blanket is appropriate for the T20’s size, and the system was fine-tuned over several weeks of in-water testing by many sailors from SL’s race fleets.

The combination of features in this boat are truly exciting and technically innovative, and they set the bar a rung higher for future SL sailboat development. The boat is also intuitive and highly user-friendly; it’s a great choice for sailors of all types, whether your passion is a tactical shoot-out on the raceline, or when you prefer a romantic sail with your partner exploring SL’s unending seas.

If you have a short attention span, you can stop reading this now and click the surl below. That’ll take you to the Trudeau marina at Isla de Jacqinda where you can pick one up for yourself! For the rest of you, I have lots to say about this upcoming family of boats…

http://slurl.com/secondlife/Isla%20de%20Jacqinda/97/183/23

Betas Make It Better

The smooth integration of features, user-friendly interface and tough reliability of this boat of course was no accident.  Jacqueline Trudeau has long experience and a strong reputation for building great boats that are well-known for their careful attention to detail and repeated upgrades in response to user’s interests, technical innovation, or SL advances.

Since T20 was a new and in some ways radically different boat for TCY, J Trudeau took an interesting extra step in its development.  When the boat was 95% finished and looked to most of us like it was only a few days from launch, JT decided to beta test it and get user feedback.

The beta testing was actually pretty fascinating. Copies of the boat went to a mix of nearly two dozen SL sailors that included people with strong experience racing and cruising in both SL and RL. The testing period lasted for several weeks, and – amazingly – the boat went through eighteen beta revisions along the way. Ihe beta test process brought racers and cruisers together on a project where they had common interest (pretty unusual usually); there were good discussions, lots and lots of sailing, and a few authentically scary moments even… Like the day M1sha, Liv, Bea, Glorfindel, Julia and I raised out beta sails together… and our combined scripts immediately crashed Manning Strait so badly, the sim actually went back in time, and there was a worrisomely long, long delay as it started back up. I’m not sure Bea ever made it back that day (grin).

Anyway, the beta testing provided a way to get pretty intensive feedback from a large number of experienced skippers with different sailing interests. Over the 18 revisions, a large number of issues were discussed concerning the boat’s features, performance, and user interface, and the inevitable half dozen really obscure bugs were discovered. All the information went back to J Trudeau, who squashed the bugs and integrated many of the suggestions and recommendations into new versions of the boat. I think the beta process can be a great way to polish and fine-tune a boat like T20, with the understanding that the boat designer is the one with the creative vision, the person who makes the decisions and controls the process. J Trudeau took the time to listen and respond to a pretty continuous flow of comments and suggestions from beta testers over several weeks. She also knew where she wanted to go, and pulled the testers along with her vision. It was a fun ride.

It’s interesting to note that, although I can be pretty cranky reviewing some boat issues, and I complain, sometimes loudly when i think there’s a problem with a boat, I have very few complaints about the T20.   it turns out there’s a simple reason: only issues I had, and I think everybody else had, got thoroughly discussed and worked in beta. (Hey, it’s cheaper than therapy.)

Now let’s talk about the boat!

The Boat.

Nearly all Trudeau boats are modeled after RL sailing vessels, so there’s usually a fixed target for physical specifications and performance.  These serve as guidelines rather than fixed rules, however, since considerable tweaking may be needed to translate the look and feel of the boat to Second Life waters. The T20 was inspired by the Herreshoff 12 ½, a small, full keel, gaff-rigged boat. Nat Herreshoff designed it nearly a century ago to teach children to sail (the boat was originally known as “The Buzzard’s Bay Boy’s Boat“). Well, like many other boats in the Herreshoff line, the H 12 ½ quickly became a classic. Those kids that grew up sailing the H 12 ½ ?  A lot of them still sail it! Although only 364 were made by the original company, over 3,000 copies of the boat were released by different yards over the years, and the boat remains a popular racer and daysailer today. New England has the largest H 12 ½ fleet, but the design is recognized and respected in marinas around the world.

J Trudeau took her inspiration from the H 12 ½’s simple classic styling, a boat that teems with history, fun and tradition,  and she breathed that life into the Twenty.

