Mainsail Notes

a)     Batten tension compliments batten stiffness. To depower, loosen battens to the point they can wiggle. To power up, can go quite type, until battens go out of alignment vertically. Each battened can be tuned as such to conditions and stiffness. This is quite an important setting, so teams need to practice setting tension and describing how to replicate their settings. For sure if teams are struggling with righting moment (heal) loosening the battens can be a big help.

b)     Outhaul – you can pretty much just fix it in spot and forget it, or you can mess around by eye a bit if you want.

c)     Max cunno is found from a variety of ways, from risking breakage, inverting the sail, pulling draft too far forward, and fixed measures on the mast. Sails will shrink if unused over time, and adjustments to the fixed range have to be made as such, but teams should spend effort figuring out a safe max.

a.     Every mast you have should have a clear and consistent gauge so you can easily find your max and stick to it. It will be slightly different for each sail, 1-2 cm between a new and old mainsail.

Dynamic Sailing Strategies and Options

Platform Setup

Hulls and Cross Beams

Buying a new or used boat for Nacra 17 racing is a critical first step to getting racing. Pretty much any new generation (2017 onwards) Nacra 17 has the potential to race very competitively to an elite level. Teams at the 2024 Olympics used boats ranging from 2018 to 2024 and did very well with them. Of course, not every boat is perfect, but nothing in the design or building spec has changed in that time and the boats seems to last a very long time, and are extremely durable, especially compared to other Olympic classes.

When setting up a platform, the first thing to do is get it square. Hulls parallel, hulls must be vertical, and the waterlines level. Use a transparent hose with a water bubble ensuring there are no air bubbles in line. At stern use sharp corner between the stern and the canoe body. At the bow, use a point at the middle of the round  of the bow (by eye, it’s ok to miss by a couple mm over that distance). Go stern to bow, bow to bow, stern to stern, and cross ways (kitty corner) as well to ensure the whole boat is square and true. Parallel hulls and vertical hulls is the goal. Using packing in the beams to make your adjustments.

Part of the tuning is figuring out whether you want to include front beam pre-bend or not within your overall set up. Top teams use different approaches, but be sure which you are using when you set up to better get ahead of further tuning you might do. One option is to use about half of the pre-bend you intend to use, something like 5mm pre-bend. Which ever pre-bend you choose, the main thing is to get your boat level and square before starting everything else.

Rudders and Elevators

Setting up the rudders/elevators is a critical piece of the puzzle. Note, the transoms of the boat are not perfectly square or perfectly consistent. Teams must establish a plane by which to measure everything against. You are looking for 90 degrees to the square of the boat. Use an angle measurement device:

-Which apps

– Which measurement devices

Find a location on each transom that ends up being 90 degrees. Mark that point with an outline like in six sigma, so you know exactly where to put your measurement tool every time. Do this for each transom. Even 0.2 of a degree in this plane matters, so be precise. For example, a flat water non-windy set up might have the farthest aft elevator position at negative 0.3 degrees, while that will not be sufficient in a wavey and windy venue, where negative 0.5 degrees should be the base set up. That is the level of precision required to get sailing properly. 

The next piece of setting up the rudders/elevators is to have a device to make a consistent square to the elevator.

Here is a 3d file for anyone to print.

Ensure this device fits perfectly, as even a tiny variation in how this sits consistently will lead to varying results and imperfect set up.

Now find the perfect balance of the rudder and angle to the elevator.

We will simultaneously fix two critical elements of tuning. Angle of the rudders fore/aft and subsequent angles of the elevator to the boat. The elevators are fixed to the rudders and teams can manipulate the angle the elevator is fixed to the rudder and also adjust the fit within the rudder and the rudder box.

If you have too much aft rake then steering at speed is very hard. If the rudder is too vertical, then the boat becomes very twitchy during gybes.  Ultimately, a good starting point for the elevator angle of attack is 3.6 degrees to negative 0.4 degrees.

Set the rudder box.

You can use tape within the rudder box to ensure the rudder is grabbed perfectly every time in the correct position. Use proteck tape or similar on the front top rudder box bearing. On land you can use a strong light to see if there are gaps in your tape to ensure you have a lot of gripping surface along the whole length of the rudder box.

The plastic bearing in the back of the rudder box also must fit your rudder set up perfectly to ensure the rudder remains in the same position. This will require ongoing maintenance. If it wears out, your angles will change.

