Shearwater TERN Operating Instructions Manual
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Shearwater TERN Operating Instructions Manual

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  • Page 1: Table Of Contents

    Operating Instructions...

  • Page 2: Table Of Contents

    11�6� General ��������������������������������������������������������������������������������������������59 3�5� Info Screens ������������������������������������������������������������������������������������16 12� Firmware Update and Log Download ������ 60 3�6� Info Screen Descriptions ����������������������������������������������������������� 17 12�1� Shearwater Cloud Desktop ���������������������������������������������������� 60 3�7� Home Screen Customization ��������������������������������������������������� 21 12�2� Shearwater Cloud Mobile ���������������������������������������������������������62 3�8� Alerts������������������������������������������������������������������������������������������������ 23 13�...

  • Page 3: Conventions Used In This Manual

    Information boxes contain useful tips requirements. Dives requiring staged decompression are substantially for getting the most out of your Tern� more risky than dives that stay well within no-stop limits. Diving with rebreathers and/or diving mixed gases and/or performing...

  • Page 4: Introduction

    • Bluetooth Dive log uploading to Shearwater Cloud • Free firmware updates 1. Introduction The Shearwater Tern is a dive computer for beginner to expert divers� Please take the time to read this manual� Your safety may depend on your ability to read and understand the Tern displays�...

  • Page 5: 1�1� Notes On This Manual

    If you are unsure, consult the appropriate section of the Some features of the Tern only apply to certain dive modes. Look manual for reference� for the corresponding mode icons throughout the manual to help distinguish which features are available in the various modes.

  • Page 6: 2� Basic Operation

    1 mbar of pressure corresponds to approximately To turn the Tern On, press any button� 1 cm (0�4”) of water� So, when at sea level, the Tern will automatically power on and enter dive mode when about 0�9 m (3 ft) underwater�...

  • Page 7: 2�2� Buttons

    Operating Instructions 2.2. Buttons Button Hints When in a menu, button hints label each button: All Tern operations are simple single button presses� SELECT LIGHT FUNC (Upper Left) (Upper Right) Dive Watch Tools Deco DOWN HOME Deco Model MENU INFO...

  • Page 8: 2�3� Changing Between Modes

    To change from Dive that makes accessing Mode to Watch Mode, your most used press the Menu button functions on the Tern a and select Watch from little easier� DECO the main menu� 20 2 The function button...

  • Page 9: 3� Dive Mode Interface

    3.1. Default Dive Setup type of diving� The Tern comes pre-configured for recreational diving� Designed for use during recreational, air only, no-decompression diving activities� The default dive mode for the Tern is a simple Air only mode� • Simple Set-up •...

  • Page 10: 3�3� Main Screen Layout

    Operating Instructions 3.3. Main Screen Layout Standard layout The Tern has two different screen layouts available in Top Row every dive mode, Big and Standard� Depth, Mode & Ascent Rate Change the Screen layout from the Dive Settings Menu� See details on page 48�...

  • Page 11: 3�4� Detailed Descriptions

    Operating Instructions Freedive Mode Ascent / Descent Rate Display 3.4. Detailed Descriptions Freedivers ascend much faster than SCUBA divers� So, ascent rate in Freedive Mode is measured in feet per second (fps) or meters per second (mps) rather than The Top Row feet per minute or meters per minute�...
  • Page 12 Important! that stop� O2/He All decompression information including By default the Tern uses a 3m (10ft) last deco stop Deco Stops, NDL, and Time to surface are depth� When in decompression, you may perform predictions that assume: your last deco stop deeper if you wish - deco calculations will remain accurate�...
  • Page 13 Operating Instructions The Info Row Active Gas By default, the left position in the Standard layout 27 1 The Info row is the center row in the Big layout shows the currently selected breathing gas� and the third row in the Standard layout� Info row information is customizable�...
  • Page 14 Operating Instructions 103.6 4:57 The Bottom Row Alternate Active Gas Location : 18 When the info row is not displaying the active breathing gas, this value is displayed in the bottom row at the very bottom of the computer display� Notification Setting Icon Bottom Row, AIR Mode on a dive Indicates what notifications are turned on�...

