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ESSENTIAL GUIDE
Zeus - Sailing Navigation
ZEUS SAILING NAVIGATION SYSTEM
Passionate about sailing
For over a half-century, B&G systems have been the favored choice of passionate sailors for extremes in navigation performance and reliability. B&G continues to provide only the best electronics available for cruising or racing, with a product focus designed specifically for sailors. Count on B&G for instruments, sailing autopilots, chartplotters, radar and integrated systems when your success and safety counts. B&G has been the undisputed world leader in sailing instrumentation since 1956, when the company was founded by avid yachters Major R. N. Gatehouse and Ronald Brookes, to develop and manufacture performance navigation electronics for cruising and racing sailing yachts.
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ZEUS SAILING NAVIGATION SYSTEM
The new Zeus range
B&G’s new Zeus range is the first multifunction navigation system designed specifically for sailing. Zeus provides sailors with easy access to features for sailing navigation and allows total control of navigation on-board. At the core of the B&G Zeus system is a highspecification multifunction display, combining powerful processing along with a very high-quality, sunlight-viewable, screen. The Zeus display – available in 8” or 12” screens – allows rapid access to a wide range of features. A combination of a great user interface with direct access keys, alphanumeric keypad and rotary dial ensures features can be controlled in a quick and straightforward fashion.
Compatibility The power of Zeus is available to all, compatible with most instrument systems via the industry standard NMEA 0183 and NMEA 2000® protocols. See the B&G website for connection examples: www.bandg.com. B&G H3000 Hercules systems can connect via the H-Link USB connection which gives additional functionality including accessing calibration data on the H3000, displaying more advanced functions. Hercules Performance and Hercules Motion users can also view, edit and save their Polar Tables.
AWARD WINNING TECHNOLOGY
B&G Zeus receives Sail Magazine's 2011 Freeman K. Pittman Innovation Award.
Broadband 3G™ Radar awarded “Best on Test” from Practical Boat Owner Magazine.
B&G Zeus wins NMMA Innovation Award at the Miami Boat Show 2011.
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ZEUS SAILING NAVIGATION SYSTEM
Key features: Chart plotting • Clear presentation of integrated regional premium cartography • Sail navigation overlay • Supports additional cartography from Navionics® • 2D/3D, terrain shading and photo overlay options.
Weather • GRIB weather forecast display • Sirius® Weather (US only).
Radar • Exceptionally clear radar PPI display • Chart overlay mode • Broadband Radar™ compatible. Providing low power use and InstantOnTM
Instruments • Instrument data displays, user configurable • TimePlot and WindPlot trending charts • H3000 instrument integration via H-Link • Compatible with most NMEA 0183 and NMEA 2000® systems.
System Integration • CZone™ distributed power system compatible • SonicHub™ multimedia system compatible • AIS display • StructureScan™ sonar imaging – picture what’s below • Autopilot control.* * Selected autopilots only
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ZEUS SAILING NAVIGATION SYSTEM
Weather What does the weather overlay do? The unique weather functionality of the B&G Zeus allows the user to view forecast data overlaid on the chart for a clearer understanding of the conditions they are likely to face.
Features • Display of Wind Speed and Direction • Display of Barometric Pressure with isobars and pressure centre indicators (High or Low)
B&G Zeus supports two forms of weather data; GRIB files, which can be downloaded for any location in the world, and the Sirius® Marine Weather Service, available only in the continental US.
• Manual time step control – select any available forecast time • Animation option shows how weather systems are likely to develop and allows the sailor to take appropriate steps to prepare, or route around • Cursor Info feature allows quick assessment of the forecast at a particular location and time.
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ZEUS SAILING NAVIGATION SYSTEM
What are GRIB files?
What is Sirius® weather
GRIB files are the format used by the world’s meteorological organizations to store and exchange forecast data. Some organizations (such as the US National Weather Service) make their data available for general use.
When connected to a Navico Weather Module (WM-2), you can subscribe to and include the Sirius Marine Weather Service on your Zeus system.
Most free sources of GRIB data use the US General Forecast System (GFS) to provide the end user with a regional subset of the global forecast. The standard resolution of GFS data is 0.5° with forecast time intervals of 3 hours. The duration of the forecast depends on the source of your GRIB files, but tends to range from 3 to 7 days. It is important to note that most free GRIB files are raw outputs from numeric computer models, if very high quality data is required, then subscription services that either run higher resolution local models, or have additional processing by meteorologists are available.
