Performance Guide

For The

August 2007

Introduction Ockam Instruments has worked from the beginning of the NYYC Club Swan 42 to develop the most advanced instrument system available. We are continually working to refine base calibrations and polars for the class. It is our goal to facilitate the calibration process so that all of your efforts go into the boat’s performance on the racecourse.

System Installation Your Ockam Instrument system has been professionally installed by a certified Ockam installer. The initial base calibration has been done and entered into the memory of your system processor. The following is a brief overview of the calibration process of the Ockam system. An explanation of the complete process is explained in Section 3 of your Ockam System Manual.

Calibration You will find the actual process of calibrating your instrument system extremely rewarding and beneficial to your use and understanding of the system. As a result, your confidence and use of this tool on the racecourse will increase dramatically, and you will benefit from many of the addi-tional built-in features of the Ockam instrument system. The secret to good calibration is an organized, methodical approach that goes one step at a time. In the early stages you will lay the ground work for the overall performance of your system. As in most instances like this, a well done job at this stage will make the calibration of the total system easier and more accurate. DOCUMENT WHAT YOU DO! You should keep a log on each calibration adjustment. In this way you will know what the current adjustment should be (in case it is inadvertently changed). When you make an adjustment you should enter the date, who made the change, the new value and the reason for making the change. In this way, if you find that you are going adrift after changing a number of different calibrations, you can then go back to the setting that you started with. Calibra-tion worksheets and records are at the end of this section. Calibrating your instrument system conjures up visions of fine tuning the six dual throat carbure-tors of your 12 cylinder Ferrari. Our goal in providing this guide is to take the mystery and magic out of calibrating your instruments, by giving you a straightforward, step by step system of ap-proach to the procedure of calibration. You don't need a witch doctor or white gloved technician to get the instruments straight. Time, at-tention to detail, and a methodical approach are the only requirements. Time and again we are called to help with this process and when we finish, the owner says "I could have done that my-self". Absolutely correct. There is no inherent difficulty in the calibration process. There are three sensors which provide the information necessary to compute the Wind Direction solution: the boatspeed paddlewheel, the masthead unit, and the electronic compass. The quality of the installation is vital to ensure that the information the instrument system is receiving is ac-curate, and that your efforts in calibrating the Wind Direction solution are fruitful. Inaccuracies caused by improper sensor installation cause errors that are hard to identify. Be especially careful that sensors are securely mounted. Loose sensors introduce random errors that come and go, and cause no end of frustration. The correct foundation must be laid in order to develop maximum accuracy in the Wind Direction solution.

Weather Conditions

Picking the right weather and wind conditions will make the calibration process much easier. Ideal conditions are a steady 10 knots of wind, flat water and no current or wind shear. Calibrating is

harder to do as conditions deviate from ideal and should not be attempted in unsteady conditions or in very light air.

Wind shear & Gradient Wind shear as a change in wind direction with altitude, and wind gradient as a change in wind speed with altitude. Shear and gradient are ALWAYS present, but not always to a noticible extent. In the spring (during calibration season), with warm air over cold water, the effects can become quite pronounced. If you don’t believe in wind shear, the next time you’re out tacking upwind on a nice sunny calm spring day, take a look at the windex on each tack and you’ll see what we’re talking about. Shear and gradient do not affect the validity of the wind direction solution – the top of the mast is

pointed in the same direction and going the same speed as the hull. However, wind shear makes tack-to-tack comparison of wind angle and boatspeed impossible. There are a lot of non-believers out there, who, once they “get it” realize that knowing when the instruments tell them that wind shear and gradient are present, use the information to help them control the boat better. The photo on the right is of a 64’ boat on the east cost with well-calibrated instruments. Note that heading and wind direction are both 288º (i.e. zero true wind angle), and yet the boat is trucking along at over 9 knots! The jib is trimmed on port, but the top is plastered against the mast. Not a good day to calibrate. The photo on the right was taken while sailing in Block Island Sound. Note the Wind direction and TWA. There is approximately 37 degrees of sheer present at the top of the mast.

NOTE The calibration steps where boatspeed offset and windangle zero are adjusted

should not be done when wind shear is present!