Here’s a picture of Kent Messmer at the SYC start line last weekend. He’ll race without hair and without a shirt, but he knows the tradition that comes with these boats; he won’t race without sporting the “H” insignia on his sail!

At first glance T20 may seem small and unassuming in comparison to past Trudeau Yachts creations, but don’t underestimate this boat; good things do come in small packages. The T20 is the first in a totally new generation of Trudeau yachts that use current design and script technology to emulate RL boat-specific sailing characteristics while also providing easy-to-use helm control for novice and expert sailors alike. The result is an expertly crafted pocket racer that looks and sails like the RL H 12 ½ . Unlike any prior Trudeau boat, the T20 uses apparent wind, incorporates mainsail reefing, and offers realistic windshadowing for tactical racing. Let’s crank some details below!

I’ll have mine sculpted, please

Second life vehicles (for example, cars and planes and boats) have a maximum size of 32 prim. To get around that limit, many of the boats in the Trudeau Fleet come in two parts. The first part is the basic vehicle frame that contains the sit positions and scripts that make up the sailing physics algorithm that powers the boat. The second part is an attachment the skipper ‘wears’ on his/her pelvis. Attachments allow boat designers a free hand to construct beautifully interpretations of RL vessels. The Trudeau Tradewind, Trucordia Yawl, SWB Atlantic 75 and Verkin Raven’s Tetra 35 are all great examples of the detailed artisanship that often goes into attachments.

However, attachments have their own problems and frustrations, so the Twenty takes a new approach with sculpties. J Trudeau’s fashioned a wonderfully detailed, one-part boat that’s a dead ringer for the real H 12 ½ …and its a mere 27 prim! Take a close look at the boat when you see it; the detailing is pretty miraculous at that prim size. It’s a boat pretty enough that you’ll want to have it on display and hang out on it when not sailing. And the picture above shows the attention give to small issues… I’m sitting in the crew position on the port bench. I’m not sitting 30cm above the bench or 30cm inside the bench. The sit position actually puts my but and sneakers heels ON the bench. It may seem like a small thing (the alignment, not my butt), but how often do people get the poses lined up exactly right? Darn, I love this boat.

Keeping the total prim count below the vehicle maximum has a big practical dividend for the user. It means  the T20 acts like a real boat, rather than a clothing attachment you clip to your pelvis. You can finally give your pelvis a break and leave the T20 permanently rezzed in SL; it fits quite nicely in a Tako-sized dock slip. When you want to sail, you can do exactly what you’d do in real life: go over to the dock, climb aboard, raise sail and cast off!

You’ll be glad to hear that the textures for the T20 are fully mod, so owners can personalize their boats. To make that process even easier, J Trudeau has posted templates and instructions on her website.

The boat has sit positions for a skipper and three crewmembers who can all share sailing responsibilities through chat commands and a HUD.  T20 owners can even share skipper permissions by listing their friends’ names on a notecard. That option can prove convenient if you use the boat to teach new sailors.

HUD and Chat Command Control

There are two new chat commands that you’ll recognize from your old Tako:

• BOAT ID: “/1 id 0000” — where 0000 is any letter-number string, such as JF82.
• DOCKING: “/1 set dock“ sets your mooring location. The command “1/dock” returns your boat to that spot, so you don’t have to maneuver in a tight marina.

Since the T20 only has a jib and a mainsail, the standard gestures you already use for other Trudeau boats will probably work here too, although you’ll probably want to add extra gestures to control the reefing points.

The T20 HUD is similar to the Sloop HUD used by other Trudeau Yachts. If you have a HUD fetish (and frankly, who doesn’t?), you already know J Trudeau released several significant upgrades to the Trudeau HUD this past year, introducing audible and visible “luffing,” and several other nice features. The HUD has a series of analog dials that fit nicely at the bottom of the screen, leaving your view unobstructed. The T20 HUD also includes new buttons that control sail reef positions. If you’re one of those people who “sails by the numbers,” don’t worry. Just click “i” on the HUD and you’ll get a numerical info display.

Another nice feature: You can edit the HUD to change its size and position, as well as the sound effect loudness and default sheet adjustments. The default sheeting buttons move the sails in 5° steps.