  • Page 15: 3�5� Info Screens

    Press the INFO button Note that although these screens are generally (bottom right), to step representative of the Tern display, info screen content through Info Screens varies for each mode� For example, decompression related info screens are not available in gauge mode�...

  • Page 16: 3�6� Info Screen Descriptions

    Operating Instructions CNS Toxicity Percentage 3.6. Info Screen Descriptions Central Nervous System oxygen PPO2 toxicity loading percentage� Turns 1.02 when greater than 100%� Last Dive Info SURFACE The CNS percentage is calculated LAST DIVE PPO2 continuously, even when on the 30.7 26:57 surface and turned off�...
  • Page 17 PPO2 is still correct� stops� The surface pressure is set based on the lowest pressure the Tern sees in the 10 minutes prior to the start of a dive� Therefore, altitude is automatically accounted for and no special altitude setting is required�...
  • Page 18 Operating Instructions Time TIME In a 12 or 24 hour format� Time 2:31 2:46 format can be changed in the watch settings menu� SURFACE End of Dive Time (EOD) This is similar to TTS but is 2:46 expressed as a time of day� SURFACE The time of day at which you can expect to surface if you...
  • Page 19 Operating Instructions Tissues Bar Graph Sample Tissue Bar Graphs TISSUES TISSUES SURFACE The tissues bar graph shows the tissue compartment SURFACE inert gas tissue tensions based on the Bühlmann ZHL- On surface (sat� with air) 16C model� Note: Gas is 79% N (21% O , or Air) The fastest tissue compartment is shown on the top,...

  • Page 20: 3�7� Home Screen Customization

    Operating Instructions 3.7. Home Screen Customization Home Screen Customization Options In the Standard layout, the Home screen (first page) Option Info Display Option Info Display 27 1 Info Row is customizable with 1, 2 or 3 items� TIME PPO2 2:31 2:46 Current Gas Time of Day...
  • Page 21 Operating Instructions Home screen only info displays Gas Density Display Some advanced info displays are only available as Density PPO2 The current gas density based on custom home screen options and not in the info rows� the current active gas and ambient pressure�...

  • Page 22: 3�8� Alerts

    Alert the user to system errors� Doesn't flash� Errors represent unexpected O2/He PPO2 ERROR 21/00 system behavior� Contact Critical alerts flash between inverted and Upgrade Fail Shearwater if you experience normal text� SURFACE a system error� Alert Alert Flashes Page 22 Doc. 15301-RevB (2023-11-24)
  • Page 23 Electromechanical devices can and will eventually fail� Vibration Alerts In addition to visual notifications, the Tern has vibration Always be proactively aware of your depth, alerts to help quickly notify the diver of warnings, no-decompression limit, gas supply, and errors and dive events�...

  • Page 24: 4� Safety And Decompression Stops

    Settings� If you ascend to the surface before the safety The Tern does not do “deep safety stops”� That is, stop countdown finishes, the safety stop will there are no extra stops added around 15m to 18m appear paused, but this will disappear once (50ft to 60ft) when ascending from a no-deco dive�...

  • Page 25: 4�2� Decompression Stops

    Big layout� the decompression scheduled was violated, to allow you to make decisions based on your On the Tern, the deco stop label appears in training� because a deco obligation is an emergency condition in recreational diving�...

  • Page 26: 5� Decompression And Gradient Factors

    Operating Instructions 5. Decompression and Gradient Graph from Erik Baker’s “Clearing Up The Confusion About Deep Stops” Pressure Graph: Gradient Factors Factors 100% 80% 60% 40% 20% 0% The basic decompression algorithm used by this computer is Bühlmann ZHL-16C� It has been modified M-value by the use of Gradient Factors that were developed Gradient...

  • Page 27: 5�1� Decompression Information Accuracy

    Operating Instructions 5.1. Decompression Information Example: A diver on a decompression dive to 40m/131ft for 40 minutes with GF settings of 45/85 Accuracy has two gases programmed into their computer and turned on: 21% & 99%� The diver’s decompression Decompression information displayed by this schedule will be calculated based on breathing 21% computer, including NDL, stop depth, stop time, and oxygen for the descent, bottom and ascent phases...