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The Sirius weather service covers inland US waters and coastal areas into the Atlantic and Pacific Oceans, Gulf of Mexico and Caribbean Sea. The weather products received vary depending on your selected subscription package. Sirius also provides satellite radio services that integrate with the SonicHub™ audio server. For more information: www.siriusxm.com/marineweather
ZEUS SAILING NAVIGATION SYSTEM
Viewing Forecasts What can I see? Information at cursor • Position • Range & Bearing to Cursor • Wind Speed (Kn) • Wind Direction (ºM) • Barometric Pressure (mb) • Time of displayed forecast • Time from start of forecast file (+39 hours).
Weather overlay
Animation controls
• Wind barbs show the direction and speed of the wind forecasted
• Time control for manual stepping through GRIB data
• Isobars indicate barometric pressure. High and Low pressure centers are identified.
• Speed control for animation of GRIB file at low, medium and high speed.
A GRIB file contains forecast information for a set number of days. It is possible to animate the weather data which shows how weather systems are developing. The speed dial allows the user to set the speed at which the Zeus unit will animate the GRIB file – time steps and duration vary depending on the source of your GRIB file. Along with the automated animation, you can use the time dial to step through the file manually, viewing the forecast for a specific date and time. As you move the cursor around the chart you will see the wind speed, wind direction and barometric pressure values at the cursor point for the current forecast time selected. The angle of the wind barb indicates the geographical wind direction from 0 to 359 degrees. Wind speed is
indicated by a combination of short barbs, long barbs and pennants at the end of the wind tail. See below. SYMBOLS EXPLAINED Zero knots / Indeterminate Wind Direction
Wind direction
1 x Short Barb = 5 knots
Wind direction
1 x Long Barb = 10 knots
Wind direction
1 x Pennant = 50 knots
Wind direction
2 x Long Barbs, 1 x Short Barb = 25 knots
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ZEUS SAILING NAVIGATION SYSTEM
Using GRIB files Where can I get GRIB files? GRIB files are widely available, and most standard-resolution data is free to the user with the exception of communication costs. There are three basic ways to acquire a GRIB file; different methods are used by each provider: • Website. Straightforward area list or interactive map tool to download the region you require •
E-mail services. Developed to be very efficient on data use. The user sends an e-mail that contains specific codes for the data they require and receive an e-mail with GRIB file attachment in return – useful for smartphone use
UGrib Software
•
PC-based client programs. These usually work in a very similar way to a browser based tool, but with the the program installed there is less to download (only the GRIB file itself ) so it's faster and saves on communication costs. Some client programs also include a compression tool to further save on data cost.
zyGrib Software
Free GRIB Sources Source
Wind Speed
Wind Direction
Surface Pressure
Max Resolution
Forecast period (days)
Other features
grib.us
Yes
Yes
Yes
0.5º
3,5,7
Website or PC Client software. Includes file compression and max file size tools for low bandwidth applications
saildocs.com
Yes
Yes
Yes
1.0º
15 (max)
E-mail request service – originally designed for low bandwidth applications – can be used from smartphones
mailsail.com
Yes
Yes
Yes
1.0º
3
zygrib.org
Yes
Yes
Yes
0.5º
3 *Correct at time of printing
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ZEUS SAILING NAVIGATION SYSTEM
Higher resolution GRIB forecasts are available and are usually subscription-based services. Data is generally from a very high resolution localized model and/or has been subjected to some form of post-processing of the raw GRIB data.
High Resolution GRIB Sources Source
Wind Speed
Wind Direction
Surface Pressure
Max Resolution
Forecast period (days)
Other features
predictwind.com
Yes
Yes
Yes
0.01º
1,3,5
Requires client software – available from PredictWind
theyr.com
Yes
Yes
Yes
0.02º
1,3,6
Also supply free 0.5º GRIB data *Correct at time of printiing
Loading GRIB files onto Zeus Up-to-date GRIB weather files are easily loaded via a quick and simple process. • Download a file from your chosen source, save it to a USB stick
• Copy the file to Zeus via the Files option under Pages • File transfer is also possible via Memory Card.