For cruising, the Trudeau sloop HUD is full-featured, easy to use, and proven rock-solid during months of use in other boats. While beta testing the boat for racing, however, the test group found that large race fleets induced considerable lag that resulted in a frustrating delay in HUD information updates. This problem was largely fixed with the introduction of a second, bare-bones “info HUD” for racers. Both HUDs are included as standard equipment with the T20, so use the one that suits your mood.

Wind

The T20 is the first Trudeau boat to use apparent wind. You can toggle the HUD display to show either “apparent” or “real” wind speed with the chat commands “/1 app” and “/1 real“.

“Real” (aka “True”) wind is the wind speed and direction a boat sees when it’s stationary. Most boats in SL, such as the Tako and ACA33, use this real wind to calculate lift effects that power the boat through SL waters. The wind forces driving a sailboat in real life are a bit more complicated, however. As soon as a boat starts to move forward, air resistance results in a back pressure, or “headwind” blowing from the bow.  That means the wind the boat actually sees is the sum of two wind vectors, the “real” wind and that “headwind” caused by wind resistance. That combined wind is the wind vector that actually drives the boat. It’s called “apparent wind.” If you want to see how apparent wind changes with boat motion, but you forgot any trigonometry you ever learned, there’s a convenient online apparent wind calculator here. And if you spend an afternoon plugging numbers into that webpage instead of just going sailing, perhaps we need to have a chat in private about your priorities…

Several SL sailboat designers have championed the importance of “apparent wind” as part of the sail algorithm for SL boats, and it’s already an integral part of sailing and racing in boats such as the ACC2, the Flying Fizz, and Caf Binder’s recently released Jangars. Now you can add the Trudeau Twenty to that list.

If you’re used to a Tako, which has Kanker Greenacre’s original sailing algorithm that only uses real wind, you probably want to know the bottom line here; What’s the practical effect of apparent wind on how you sail?  Well, you’ll need to pay a lot more attention to your heading and sheeting, because as the T20 accelerates on close haul, you’ll notice that the apparent wind speed escalates in intensity and the apparent wind direction shifts towards the bow, since the headwind increases as you pick up speed. With a little practice, you can anticipate that effect and set an initial heading below your target point of sail; the boat will then slide into the right heading and it picks up speed.

For example, if you set an initial heading of 48 degrees apparent, as your boat gains momentum the headwind increases and the apparent wind direction moves towards the bow. Your boat will end up settling on a heading closer to 40 apparent. If, instead, you treat the T20 like your old Tako and just ‘point and shoot’ it at a 40 degree heading as soon as you raise sail, you’ll soon be sadly sorry. The T20 doesn’t accelerate very quickly at 40, and as soon as it does pick up speed the heading will move upwind into the mid 30’s. Believe me, T20’s don’t like that, and you will end up continually fighting to keep the boat from luffing as it tries to build windward speed. So hey, don’t fight it… just get a feel for the amplitude and pace of the wind adjustment and let it work for you. T20 wants to dance with the wind, and its pretty easy to learn not to step on its toes. Oh, and that old Tako of yours…? it doesn’t even know the music’s playing.

Speed and points of sail

Based on its size, the real-life maximum hull speed for T20 should be around 5.99 knots. Due to some SL nonstandard conventions and arbitrary historical decisions (Please note I did not say “dumb mistakes,” OK?), the windspeeds common for sailing in SL are about twice what they normally are in RL. the simplest way to adjust for that is to think of knots as equivalent to SL meters/sec. In that case, the T20 is probably right on the nose; 6m/s is near the top speed for the boat.

Based on the PHRF hotlaps results, the late beta T20’s were about as fast as a Trudeau Sojourner, and had a handicap factor of around 0.68. At the time I’m writing this, there are not sufficient data points to report a bulletproof handicap for the T20 final release boat, although several skippers (M1sha Dallin and myself included) feel the boat is slower.

I inserted a plot here showing the Speed Over Ground for the T20 with a constant, true wind of 5 m/s.  That low wind speed was selected so that sail reefing would not be a factor.  The chart shows the boat speed for different apparent wind headings and optimal sheet settings.

