First Look: Mesh Shop Nacra 17 Catamaran

Nacra 17 by Mesh Shop

Kain Xenobuilder is back on the water this week with his latest addition to The Mesh Shop fleet. This time it’s a 2-person racing catamaran based on the Nacra 17 Olympic race boat.

I’ve only had my hands on Nacra for a few days, so I admit I’m still figuring this boat out; there’s a lot I haven’t tested yet. However, the boat hits the water on Friday and there’s a sailing event scheduled for December 21, so let me jump the gun a bit and give you my Quick-Look impression based on a first date. 🙂

New Nacra for the Net

The RL Nacra 17 is a boat born with a mission. The design came straight from the Olympic competition specs for Rio 2016, and the first versions hit the water months ago. This boat has racing in its heart, brain, and yes, it’s brawn too. Take a look:

Dutch (Kain) is no stranger to contemporary race boat emulations; his VO-70 and OD-65 Volvos are accurate and delightfully detailed mesh craftwork. His remarkable level of skill and care are evidenced in the Mesh Shop Nacra 17 as well. Here are just a few close-ups to prove my point:

details Nacra

The first pic above shows the stow-sock for the Genniker. The pink arrow indicates the detail knot in the line-tie, and several green arrows point out similar subtleties of the rig joints.

The second image above is a close-up view of the footing for the two-piece carbon mast. It shows a remarkably well-done minor detail; it’s a true-to-life jam cleat. If Dutch left it out, no one would have missed it.
Well… he didn’t leave it out. 🙂

The third image shows a closeup of the mainsheet tackle. The Nacra actually has a working mainsheet, something I still marvel at in SL. Although every RL sailboat has main lines, it was not included on SL boats until this past summer, when Motor Loon, Dutch Xenobuilder,  Qyv Inshan, and Craig Ktaba decided it was time ‘to get more real.’ (Did I miss anybody’s name?) 🙂

I know this is just a small point, and I fully credit Noodle for picking it up first in the blogs, but I believe those main-sheets set a minor-milestone for realism in SL boats.

Of course it doesn’t stop there. In addition to a working mainsheet, the Nacra’s build includes self-deploying rudders and curved dagger-boards that should match the real life boat spec.

Well, enough with the fine details; you can take off your reading glasses now, then please move a few boatlengths back to get an overview. As the picture below demonstrates, the Nacra-17 is size-wise midway between two other popular SL catamarans: the Trudeau HepCat and the WildWind Wildcat45.

three boats six hulls

Like those other boats, the Nacra 17 is designed to accommodate two sailors. Each can hike through eight positions (four port and four starboard) to help balance the boat for a high-speed, thrill ride.

Nacra 17 crewed

Although it’s obvious I like this build a lot, let me give virtual sailors a fair heads-up warning here before I continue. The Nacra 17 uses the BWind wind system and it is not WWC compliant. It also uses the BWind 2.5 variance scheme, and there’s no wind shadow component.

Those precepts may be hard for some sailors to swallow; for others, it may indicate progress to a different, new standard. I frankly don’t know yet, but I do know that Dutch is trying to sort this out for his boats in a way that guarantees a realistic sailing and racing paradigm in the future.


With that preface, let’s talk about how Nacra sails.

The Nacra 17 uses a BWind 2.5 sail engine with features similar to the two Volvo boats that I’ve discussed earlier.

There’s a “cruising” mode that acts like a standard BWind boat, and there’s a “racing” mode that’s adjustable through a tablet interface. (You can get a free tablet here, and don’t forget to pick up a copy of the manual. It discusses how the wind variance works.)

Bwind 2

The tablet is very easy to use and it gives a skipper or RD a handful of fixed BWind options for wind direction and intensity. Once those are set, any boats in the vicinity can lock the same wind definition to race.


A skipper controls the Nacra 17 using a mixture of chat commands, key clicks, and HUD buttons.

Nacra17 control

Click to enlarge

The boat’s com channel is not adjustable, but that’s probably okay since there are only a few, critical chat commands. Sheeting the sails, turning the tiller, and hiking the skipper are all done with arrow key combinations.

That’s a potential problem since sailing with overlapping key clicks can get pretty messy, particularly when you’re trying to take a sharp turn around a race mark and you urgently need to do many things at once.

If you race BWind boats, you also know that the keyboard arrow keys are woefully inadequate to adjust the sheets on close haul. A click of the up or down key will give you a sail adjustment that’s totally random and far greater than you intended. You often have to toggle the keys back and forth to get the setting you actually want.

Dutch is aware of these issues, and he’s added a simple button-control HUD for the skipper (shown above right). The HUD lets you flip the headsail from genniker to jib, trim the sheets, or hike the sit position.

Nacra HUD

Click to enlarge

The HUD also allows precise sail adjustments in 1° and 3° steps.

There’s a crew HUD as well with the same set of functions, so it’s easy to split up the work while racing.

As shown in the image to the right, the Nacra 17 also has a numerical display HUD that provides basic information about boat speed, compass heading, as well as Apparent Wind and sail angles. The HUD also shows the numerical heel angle to help skipper and crew adjust the hike positions.