Setting Depth & Depth Offset Using a lead line, measure the depth of the water while at the dock. Put Depth Surface and Depth Keel on a Matryx display page. On the T2 interface located in the starboard forward lower locker, adjust the screw pot labeled Xducer Depth (1

st) so that the surface depth is what you

measured on your lead line. Next adjust the screw pot labeled Depth Keel (2nd

). The depth desired , while still at the dock is obtained by subtracting the length of the keel from the waterline from the Surface Depth.

Compensating the Electronic Compass

It is absolutely critical that your electronic compass is compensated by a qualified compass ad-juster for 0° of deviation. Be aware that until recently compass adjusters were usually satisfied

Wind Gradient

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with 3° to 4° of deviation. Deviation of this magnitude has a direct effect on your Wind Direction solution. For example, if you tack through 90° (true wind angle of 45° on each tack), but because of deviation the heading in the electronic compass only changes by 86°, the instrument system can only resolve this difference by indicating that the Wind Direction has shifted 4° when you tacked. When compensating, have the compass adjuster remove the electronic compass’s internal mag-nets and use compensating magnets which are fixed to the boat, located at least 2 feet away from the electronic compass. This will necessitate having relatively powerful compensating magnets available for this purpose. Using the internal compensating magnets causes errors in the compass readings when the boat heels. Having external compensating magnets located away from the compass virtually eliminates the heel errors which otherwise would occur.

Setting CAL Boatspeed Master

Boatspeed transducers measure water flow close to the hull, but have to be adjusted to read the boatspeed thru the water. The reason that flow near the hull does not equal boatspeed, is that the hull distorts the flow near itself. Calibrations for boatspeed are therefore required to compensate for hull shape and the position of the transducer.

Boatspeed can be calibrated in many ways: timed runs over a measured distance, comparison with a good standard (ie another boat known to be well calibrated, or a towing calibrator), dead- reckoning, or a combination of these. You should use the best standards available and should continue to further improve the calibration as you gain more experience.

If you use calibration by time between marks, make timed runs over an ACCURATELY MEA-SURED distance of at least 1/2 mile, going over the course in both directions to negate current ef-fects. Remember to keep as straight a course as possible, because sinuous courses always make the actual distance traveled longer than measured. Also, if you are powering or being towed over the course, prop wash will make the indicated boatspeed higher than actual. Both of these effects tend to make your calculated boatspeed lower than it actually is. Take the log readings over the course in each direction, trying to interpolate to 1/1000 mile.

Repeat the procedure several times until the applied corrections are less then 2%, which is about as good as running a measured course can do. CAL Boatspeed Master Worksheet Example

Find a known course at least 1 mile long. Course distance = a______ 1.05

Run measured mile at slack tide and no wind. Out run Back run Out Back Make sure the boatspeed is steady before you begin. Record the measured distance from the Trip Log. Run #1 _______ _______ 0.99 1.03 Run #2 _______ _______ 0.97 1.01 Run #3 _______ _______ 1.01 1.05

Average of the runs b______ c______ 0.99 1.03

Average distance on all runs (b+c)/2 =d______ 1.01

Boatspeed correction a/d=e______ 1.04

Present Cal Boatspeed Master reading f______ 1.01

Set new Cal Boatspeed Master reading e•f=g______ 1.05

Setting CAL Boatspeed Offset & CAL Wind angle Offset

For all the sailing calibration time, you should look for a developed breeze of around 12-14 knots, generally later in the day. Choosing these types of conditions help to reduce the possibility of wind shear (changes in wind speed with altitude) and wind gradient (changes in Wind Direction with altitude) which are often present early in the day, when the breeze is light or the sea breeze is developing. Cold water and warm air (especially in the spring) can also cause wind shear and gradient.

For the calibration of the two above functions, you will want to sail upwind to gather sufficient data to calculate the necessary changes in the calibrations. This normally will require between 30 and 45 minutes of concentrated upwind sailing. The purpose of these two calibrations is to develop symmetry in boatspeed and apparent wind angle readings from one tack to the other. Thus, even with a boatspeed paddlewheel that is off centerline, and a masthead unit which is slightly angled to one side, you will be able to achieve the same boatspeed and apparent wind angle readings on each tack.