  • Page 28: 6� Example Dives

    Operating Instructions 6. Example Dives 6.1. AIR mode Example Dive 29.6 This is an example of displays that might be seen on a : 26 SURFACE simple no-decompression dive in AIR Mode using the Big layout configuration� 1� Pre-Dive - This is the surface screen immediately 1�...

  • Page 29: 6�2� 3 Gasnx Mode Example

    Operating Instructions 6.2. 3 GasNx mode Example Deco Edit Gases Deco Model This is an example of displays that might be seen on a ZHL16C+GF multi-gas decompression dive in 3GasNX Mode� GF Conserv. High 45/80 Max Depth: 40 meters Bottom Gas: 21% O Last Stop Bottom Time: 20 minutes Deco Gas: 50% O , 99% O...
  • Page 30 Operating Instructions 3 GasNx mode Example (cont.) 6� Max depth - Once NDL hits 0, deco stops will be DECO DECO DECO 12 1 needed� Stop requirements display in place of the NDL� TTS has increased to include deco stop time� PPO2 PPO2 1.03...

  • Page 31: 6�3� Gauge Mode

    Operating Instructions 6.3. Gauge Mode Gauge Mode turns the Tern into a simple depth and time display (a�k�a� a bottom timer)� Since decompression tissues are not tracked in Gauge Mode, changing to or from Gauge Mode resets the STOPWATCH deco tissues�...

  • Page 32: 7� Freedive Mode

    7. Freedive Mode 7.1. Default Freediving Layout By default, Freedive Mode uses the Big layout� It shares Freedive Mode optimizes the Tern for freediving� most features with the other dive modes but has a few unique characteristics� Although many of the basic functions of the computer are the same as in other dive modes, Freedive Mode •...

  • Page 33: 7�2� Freediving Info Screens

    NOW mBar SURF 4943 1013 The Tern supports 3 independently customizable SURFACE sets� For each set, the user can customize the alerts activated during a dive as well as a handful of settings TIME...
  • Page 34 Operating Instructions Freediving Alerts Time Alerts: Customizable in each set, these alerts are useful for Notify Time, Warn Time, Max Time, and Surf Time all notifying the diver of different phases of a freedive� trigger when time thresholds have been exceeded on a dive or in the case of Surf Time, after the diver has Freediving alerts differ from normal alerts in several been at the surface for a defined amount of time�...

  • Page 35: 8� Dive Tools

    Operating Instructions 8. Dive Tools Freediving Settings: Customizable freediving settings include: • Water Type The Dive Tools can be found in the DECO • Dive Start Depth Select Gas main menu of every dive mode 20 2 • Dive End Depth Dive Tools and can be accessed both at the O2/He...

  • Page 36: 8�3� Test Alerts

    Setup Negative The planner uses the current gases programmed Positive into the Tern in the current dive mode, as well as the Click current GF low/high settings� Use the up and down arrows to select an alert and press select to test it�...
  • Page 37 There are no settings to enter� (RMV is last used value) 1 24 Limitations The Tern Deco Planner is intended for simple dives� Multi-level dives are not supported� The Deco Planner does not provide thorough validation of the profile� For example, it does not check for nitrogen narcosis limitations, gas usage limitations, or CNS percentage violations�...

  • Page 38: 8�5� Ndl Planner

    Operating Instructions 8.5. NDL Planner A Gas Usage screen gives a total gas consumption report and a dive summary screen shows the total dive time, the time spent on deco and final CNS% The No-Decompression Limit after the last page of the decompression schedule� (NDL) Planner is a quick way to determine how much bottom time Next dive...

  • Page 39: 9� Watch Mode

    Operating Instructions 9. Watch Mode 9.2. Watch Tools All of the basic watch In Watch Mode, the Tern’s screen will always remain on features can be found in the for ease of use� Watch Tools menu� The Tern can be configured to automatically turn off to...
  • Page 40 Operating Instructions Timer Stopwatch The Tern’s timer can be edited to count down up to 10 The Stopwatch is universal throughout the Tern� A hours� stopwatch started in Watch Mode will continue in any diving mode until it is stopped�...