Speaking of heel angle, the boat will capsize if you tilt more than 40°. That agrees nicely with the heel effect in the Wildcat45, where the maximum acceleration occurs at 35° and the boat flips at 45°. The Nacra 17 doesn’t pitch pole like the Wildcat though, so that’s one less thing you need to worry about. 🙂

Nacra Capsize


The boat is tuned nicely to sail like a catamaran. It noticeably starts to pick up speed as the leeward hull comes out of the water, and it sails fastest when on heel. The chart below plots Nacra‘s Boat Speed vs Real Wind Angle for a solo skipper using a constant, “default” Real Wind Speed of 15 kn. The solid blue line shows the data for a boat sailing with Main+Jib, and the solid red line gives the same information for the Main+Genniker.

As you can see, the Nacra 17 has a wide range of effective headings that should make it relatively easy to cruise or race. Even with a RWA of 24°, the boat can do 60% of Real Wind Speed. Peak performance is on a beam or broad reach, where the boat hits 120% RWS with the Genniker up.

According to the manual, a good skipper can even get the boat to plane at high speed  on a downwind run, if the boat is riding nearly flat. I haven’t intentionally tried to plane the boat yet, but in lots of sailing with a 15 kn breeze I never saw that effect. It probably takes a stiffer breeze or maybe a better skipper. 🙂

Nacra 17 polar Dec13

In any event, the chart above superimposes data from two other catamarans, the the Trudeau HepCat and the WildWind Wildcat45. The Wildcat turns out to be the fastest of the three (GREEN dashed line above). It has the best upwind performance and a broad range of angles where the boat reaches or exceeds 120% of RWS. That’s no surprise at all, since the Wildcat45 is modeled after the America’s Cup 45 racer, a much larger and intentionally overpowered boat. 🙂 The Nacra 17 is also pretty high-tech, but as the Olympic boat it needs to appeal to a much broader sailing base at a far cheaper total package price. It shouldn’t match the AC45’s speediness in in either RL or in SL.

The Trudeau HepCat’s performance is shown by the PURPLE dashed line on the above chart. It’s the slowest of the three boats, but it should really wear that distinction like a badge of honor. The HepCat’s modeled after the Hobie 16, a boat that is huge fun to sail but without the pretensions of the other two racers. (I guarantee that SL is the only place anyone would ever put up a chart comparing the performance of an AC45 and a Hobie Cat. 🙂 )

It’s interesting to note that all three boats have curves that peak-out at around 120% RWS, so they are a very speedy group. The difference between them has more to do with upwind performance, and how quickly boat speed drops off on far downwind headings.

Nacra17 test drive

Test Tracking Nacra 17

To see how the numbers on the above chart actually affected sail performance, I did a series of repetitive “hot laps” in the Nacra 17, WildCat45, and HepCat and then compared time scores. In that simple test, the Nacra 17 was easily 30% faster than the HepCat overall. The Nacra in turn was 7% slower than Wildcat45, which is still a very good showing in a truly fast crowd of boats.

Those hotlap results are consistent with the speed plots discussed above, and the boat builders’ intentions for each of these vessels.

Doing a large number of repetitive hot laps also makes it easier to get a feel for the boat handling and to see if there are consistent problems that crop up as you sail over the same route many times. In that context I thought the Narca 17 stood up well. The boat is relatively easy to sail, it survives problematic sim crossings, there are very few obvious ‘glitches,’ the polar looks good, and the boat can carve a realistic, sharp turn.

On the downside, in my hands the Narca 17 has a mild lee helm that tends to slowly turn its nose away from the wind unless a skipper redirects it. Most SL boats have a helm bias, so this is no big issue.

I also think the Nacra 17 has poor tiller response. In my hands, most of the time a single tap (or even two or three quick taps) on a L-R arrow key has no tiller effect at all on boat heading. It often takes multiple taps to get the helm’s attention, and that commonly produces an over-correction when the boat finally listens. It takes practice to get it right.

This is an issue, but again it’s not a huge one. The Loonetta 31 has a much worse version of this tiller problem, but I hear few complaints about it from owners. I’ll be interested to see what racers think.

Nacra test drive

Bottom Line

The Mesh Shop Narca 17 is the latest release in Kain Xenobuilder’s fleet of detailed, contemporary sail racers.It’s the SL version of the high-tech catamaran that’s scheduled to compete in the 2016 Rio Olympics. With this boat Second Life sailors get a chance to grab the tiller and go for a joy ride way ahead of any Olympic sobriety tests.

All kidding aside, the boat is beautifully constructed, and it’s fueled by Becca Moulliez’ latest BWind iteration. Although I’ve only sailed it for a week, I’m happy to report the boat is fast, reliable, and true to its real life origins. This is a boat you can bring home to meet Mom and Dad for the holidays. (Get them to crew 🙂 )

The boat’s biggest strengths are it’s great mesh build and it’s BWind 2.5 sail engine; it’s well-balanced and huge fun to sail for two people. However, the Nacra 17 is not WWC compliant, and it lacks Wind Shadow. If those issues are not a factor for you, this boat could be a great choice as your next two-person catamaran.