As you can see, the boat probably makes it’s maximum velocity on a reach, and on headings from 50-100deg  apparent the curve is relatively flat.  At any of those points of sail the boat speed reaches a maximum of about 60% of the apparent wind speed.

But now look at the left side of the curve, on the upwind points of sail. As the T20 moves upwind, the boat speed falls off a cliff.  A heading of around 40° apparent wind is probably the best one can do on a beat, and even that sacrifices a lot of power.  Pinching over 40 even a small amount on the above curvecould be extremely costly with a major loss of forward motion going from 40-38.

But here’s a caveat: remember everything above is done at  a constant real wind speed of 5m/s.the chart shows the boat speed at different apparent headings, but as we discussed above, the relationship between the real heading and the apparent heading changes depending on the boat speed. The shape of the curve above is probably the same with higher real wind and faster boat speeds, but the headings may change.  one thing that certainly changes with faster boat speeds is the difference between the apparent heading and the real heading.

In a tako they are both the same thing.  If you want to go to a target 40deg off the wind, you set your course for 40 and sheet appropriately. In a T20, the apparent heading includes the headwind. With normal wind speeds of 10-11m/s, Once the T20 has reached a speed on an apparent course of 40, the real course is usually around 60 (to balance out the headwind)! I know at this point you probably want your old Tako back, and yes, I understand; I’m sorry. Sometimes the real world is difficult.

Go back and look at the Speed curve above again for a moment.  If you look at the right side of the graph, you can see the downwind speeds as the boat gets closer to a dead run.  There is a marked drop-off in speed with a fairly constant slope over 110°. You can compensate for that, however, by winging the sails (Putting the jib and main on different sides). I’ve looked at winging in many of the Trudeau boats, and this one is similar; T20 may even had a bigger boost with winging than earlier big-boats boats.

It does not make a difference whether you wing the main or jib sail, but the winging boost is substantial and increased boat speed by approximately 34%  at an apparent heading of 176.

What heading should you start to wing? if you look at the curve above, the pink line shows boat speeds with winged sails.  with an apparent heading of 130, the boat moves slower with winging, but at 150 there is a definite effect.  The crossover (the point where it makes no difference) is approximately 140°.  Because this boat uses apparent wind, it’s more difficult to do these measurements under controlled conditions since things are often changing and it’s hard to tell if you have reached the maximum velocity at any point of sail.   It’s probably worth noting that I have looked at this very carefully in the Trudeau Tahiti Ketch, where it is much easier to get accurate data points. I then went and compared that boat to the rest of the Big Boats on this issue. The Ketch seems to have a crossover point at 135 degrees, in my hands under normal constant wind conditions. there is a definite boost with headings of 137 and above, and a definite loss of power from 133 down.  My guess is that the T20 has a similar crossover but the present measurements just indicate it is someplace close to 140.

Since we are talking about different points of sail and boat speed, let me add two more things before I forget them.  The first is that T20 is extremely sensitive to sail sheeting adjustments. with an heading of 40°apparent wind, The optimum sail angle is 20. There is a small but significant, easily noticed loss of power with settings of 19 or 21.  The reason I’m emphasizing this is the default sail adjustment step on the HUD is 5°; that may be fine for cruising, but if are racing, you may want to change it,  or even better use one degree gestures.

The second thing I wanted to mention, and I guess this may be obvious, is that the T20 is a ‘keel boat.’ it’s going to have a wider turn around markers than a Tako, Fizz, or other boat with a centerboard or dagger keel. it may take some practice to decide when to begin a sharp turn and how much room to give. That’s probably true for another reason;This is a small boat and it backwinds easily if the sails are set incorrectly. if you’re reading this article, I’m sure you are a wonderful sailor and would never incorrectly sheet your sails, so I apologize for bringing it up, but… the problem does occur when you gybe around a race mark.  If you miss flipping your sails by a second or so, the backwind effect will take a big toll on your momentum. It quite literally will knock the wind out of you.

OKOK, I knew this was going to happen.  I have tons more to talk about with this boat, but I’m running off on tangents and I really want to go race it, and not just talk about it. I’ll post the next part is soon as the weather turns lousy so I can’t sail!