  • Page 41: 9�3� Watch Face Colors

    Operating Instructions Flashlight The flashlight simply turns the Tern screen on full brightness to provide an emergency source of light� It Analog is only useful in the darkest of rooms or caves� Watch Faces DECO DECO DECO Three watch faces are available for the Tern: Analog,...

  • Page 42: 10� Menus

    Alerts Edit FD Set 10.1. Main Menu Edit Gases Dive Tools Alerts Bluetooth Alerts All Tern menus can be accessed Settings from the main menu which can be Bluetooth Bluetooth brought up on any home screen by Settings Home Settings pressing the menu button�...
  • Page 43 Operating Instructions Dive / Watch Select Gas Toggles between the selected Dive Mode and This menu item allows you to pick Watch Mode� a gas from the gases you have DECO Watch created in 3GasNx mode� 30 2 Only available at the Select Gas O2/He Dive...
  • Page 44 Operating Instructions Edit Gases Edit Gas The Edit Gases function allows The Edit Gas menu is only available when in Nitrox you to set up 3 gases When in mode and allows you to set your breathing gas� This 3GasNX mode� menu is available at the surface and while on a dive�...
  • Page 45 Operating Instructions Edit Freedive (FD) Set Regularly test your alerts with the Test Alert Use this menu item to edit the current freedive set� tool described on page 36 to ensure they are working and you can feel them through your exposure suit�...
  • Page 46 Salt or fresh water� This setting affects depth readings because salt water is more dense� Use this menu to set how the DECO Dive Tools 30 2 Tern will notify the user of an Start Depth Alerts alert� The depth threshold for beginning a dive� O2/He...
  • Page 47 End Dive Delay has expire� This logs� is useful if you have set a particularly long End Dive Delay and want to access the surface only features of the Tern quickly following a dive� Page 47 Doc. 15301-RevB (2023-11-24)

  • Page 48: 11� Settings Reference

    When changing to or from Gauge or Freedive Mode, the decompression tissues are cleared� This is because 11.1. Dive Settings Menu when in these modes the Tern does not know what gas you are breathing, and therefore cannot track The first menu item within inert gas loading�...
  • Page 49 Operating Instructions Home screen The Standard layout allows customization of the entire first page of the Info row� This option is used to customize the Info row on the Home screen� Pick the number of elements you would like in the info row, then proceed to select which information you would like displayed in each position�...
  • Page 50 Operating Instructions FUNC Button In dive modes the FUNC button options are: The function button (top right button) can be customized in every mode to act as a shortcut to your FUNC Setting Description most commonly used tool� Edit Gas Opens the Edit Gas Menu Use the FUNC Button menu item in dive settings to choose the function button shortcut�...
  • Page 51 For more information on the different types of alerts see the Alerts section on page 22� Log Rate Sets how often dive samples are added to the Tern’s For a list of alerts you might encounter see Warnings log� More samples will give a higher resolution dive and Information Displays on page 64�...
  • Page 52 Operating Instructions PPO2 Limits OC Deco PPO2 All decompression predictions (Deco schedule and This section allows changing of PPO2 limits� TTS) assume that the gas used for decompression at a given depth will be the gas with the highest PPO2 less than or equal to this value�...

  • Page 53: 11�2� Deco Menu

    Operating Instructions 11.2. Deco Menu A custom GF option is also Deco available in every dive mode� The Deco Settings Menu GF Conserv. When Custom is selected, Settings provides options for adjusting 40/85 fields for editing GF Low and the decompression algorithm� GF Low GF High will appear in the Dive|OC Rec...

  • Page 54: 11�3� Gas / Gases

    Operating Instructions Safety Stops 3 GasNX Deco Settings The Safety Stop setting can The Tern supports 3 be set to the following values: programmable gases in Last Stop Deco|40/85 3GasNX dive mode� • Safety Stop • 3 minutes Gases This setting is the same as Adapt •...

  • Page 55: 11�4� Display

    • Sunlight • Night • Predator Themes apply presets Colors that quickly change the overall look of the Tern user interface� Theme In addition to these preset Sunlight themes, the Tern’s color scheme can be extensively Customize customized� Choose the “Standard”...
  • Page 56 30 s option when the LIGHT button is pressed� • 1 min • 5 min The battery life of the Tern is dramatically improved • 10 min when “Off”� This is a convenient feature if you forget • 20 min your Tern charger at home and are being judicious with battery consumption�...