Set the elevator to the rudder

The elevators screw into the rudders, but they really should be glued using epoxy to ensure they don’t get pulled off. Use a mclube or wax or another substance that blocks the epoxy, so that you can unbond the join between the rudder and the elevator, which you will need to do. Set your boat up with the 3.6 degree to negative 0.4 degree angle, and then see how twitchy it is during gybes. You will need to using trial and error to find the correct combined angle of the rudders/elevator to get your boat working how you want it. Have a system to fix and check the elevator angle so you can make small adjustments precisely and make improvements to your set up, not guesses.

Daggerboards

The element 6 daggerboards (post 2021) are made from different tooling than the DNA daggerboards (2017-2020). They are both the same design, but the end result of the different tooling methodology and execution means the two groups of daggerboards are not exactly the same geometry as each other. Both work for Nacra 17 racing, and both were used at the 2024 Olympics, but the DNA boards are not as consistent and more and more teams are racing on the element 6 boards at the time of writing.

Rudders Elevators

Teams should pay attention to the rudders, aiming to get a set that ‘track straight’. It is possible that some rudder will slowly drift one direction or other, and the sign of a good set is that they don’t do that. Top teams use both DNA and Element 6 rudders.

Elevators are machined and come out very consistently from the factory. The do seam to wear over time, and teams do tend to replace them over a season. The class rules do not allow them to be refinished (currently) for fear of manipulation, so teams should check for smoothness of their elevators

Platform Geometry Double Check

At the 2022 and 2023 World Championship, all the boats competing were measured thoroughly with special attention paid to the platform geometry. Reviewing the data it became obvious that there is a very small amount of variation within the fleet, especially with the top sailors.

As such, we have decided to publish the average measurement data of the critical platform geometries so teams can check their own boats and know they are close to what everyone else is using. You should assume that all the top sailors were racing with their platforms very close to this geometry at the 2022 Worlds.

The 2023 geometry confirmed the 2022 geometry measured, and the main reasons behind publishing the average numbers remains the same. All teams should know that boats setting at these numbers can be world elite competitive, as demonstrated by the boats doing so at these geometries.

These measures were taken with the platform in racing trim, so with beam bend on but without rig tension.

Here are some average measurements of the platforms.

Bow to Bow – Average 2178 mm (2022) – 2177 (2023)

Measure across front of hulls from the centre line of the bow of the starboard hull to centreline of the bow of the port hull at the chine height.

Transom to Transom – Average 2191 mm (2022) – 2193 (2023)

Measure from inner edge on port hull to outer edge of the starboard hull, measured across the line formed by the underside of the top transom gudgeon fitting.

Toe In Toe Out – 10mm (2022 and 2023)

Support the boat on trestles and place the boards fully down and set at the zero rake point. Measure across the bottom of the hulls between the centre line of the two boards and at the exit point of the board from the bearing. Take one measurement between the leading edges and one measurement between the trailing edges. The difference between the two numbers gives you the toe in and toe out measurement.

Lower Bearing to Lower Bearing (aft) – 2264 mm (2022) –

Measure across the platform, underneath the hulls, from the inside edge of the port bearing at the bolt point to the inside edge of the starboard bearing at the front bolt points. Measurements taken at the aft bolt point are within +/- 1mm of the front measurement.

Daggerboard tip to daggerboard tip – 860mm (with slight inward tension) (2022) – 857 (2023)

Support the boat on trestles and place the boards fully down and set at the zero rake point. Measure between the tips of the boards with light pressure pushing the tips together to take out any slack.

Rudder Rake adjustment range – 4 degrees     (4.05 degrees max) – a note about this. There were a few teams that has range of motion below 4 degrees. It is likely this is caused by over-tension of the spring, which improves ‘pull’ of the system, but limits performance. Teams should pay attention to ensuring they have the full range of motion in their rudder rake adjustment system.

Daggerboards

At the 2023 Worlds, there was also the addition of foil scanning to our measurement procedures, whichl will occur at most future regattas and at the factory for new foils. Here is an initial report from World Sailing on the topic.

The main conclusion from this report is that the Element 6 built daggerboards are much more consistently built thank the DNA ones were. Almost all measures taken of the E6 boards were in a very small range from each other. This bodes well for the long-term future for the class and its ability to provide consistent equipment for all sailors.

The DNA boards erred to the thick side in some areas and the thin side in other areas, and were generally less consistent too.

From a competitive standpoint, 13 of the 20 foils used by top 10 competitors at the 2023 World Championship were Element 6, including all 6 boards used by the medalists. So not only is the consistency of the E6 boards excellent, but they are also world class in speed, if not the fastest available. While good results are possible on the DNA boards, as demonstrated by there being competitive finishes using the older equipment, teams who are improving in their skill profile should migrate toward the E6 boards knowing it is the right solution for sailing well now and for the class tightening up our measurement requirements.