Go take a look, give it a spin, and see what you think.

Nacra 17 catamaran

Mesh Shop Nacra 17 Regatta

To share his excitement over the launch of the new Nacra 17 in Second Life, (Dutch) Kain Xenobuilder  is planning a Regatta Party next Friday, December 21 at 2:00pm over at The Mesh Shop in Tschotcke. Dutch will provide the details as the event approaches, but I understand Bennythe Boozehound will be there spinning tunes, and sailing is involved. 🙂

Here’s Dutch’s poster for the event. I don’t know who Sepph is, but that’s the boat behind her right hip, in case you missed it.




10 responses to “First Look: Mesh Shop Nacra 17 Catamaran

  1. Noodle’s just posted on this boat too!
    Go read what she thinks here.

  2. Nice post. I haven’t sailed it enough to say much on the sailing characteristics, but I do see the lee helm. Still, the boat is huge fun to sail; About the new standard, I think it is only fair to mention the Fizz for having both main, jib and genn sheets (and a kicker) since I dunno when.

  3. Hi Noodle!
    I certainly agree this boat is fun to sail.
    However, I think you mis-read my comment about a ‘new standard.’
    This is what I said:

    “Although it’s obvious I like this build a lot, let me give virtual sailors a fair heads-up warning here before I continue. The Nacra 17 uses the BWind wind system and it is not WWC compliant. It also uses the BWind 2.5 variance scheme, and there’s no wind shadow component.

    Those precepts may be hard for some sailors to swallow; for others, it may indicate progress to a different, new standard. I frankly don’t know yet, but I do know that Dutch is trying to sort this out for his boats in a way that guarantees a realistic sailing and racing paradigm in the future.”

    I think it’s clear I was talking about the unique wind system in this boat and I was guessing what some might think of it.
    I actually mention three catamarans in the article. Each uses its own wind engine and each is modeled after a distinct RL vessel. I like each and all of them.

    The Nacra 17 might set a ‘standard’ of sorts, but it’s too soon to tell, and this was just a first look. 🙂

    You comment “I think it is only fair to mention the Fizz for having both main, jib and genn sheets (and a kicker) since I dunno when.”

    Noodle, I have great respect for the Fizz. It’s a great dinghy racer. I posted about it with affection several times this past month. However, Nacra 17 is a catamaran based on a different sail engine and it’s designed to meet very different criteria. It’s not a Fizz, and it doesn’t pretend to be.

    The Nacra should be evaluated on its own terms, and I think you would agree.

    • Yeah! You’re right about that Jane. I misread it, as if you meant there was a new standard formed by the new gang of boats with sheets. You can just delete my comment, if it confuses matters 🙂 Whatever the Fizz is, it is irrellevant in this context.

  4. I am afraid that none of the available sailing engines in SL is close to truly emulate the sailing characteristics of a cat. Fizz engine and all its settings/tunings is certainly the closest to realism, but requires hours and hours of tests for a fine tuning. It also would require few adjustements for a good cat. (eg: sailing/surfing waves is not the same at all with a dinguy or a cat)
    Lack of windshadow sounds like a step back for me.

    • Sad but true; Reading the manual of the BWind 2.5 it is obvious that the 2.5 is more interesting than the 2.0, but it remains a W, not a WWC. Still, the Nacra is great fun to sail.

  5. One small semi-correction!
    Dutch reminded me that the boat has an undocumented chat command that lets the owner switch the communication channel. The command is “channelXXXX” where XXXX is the number of the new COM channel you want to use.

  6. Woots, go read Orca’s “First Impression: Nacra 17…
    Orca does a nice test-sail review, and in the middle adds:

    “I was about to complain about the HUD that comes with the boat. Why? Because it bugged me that I can trim the sails with arrow up/down keys but only move Orca’s ass by HUD. That makes me even more clumsy than I usually am.
    Only after I finished my testsail I rtfm and learned the hud isn’t even needed. I can trim, raise, lower the sails and move my avie all with just keyboard commands and arrow keys.”

    I thought Orca made two great points.

    First, she reinforced Jane’s Primary Directive, Rule #1A&B for testing boats:
    1A. Never Read The Manual.
    2B. If You Can’t Figure Something Out, Disregard Rule 1A.

    Second, and I’m not sure about this,
    I think Orcs may now appreciate why the Skipper HUD is actually included in Narca 17.
    As I discussed in the post above, a skipper can sail the Nacra 17 without a HUD.
    However, when the boat hits a sharp turn, the skipper needs to suddenly start hammering on overlapping arrow keys: Up/Down to sheet, Left/Right to steer, and Shift-Left/Shift-Right to hike. It’s a stressful enterprise and I don’t think I ever got it perfectly correct.
    I’m not sure the HUD solves the problem, but at least it gives you more control options!
    That’s why it’s there. 🙂

  7. Go read Ralf80 Titanium’s review of the Nacra 17 too.
    He makes several good points. 🙂

  8. Pingback: Nacra 17 – Blue's Fantasy

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