1) Sail the boat close hauled with careful attention to the details of trim on one tack. You will want to duplicate the same trim settings on the other tack. You should sail by the telltales or the angle of heel or a method in which you can easily and consistently keep the boat "in the groove". The idea here is to maintain symmetry in the way you are sailing the boat, and to keep the boatspeed and apparent wind angle as stable as possible.

2) Record the boatspeed and apparent wind angle on each tack as often as you can while the boat is in good stable trim. Allow the boatspeed to accelerate and then level off after coming out of a tack. It is important to collect meaningful data from each tack.

CAL Boatspeed Offset Worksheet Example

Average boatspeed on starboard tack: a______ 6.40

Average boatspeed on port tack: b______ 6.80

Average boatspeed: (a+b)/2 =c______ 6.60

Half difference boatspeed: (a-b)/2 =d______ -0.20

Present Cal Boatspeed Offset reading: e______ 0.010

Set new Cal Boatspeed Offset reading: (If Stbd tack faster, Cal should increase; If Port tack faster, Cal should decrease) (d/c)+e =f______ -0.020

CAL Wind Angle Offset Worksheet Example

Average apparent wind angle on stbd tack a______ 30

Average apparent wind angle on port tack NOTE: readings on port tack are negative. b–_____ -22

Half difference apparent wind angle (a+b)/2=c______ 4

Present Cal Wind angle Offset reading d______ 1.5

Set new Cal Wind angle Offset: (If Stbd tack wider, Cal should decrease; If Port tack wider, Cal should increase) d-c =e______ -2.5

Wind Direction: The Primary Goal

The primary objective of devoting the time to calibrate your instrument system is to develop an accurate Wind Direction solution. The ability to recognize small shifts in Wind Direction on all points of sail is a terrifically powerful enhancement to your tactics and strategy on the race course. This capability is produced by the integration of the information in your Ockam instrument system: boatspeed, apparent wind speed, apparent wind angle, and heading. Because the Wind Direction solution is dependent on the accuracy of these inputs, it follows that if the Wind Direction solution is accurate, the individual inputs (boatspeed, apparent wind speed, apparent wind angle, and heading) will necessarily be accurate. How do you know if your Wind Direction solution is accurate? The most straightforward way to check the accuracy of the solution is to sail upwind and downwind, tacking (and jibing) from port

to starboard tack, looking for a shift in the Wind Direction each time you tack or jibe. In a well cali-brated instrument system the Wind Direction will not change through a series of tacks or jibes.

Setting CAL Windspeed & CAL Upwash

Thus far you have set the majority of the calibrations in the system, which provide the "coarse" tuning of the system. The last two, Cal Windspeed and Cal Upwash, are very powerful calibra-tions which have substantial effect on the Wind Direction solution. This makes these two calibra-tions very effective in fine tuning the Wind Direction solution and allows further tweaking for differ-ent wind strengths.

• Check that QuikCal is set to zero both Upwind and Downwind! You can do

this in the matrix display under the Calibration page in the LIFT/HEADER calibration page. There is a L/H calibration for upwind < 90 degrees TWA and and downwind > than 90 degrees TWA. Make sure the is aiming in those parameters in order to check.

• Get warmed up by sailing upwind and rechecking your work on the boatspeed and apparent wind angle offsets. Besides confirming your previous efforts, this exercise will hone your senses for the real excitement.

• Then tack or jibe back and forth at the appropriate apparent wind angle. The important idea here is to steady the course of the boat down once you are close to the required apparent wind angle. The wind angle is not as important as good data achieved by a steady compass heading.

• On you feel that the Wind Direction has settled in, record the data. Then tack or jibe over to the other board, and reestablish a steady course.

• With plenty of Wind Direction data, at least 6 to 8 sets, you can calculate the change in the calibration.

• Finally, sail back upwind using the same care to develop symmetry in sail settings and steer-ing technique. Concentrate on "groove" sailing, not "scalloping", to enhance your data col-lection.