  • Page 57: 11�5� Watch

    FUNC button options Watch Time The function button has different options that can be independently set for each mode� In Watch Mode, Time on the Tern is set here� General there are eight function button options� Date FUNC Setting Description Date on the Tern is set here�...

  • Page 58: 11�6� General

    Tern, disabling quick charge may help� Defaults This will reset all user changed options to factory settings and / or clear the tissues on the Tern� A reset to defaults cannot be reversed� Note: This will not delete dive logs, or reset dive log numbers�...

  • Page 59: 12� Firmware Update And Log Download

    Connect to Shearwater Cloud Desktop On your Tern, start Bluetooth by selecting the There are two ways to update the firmware on your Bluetooth menu item from the main menu� Tern: 1) With Shearwater Cloud Desktop...
  • Page 60 Operating Instructions Update Firmware Once the Tern is connected, the connect tab will show a picture of the dive computer� Select “Update Firmware” from the connect tab� Shearwater Cloud Desktop will automatically select TERN TX the latest available firmware� The Tern screen will display a progress indicator while receiving the firmware�...

  • Page 61: 12�2� Shearwater Cloud Mobile

    OK� Store� Shearwater Cloud will transfer the Connect to Shearwater Cloud Mobile dives to your smart phone� On your Tern, start Bluetooth by selecting the Bluetooth menu item from the main menu� Update Firmware DECO 30 2 Once the Tern is connected to Shearwater cloud Bluetooth mobile, select “Update Firmware”...

  • Page 62: 13� Tern Strap

    The screen will not turn on during charging to preserve the long term health of the screen and battery, but pressing any button will wake up the Tern so the time can be viewed� The SUN button will adjust the screen brightness and the OFF button will turn the screen off�...
  • Page 63 All settings are retained permanently� No loss of settings occurs if the battery dies� Clock The clock (time and date) data will be lost if the Tern experiences a total loss of power� Once the battery is charged, you will need to update the Clock and Date in the Settings >...

  • Page 64: 15� Troubleshooting

    Please contact STOPWATCH WARNING tissue inert gas loading Plan repetitive dives 103.6 4:57 TISSUES CLEAR Shearwater if you experience any unexpected errors: has been set to default accordingly. SURFACE levels� info@shearwater�com 19:16 Deep Switch to a gas with a...
  • Page 65 Operating Instructions Display Meaning Action to take Deep Decompression stops STOPWATCH WARNING Perform decompression 103.6 4:57 are required� DECO NEEDED stops as directed. SURFACE 19:16 Deep Ascend soon to avoid STOPWATCH WARNING NDL is less than 5 103.6 4:57 decompression obliga- LOW NDL minutes�...

  • Page 66: 16� Storage And Maintenance

    Burn in is more likely when you use your Tern as a daily wear watch due to increased screen on time� Things You Can Do To Reduce Burn In •...

  • Page 67: 19� Tern Specifications

    Operating Instructions 19. Tern Specifications Tern Specifications (cont.) Specification Tern Battery 20 hours diving (medium brightness)� Operating Life 6 months in Standby Operating Modes Nitrox Communications Bluetooth Low Energy 3 Gas Nitrox Dive Log Over 400 hour detailed log at 10s logging...

  • Page 68: 20� Regulatory Information

    THIS DEVICE COMPLIES WITH PART 15 OF THE FCC RULES� Code 6, obtainable from Health Canada’s website� OPERATION IS SUBJECT TO THE FOLLOWING TWO Tern Dive Computer Contains TX IC: I2208A-05 CONDITIONS: (1) THIS DEVICE MAY NOT CAUSE HARMFUL INTERFERENCE, C) EU and UK Conformance Statements •...

  • Page 69: 21� Contact

    Operating Instructions 21. Contact www.shearwater.com/contact Headquarters 100-10200 Shellbridge Way, Richmond, BC V6X 2W7 Tel: +1�604�669�9958 info@shearwater�com Page 69 Doc. 15301-RevB (2023-11-24)

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