# EssentialSail NMEA — User Manual **Version 1.57 (build 57)** · Updated 22 September 2026 Support: support@essentialsail.com · Online guide and support: https://essentialsail.lovable.app/guide#support > **Safety notice.** EssentialSail NMEA is a supplementary aid. It does not replace certified navigation equipment, a proper lookout, or good seamanship. GPS accuracy, wireless links and phone hardware can all fail. The Anchor Watch in particular must never be your only safeguard: check your anchor visually and set a conservative radius. --- ## 1. What the app does EssentialSail NMEA turns a phone, tablet or head unit into a boat instrument display. It connects over Wi-Fi to your boat's NMEA gateway or multiplexer and shows: | Screen | What you get | |---|---| | **Wind** | Apparent or true wind on a compass-rose gauge, with speed | | **Depth** | Depth, or clearance under the keel if a draft is set, with colour warnings | | **Speed** | Speed over ground (SOG) or through water (STW), plus heading/course | | **Heading** | A heading-up rotating steering compass, like a boat's own binnacle compass | | **Dashboard** | 2 to 6 instruments on one page (depth, wind, speed, heading, AIS radar, anchor, camera) | | **AIS radar** | Nearby vessels, collision warnings (CPA/TCPA and CBDR), alarms | | **Anchor Watch** | Drop the anchor, set a swing radius, get an alarm if you drag | | **Camera** | Live RTSP/ONVIF video from a camera on board | | **NMEA** | The raw sentences arriving from your instruments (for troubleshooting) | The app is available in **English, French, Italian, Spanish, German, Portuguese and Dutch**. --- ## 2. Before you start You need: 1. An **NMEA gateway or multiplexer with Wi-Fi** (NMEA 0183 over TCP or UDP, or NMEA 2000 through a converter). 2. Your device connected to that gateway's Wi-Fi network. 3. The gateway's **IP address and port**. The app's defaults are `10.10.100.254` and port `10111` (TCP), which suit many marine Wi-Fi gateways. Check your gateway's manual if yours differs. Optional: a boat GPS on the NMEA network (or use the device's own GPS), an AIS receiver, and an RTSP camera. ### First launch 1. Accept the **location permission** request. It is used only for the device GPS (Anchor Watch, AIS range, GPS speed when no boat GPS is available). 2. On the first start, the app shows the subscription screen (see section 9). Once you are past it, a short **tips carousel** (7 tips) explains swiping, themes, page settings, display options and the dashboard, and ends with **"Ask Questions & Features"**, which shows the address of the online guide and support page (https://essentialsail.lovable.app/guide#support). Tick "don't show again" if you want. 3. Go to **Settings → Connections**, enter the gateway IP and port, and tap **Connect**. --- ## 3. Getting around ### Swiping between pages **Swipe left or right** anywhere on the screen to move between pages. The page order is: **Wind → Depth → Speed → Heading → Dashboard → AIS → Anchor → Camera → NMEA → Settings → Design** Only the pages you have switched on are in the loop (see *Design*, section 8). Settings and Design are always at the end. > **Out of the box only Dashboard, Depth, Wind and Speed are visible.** To use AIS, Anchor, Camera or NMEA, switch them on in **Design → Visible Screens**. The app opens on the **Wind** page by default. You can change this in Settings → App → Start Screen. ### Changing the theme (day / evening / night) **Double-tap an empty area** of any screen to cycle through the three themes: 1. **Light** (day) — grey/white, blue accents. The default. 2. **Marine** (evening) — deep navy with cyan accents. 3. **Dark** (night) — black with red accents, to protect night vision. ### Connection warnings If you are connected but no instrument data arrives, a red banner appears at the top: **"Instruments disconnected — check connection."** Instrument values also clear to `---` when they go stale: depth, wind and speed after **10 seconds** without an update, GPS position after **15 seconds**. --- ## 4. Connecting to your instruments (Settings → Connections) ### Primary server 1. Enter the **IP address** and **Port**. An invalid entry turns red. 2. Choose **TCP** or **UDP**. 