CAL Windspeed (Downwind Calibration)

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(if too high, it heads)

Downwind, AW speed cal rules

Port Gybe Stbd Gybe

If Headed Downwind, Cal AW Speed Down! This calibration equates boatspeed to wind speed, so it’s done before upwash. Cal Windspeed has the greatest effect on Wind Direction when the Apparent Wind Angle is 90°, which means that you should take data while jibing back and forth to a beam reach as shown above. CAL Windspeed Worksheet Example

Sail downwind at apparent wind angles of about 90°. Stbd Jibe Port Jibe Stbd Port Record WIND DIRECTION on both jibes. Run #1 _______ _______ 230 220 Run #2 _______ _______ 231 221 Run #3 _______ _______ 230 220 Run #4 _______ _______ 232 222 Run #5 _______ _______ 231 221

Average WIND DIRECTION on each jibe a______ b______ 231 221

WIND DIRECTION Difference a-b=c______ 10

Figure change to Cal Windspeed If Direction HEADS you when you jibe, DECREASE Cal Windspeed If Direction LIFTS you when you jibe(example), INCREASE Cal Windspeed Change Cal approximately 1.25% per degree of change in Wind Direction. (0.0125•c)+1=d______ 1.125

Present Cal Windspeed e______ 1.02

Set new Cal Windspeed d•e=f______ 1.15

CAL Upwash (Upwind True Wind Direction Calibration)

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Upwind, AW angle rules

Port Tack Stbd Tack

If Headed Upwind, Cal Upwash Up

Cal Upwash has its greatest effect on Wind Direction when the apparent wind angle is approxi-mately 30°, which means that you should take data while tacking back and forth upwind. CAL Upwash Worksheet Example

Sail upwind and record WIND DIRECTION on both tacks. Stbd tack Port tack Stbd Port Run #1 _______ _______ 230 220 Run #2 _______ _______ 231 221 Run #3 _______ _______ 230 220 Run #4 _______ _______ 232 222 Run #5 _______ _______ 231 221

Average WIND DIRECTION on each tack a______ b______ 231 221

WIND DIRECTION Difference a-b=c______ 10

Figure change to Cal Upwash If Direction HEADS you when you tack, INCREASE Cal Upwash If Direction LIFTS you when you tack (example), DECREASE Cal Upwash Change Cal approximately 0.3° per degree of change in Wind Direction Note sign of (d) is opposite to (c) -0.3•c=d______ -3.0

Present Cal Upwash e______ +0.5

Set new Cal Upwash d+e=f______ -2.5

QuikCal® correction

This is a calibration that adds or subtracts from the magnitude of the true wind angle. If the true wind angle is too narrow (too small in magnigude), wind direction will head when you tack. If it’s too wide (too large in magnitude), you will be lifted when you tack. QuikCal adds or subtracts an adjustable number of degrees from the magnitude of the true wind angle; for a positive 2.0 QuikCal, 21 degrees becomes 23, and –21 degrees becomes -23. QuikCal uses the “Controller card” model; the operator presses an “UnLift” or “UnHead” button on a controller card (or Matryx cal page) to change a variable that directly widens or narrows true wind angle. So if you find yourself being headed, press the “UnHead” button and vice versa. There are separate upwind and downwind corrections. If you wish make a correction, make sure the boat is headed in the right direction. Head upwind to make a correction to your upwind numbers and downwind to correct the downwind numbers.

Make sure that you zero out the QuickCal settings for upwind and downwind at the end of each day so that they don’t affect your wind angles the next time you sail.

Calibration Worksheets CAL Boatspeed Offset Worksheet Example

Average boatspeed on starboard tack: a______ 6.40

Average boatspeed on port tack: b______ 6.80

Average boatspeed: (a+b)/2 =c______ 6.60

Half difference boatspeed: (a-b)/2 =d______ -0.20

Present Cal Boatspeed Offset reading: e______ 0.010

Set new Cal Boatspeed Offset reading: (If Stbd tack faster, Cal should increase; If Port tack faster, Cal should decrease) (d/c)+e =f______ -0.020

CAL Wind Angle Offset Worksheet Example

Average apparent wind angle on stbd tack a______ 30

Average apparent wind angle on port tack NOTE: readings on port tack are negative. b–_____ -22

Half difference apparent wind angle (a+b)/2=c______ 4

Present Cal Wind angle Offset reading d______ 1.5

Set new Cal Wind angle Offset: (If Stbd tack wider, Cal should decrease; If Port tack wider, Cal should increase) d-c =e______ -2.5