• Insert the USB stick containing the file into the USB port on the front of the Zeus unit
Transfer with a USB stick
Smartphone transfer
USER TIP Many modern smartphones can receive GRIB files via email, or by using their web browser, and save them to the phone memory. In many cases the phone will act as a USB drive when connected to the B&G Zeus.
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ZEUS SAILING NAVIGATION SYSTEM
Sailing Overlay What does the Sailing Overlay do? B&G’s Zeus is the first and only chartplotter developed specifically for sailing. The unique Sailing Overlay allows the display of navigation information designed to aid the sailor in determining the tidal effects on the boat and the best position to tack or gybe to reach a waypoint or clear a headland. Data displayed in the Sailing Overlay includes: • Through-Water and Over-Ground vectors show the effect of tide and leeway on your course •
Mark and Boat Laylines, which help the skipper easily assess whether the boat will be able to clear a headland or obstacle on its next tack. Laylines can be corrected for tidal flow
•
Recent min/max layline positions allow the navigator to make a safe decision to tack for a headland or waypoint in shifting winds, based on the recent variation in wind direction
• Time and distance to layline information is provided for each tack, allowing preparation time for maneuvers.
USER TIP Are you always being asked, “how long until we tack?” Display “Time To Layline” in the data bar so you can always know the answer to the question.
What other information is available? The data bar at the top of the chart screen can be configured by the user, allowing the selection of any Zeus system data. As part of the process for displaying the laylines, information regarding time and distance to the layline is calculated. This information can be displayed in the 10
data bar, and prove invaluable when asked “how long until we need to tack?” or if you wish to stay a certain distance from the coastline The Heading Extension line allows the user to see if they are achieving the Target True Wind Angle.
ZEUS SAILING NAVIGATION SYSTEM
What are laylines?
How do laylines work?
In simple terms, laylines represent the most efficient way of reaching your destination, given the present wind conditions – by sailing along your target laylines you can maximize your Velocity Made Good (VMG).
Laylines are based on the True Wind Direction (TWD) from your instrument system along with either (1) your target upwind and downwind sailing angles or (2) your actual sailing angles.
• “Mark Laylines” display the target course to sail to reach the destination
Target angles provide you with the most efficient sailing angle, while actual angles use real data from the live measurements.
• “Boat Laylines” display the target course of the yacht The point where the two sets of laylines intersect can be thought of as the tack (or gybe) point. Zeus also offers the ability to correct laylines for the effects of the current tide measurement.
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Targets are set by either entering your upwind and downwind sailing angles into Zeus, or automatically from a Polar Table-equipped H3000 system (Hercules Performance or Hercules Motion)
• Actual data uses your current True Wind Angle
What can I see? Boat vectors (blue line)
Mark laylines (solid line)
• Vectors show predicted position of boat at a future time
• Indicate tacking point to make the waypoint
• User-set based on distance or time •
Select from Water vector (Heading/Boat Speed), Ground vector (COG/SOG) or both – allowing the navigator to assess tidal effects
Boat laylines (solid lines) • Starboard (Green) and Port (Red) tack •
• Tidal correction available
Min/Max laylines (dashed lines) •
Indicates the best- and worst- case layline positions recorded in recent data (manual user reset available)
•
Allows the navigator to make an informed decision on a “safe” or “risky” call to tack on a layline
Laylines use Manual, Actual or Polar Targets (H3000 Hercules Performance or Motion only)
• Tidal correction available
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ZEUS SAILING NAVIGATION SYSTEM
Zeus provides the user with three options: MANUAL LAYLINES
ACTUAL LAYLINES
POLAR LAYLINES
Should be selected if you do not have an instrument system that can send Polar target information to the Zeus system but you want to sail to a target wind angle. Manual Laylines allow the user to preset the upwind and downwind sailing angles for the boat. Target angles vary by boat and conditions, but angles of 45º upwind and 165º downwind are a good starting point.
Are incredibly useful for cruising yachts, where the focus is more on tacking in the right place to clear obstructions to stay safe rather than sailing at optimum performance all the time. In this mode the laylines are calculated from the current True Wind Angle, either directly from the instrument system (if available) or calculated from Boat Speed and Apparent Wind Angle. This setting gives you a realistic tacking angle based on your current performance.