3. Tap **Connect**. The status indicator shows *connecting*, then *connected*. Errors appear in red under the indicator. Changes to IP, port and protocol are saved automatically when you leave the field. ### Secondary server (optional) Switch on **Secondary Server** to receive from a second source at the same time, for example the main gateway for instruments and a separate AIS receiver. It has its own IP, port, protocol, status indicator and Connect/Disconnect buttons, laid out the same way as the primary server's. Data from both servers is merged into one stream automatically. Default port for server 2 is `10110`. ### Auto Connect Switch on **Auto Connect** to connect to your server(s) each time the app starts. --- ## 5. The instrument pages ### 5.1 Wind A compass-rose gauge shows the wind angle and speed. Port side is red and starboard side is green. Tap the round **A / T** button to switch between **Apparent (A)** and **True (T)** wind. How true wind is obtained is set in Settings → Data Sources → **True Wind Calculation**: - **Instrument (MWV/VWT)** — taken directly from your wind instrument. Most accurate. - **Calculated (AWA + GPS SOG)** — computed from apparent wind and GPS speed. - **Calculated (AWA + Log STW)** — computed from apparent wind and the boat log. ### 5.2 Depth Shows the depth in large numbers. If you have set a **draft** (Settings → Boat), the page shows **CLEARANCE** (depth minus draft) as the main figure and displays both depth and draft at the bottom. Colour warnings are based on clearance under the keel: | Colour | Clearance | |---|---| | Blue/red theme colour | 1.5 m or more — safe | | **Amber** | Less than 1.5 m — caution | | **Red** | Less than 0.5 m — danger | Warnings only apply when a draft greater than 0 is set. Units (metres, feet, fathoms) are set in Settings → Units. ### 5.3 Speed Large speed reading in knots or km/h. The label under the number shows the source: **GPS** (device GPS), **SOG** (NMEA GPS, speed over ground) or **STW** (boat log, speed through water). Choose the source in Settings → Data Sources → **Speed Source**. SOG includes the effect of current; STW measures the speed of the hull through the water. ### 5.4 Heading A heading-up rotating steering compass, like a boat's own binnacle compass: the whole compass card (tick marks, N/E/S/W letters, degree numbers) turns so your **current heading always sits at the fixed marker at the top** — for example, if you are steering 180°, "S" appears at the top, not "N". This is different from the Wind page's compass rose, which stays North-up. A colored rim on the outer edge shows which side the wind is on (green = starboard, red = port), and the large number in the middle shows the heading in degrees plus the nearest compass letter (e.g. "181° S"). If the Maneuver widget's plotted heading is active (see 5.5), an amber marker also appears on this compass at the target bearing, sliding toward the top marker as you turn onto it and disappearing once you arrive. ### 5.5 Dashboard Several instruments on one page. The page holds **2 to 6 widgets** from: Depth, Wind, Wind Speed, Speed, Heading, AIS Radar, Anchor Watch, Camera and Maneuver. - Tap the **gear icon** (top right of the Dashboard) to choose which widgets to show. Tick or untick; the layout adapts (2 side by side, 3 as one large plus two small, 4–6 as a grid). - **Double-tap or long-press a widget** to promote it to the first (largest) position. - Inside widgets: the **A/T** button toggles wind mode, the **Z** button on the AIS mini-radar cycles its range (6 → 3 → 1.5 → 0.7 → 0.3 nm), and the Anchor widget has Drop/Weigh buttons. #### Maneuver widget (experimental) A tack/gybe helper. Pick a target wind angle (**30°, 60°, 90° or 120°** off the wind, on the opposite side to your current tack), then tap the **left or right turn arrow** — each arrow shows its own icon (bow-crosses-the-wind for a tack, stern-crosses-the-wind for a gybe) and how many degrees that turn takes, so you can compare both ways before committing. Turning left or right always ends on the same heading; only the maneuver and the turn distance differ, so there is no "wrong" choice here. Once you tap a direction, the widget shows **NEW HEADING** with the target number, and an amber marker appears on the Heading compass. The widget resets itself automatically once you arrive on the new heading (or tap the **X** to cancel early). This widget is still experimental: its text is currently only in English regardless of your chosen app language, and it may change or be removed in a future update. --- ## 6. AIS radar and collision avoidance Requires an AIS receiver feeding the NMEA network, and a valid GPS position. ### Reading the radar The radar is centred on your boat. Other vessels appear as targets. A counter shows the number of **Targets** in range, and the number of **Collision** (Warnings) targets. - **Green** — normal target - **Red, solid** — collision risk from CPA/TCPA - **Orange, dashed ring, "CBDR" label** — constant bearing, decreasing range Use the **zoom – / +** buttons to change the range: **6, 3, 1.5 or 0.75 nm**. Small Class B boats show their **name** once received (names are remembered between sessions); until then they show their MMSI number. Messages on the radar: **"No AIS data received"** means no AIS targets have arrived; **"No