CAL Boatspeed Master Worksheet Example

Find a known course at least 1 mile long. Course distance = a______ 1.05

Run measured mile at slack tide and no wind. Out run Back run Out Back Make sure the boatspeed is steady before you begin. Record the measured distance from the Trip Log. Run #1 _______ _______ 0.99 1.03 Run #2 _______ _______ 0.97 1.01 Run #3 _______ _______ 1.01 1.05

Average of the runs b______ c______ 0.99 1.03

Average distance on all runs (b+c)/2 =d______ 1.01

Boatspeed correction a/d=e______ 1.04

Present Cal Boatspeed Master reading f______ 1.01

Set new Cal Boatspeed Master reading e•f=g______ 1.05

CAL Windspeed Worksheet Example

Sail downwind at apparent wind angles of about 90°. Stbd Jibe Port Jibe Stbd Port Record WIND DIRECTION on both jibes. Run #1 _______ _______ 230 220 Run #2 _______ _______ 231 221 Run #3 _______ _______ 230 220 Run #4 _______ _______ 232 222 Run #5 _______ _______ 231 221

Average WIND DIRECTION on each jibe a______ b______ 231 221

WIND DIRECTION Difference a-b=c______ 10

Figure change to Cal Windspeed If Direction HEADS you when you jibe, DECREASE Cal Windspeed If Direction LIFTS you when you jibe(example), INCREASE Cal Windspeed Change Cal approximately 1.25% per degree of change in Wind Direction. (0.0125•c)+1=d______ 1.125

Present Cal Windspeed e______ 1.02

Set new Cal Windspeed d•e=f______ 1.15

CAL Upwash Worksheet Example

Sail upwind and record WIND DIRECTION on both tacks. Stbd tack Port tack Stbd Port Run #1 _______ _______ 230 220 Run #2 _______ _______ 231 221 Run #3 _______ _______ 230 220 Run #4 _______ _______ 232 222 Run #5 _______ _______ 231 221

Average WIND DIRECTION on each tack a______ b______ 231 221

WIND DIRECTION Difference a-b=c______ 10

Figure change to Cal Upwash If Direction HEADS you when you tack, INCREASE Cal Upwash If Direction LIFTS you when you tack (example), DECREASE Cal Upwash Change Cal approximately 0.3° per degree of change in Wind Direction Note sign of (d) is opposite to (c) -0.3•c=d______ -3.0

Present Cal Upwash e______ +0.5

Set new Cal Upwash d+e=f______ -2.5

NYYC 42 Polars & Targets Ockam has worked very hard in conjunction with Frers Design to develop a solid set of polars for the NYYC 42 by logging data utilizing OckamSoft 4 and Expedition software packages. We have continued to refine the upwind and downwind targets for the boat. Each Ockam Tryad Processor comes preloaded with the latest NYYC42 Polar file. The Ockam polar file utilizes approximately 2000 data points. This allows for the smoothest possible polar curve. Polars are always a work in progress, and we will endeavor to keep you updated with the latest polars for the Swan 42. You can also utilize the tools in Expedition tactical navigation software to further refine your own polar file.

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Matryx Quick Reference Guide The following is a step by step guide to understanding the functionality and control of the Matryx display.

UPWIND DOWNWIND

TWS VS TWA VMG TWS VS TWA VMG

4 4.33 41.2 3.26 4 4.33 138.6 3.25

6 5.85 39.9 4.49 6 6.41 138.0 4.76

8 6.81 37.7 5.39 8 7.14 145.6 5.89

10 7.18 36.5 5.77 10 7.62 151.0 6.66

12 7.38 35.7 6.00 12 8.12 154.1 7.3

14 7.50 35.8 6.08 14 8.57 156.6 7.87

16 7.59 36.4 6.11 16 9.27 152.0 8.18

18 7.67 37.1 6.12 18 10.84 146.0 8.98

20 7.72 37.6 6.12 20 12.01 145.6 9.91

22 7.74 37.9 6.11 22 12.84 147.8 10.87

24 7.73 38.1 6.09 24 13.79 149.7 11.91