Are based on the upwind and downwind Target True Wind Angle from the Polar table stored in compatible instruments. It is also possible to display the Target True Wind Angle in the data bar. All types of laylines can be corrected for tidal flow.
Tidal Correction Zeus offers the user the ability to correct the laylines for tidal effects. Unlike PC-based chartplotters, which often use tidal models to predict tidal effects along your entire route, the B&G Zeus uses the live instrument data to calculate the tidal effect on the boat, and applies this information to the laylines. This means the user does not have to worry about updating the tidal model.
2.12kts = Current Rate and Direction
9kts
7kts
In the screenshot at right, we can see the difference between laylines with tidal correction applied, and those without tidal correction applied. In this example we can see the boat's “through the water” performance and compare it with its “over the ground” performance to calculate the measured tide rate and direction.
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Boat Speed
9kts
Heading
042°M
SOG
7kts
COG
047°M
Tide Rate
2.12kts
Tide Direction
239°M
ZEUS SAILING NAVIGATION SYSTEM
If the yacht is tacked according to the laylines in image 1, it would not make the waypoint, due to the adverse tide – at least two more tacks would be required. In image 2 we can see that the laylines have become wider to account for the tide; tacking on these laylines will help ensure the yacht makes the mark.
1. Laylines without tidal correction
Heading, Leeway and Course Heading is the direction that the yacht is pointing as you sail through the water. This is not always the actual direction you're travelling through the water – due to leeway. Leeway is the angle that the boat slips sideways, relative to the direction it is pointing.
2. Laylines with tidal correction
USER TIP In addition to tide, remember that windshifts will affect your ability to make waypoints, familiarize yourself with the limit layline feature to judge how likely a windshift is to prevent you from making your waypoint.
We refer to the angle that we actually travel through the water (heading + leeway) as “Course”. Course does not include any tidal effects as it is measured relative to the water. The difference between Course and Course Over Ground is caused by tides or currents. On advanced instrument systems, like the B&G H3000, it is possible to calculate Leeway and correct the wind data for this value. On less advanced systems the leeway value is not available so calculation is based only on Heading.
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ZEUS SAILING NAVIGATION SYSTEM
Time Plots What is a Time Plot? Time plots allow you to graph the data that is being sent to your B&G Zeus from the instrument system. There are two standard layouts for Time Plots in Zeus:
What is a Wind Plot?
• Layout 1 displays 4 Time Plots alongside the Wind Plot (Boat Speed, AWA, TWA)
A Wind Plot is a special type of Time Plot specifically designed to help you understand recent changes in wind speed and direction, generally referred to as wind trend. While normal Time Plots display horizontally, Wind Plots are configured vertically with the newest data being displayed at the top of the screen.
• Layout 2 displays 3 Time Plots alongside the Wind Plot (Depth, TWA, Boat Speed, VMG to Waypoint) The user can change between layout 1 and 2 and edit the data in each layout.
USER TIP Look for correlations between changes in wind speed and changes in wind direction - if you know that an increase in wind leads to a 10 degree windshift you can prepare for it.
What can I see? Historical data (green line) • The green line plots the data from the instrument system • The user can select which data to display
Time periods • For each Time Plot or Wind Plot the user can set the time period shown • Default period is 10 minutes • User options are 5, 10, 30 and 60 minutes • Barometric pressure up to 48 hours
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By showing the data in this format Wind Plots show changes in wind direction in an intuitive way – if the wind is shifting to the right, so is the graph. Alongside the wind direction is the wind speed, this enables you to correlate the changes in direction and speed – does the wind tend to shift to the right in gusts? Here you can see.
B&G ZEUS
THE ONLY CHARTPLOTTER DESIGNED FOR SAILING… View and predict vital weather information. Port and Starboard colored Laylines indicate when to safely tack or gybe. Water and ground vectors show the effects of tide and leeway. Makes your B&G instruments quick and easy to calibrate. Also compatible with other instrument systems.
Find out more at www.bandg.com/zeus
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www.bandg.com
Products, features and specifications are the most recent available and are subject to change without notice. No liability can be accepted for errors or omissions in this document. Navico, Inc. | 12000 East Skelly Drive | Tulsa, OK 74128-2486 | USA Š 2011 Navico 1109 985-10403-001 A brand by Navico – Leader in Marine Electronics