GPS"** means your own position is missing, and the radar cannot compute ranges or collision risk without it. ### Collision settings (shield icon in portrait, gear icon in landscape) **AIS Alarm** - **Enable AIS Alarm** — sound an alarm for nearby vessels. - **Collision Alarm Only** — on: alarm only for collision risk (CPA/TCPA guard). Off: alarm whenever a vessel comes within a distance you set (unit **km** or **nm**; default 0.5). **CPA / TCPA Guard Zone** — CPA is the Closest Point of Approach, TCPA the time until it. An alarm triggers when a vessel will pass closer than the **CPA guard** within the **TCPA guard** time. Presets: | Preset | CPA | TCPA | |---|---|---| | Coastal (default) | 0.3 nm | 15 min | | Offshore | 1 nm | 20 min | | Open Sea | 2 nm | 30 min | **CBDR Detection** — based on the COLREG rule of thumb: if a vessel's bearing stays constant while the distance shrinks, you are on a collision course. Adjust **Tolerance** (default 2°), **Min Samples** (default 3) and **Window** (default 120 s). It needs several position reports over time before it can flag a target. If both CPA/TCPA and CBDR are off, the dialog shows "All collision detection is disabled". Tap **Save** to apply changes. ### Silencing an alarm While an alarm is active, two buttons appear: **Mute** (speaker icon) and **Snooze** (clock icon, silences for **5 minutes**). Tap Mute again to un-mute. ### Your own vessel **Own MMSI** (Settings → AIS) removes your boat from the target list. If your AIS transponder sends its own data (VDO sentences), your MMSI and boat name are detected automatically and shown in green in Settings → Boat. --- ## 7. Anchor Watch A single-screen radar that watches for anchor drag using GPS. 1. Make sure a **GPS fix** is available. Until then the button is disabled and shows "Waiting for GPS…". 2. Set the **swing radius** with the **–** and **+** buttons (5 m steps, **5 to 200 m**, default 30 m). Choose a radius that covers your rode length plus the boat's length, and allow for a wind shift. 3. Tap **Drop Anchor** when the anchor is down and holding. The current position becomes the anchor point. 4. The radar shows a dashed circle for the radius, compass points, a blue trail of where the boat has drifted, the **distance** to the anchor and the **bearing**. The banner shows **"Anchor Holding"** and the elapsed minutes. 5. If the boat leaves the circle, a red **ANCHOR DRAG ALARM** banner appears and the alarm sounds. 6. The **speaker icon** in the banner turns the alarm sound on or off. 7. Tap **Weigh Anchor** to stop. In landscape, the radar is on the left and the controls in a column on the right. Anchor Watch depends on the device GPS or boat GPS and on the device staying on: enable **Keep Screen On** (Settings → App) and keep the device powered. --- ## 8. Camera, NMEA monitor, Settings and Design ### Camera Shows live video from any RTSP camera (including ONVIF cameras and VLC streams). Tap the gear icon and enter: - **Camera Name**, **IP Address**, **Port** (default 554) - **Username / Password** — leave both empty if the camera needs no login. Tap the eye icon to show the password. - **RTSP Path** — for example `/Streaming/Channels/101`. The dialog lists common paths (Type A–E, Marine POE `/stream1`, ONVIF `/onvif1`, Generic `/live`). - **RTSP Transport** — **Auto** (recommended, tries TCP first), **Force TCP** (more reliable) or **Force UDP** (faster, may drop frames). A preview of the URL is shown with the password hidden. Tap **Save & Connect**. Closing the dialog also saves. If the picture fails, the page shows "Connection Failed" with **Retry** and **Settings** buttons. The stream reconnects automatically when it ends. ### NMEA monitor Shows the raw sentences as they arrive. Use it to check that data is flowing and to identify which sentences your instruments send. **Pause** freezes the list; **Clear** empties it. ### Design - **Full Screen Mode** — hides the Android system bars for a dedicated helm display. (Swipe from the screen edge to bring them back temporarily.) - **Visible Screens** — tick the pages you want. At least one must stay selected. A line at the bottom shows the resulting page order. ### Settings Settings is one scrolling page of cards: | Card | Contents | |---|---| | **Connections** | Primary and secondary server, Auto Connect (section 4) | | **Data Sources** | GPS Position, True Wind, Speed Source | | **Units** | Depth (m / ft / fathoms), Wind speed (kn / m/s / km/h), Speed (kn / km/h) | | **Boat** | Detected vessel name/MMSI, **Draft Calibration** | | **AIS** | Own MMSI | | **App** | Keep Screen On, Refresh Rate, Start Screen, Language, Export Configuration, Close Application | | **Subscription** | Plan status, Manage/Subscribe | | **Support** | Device info, Save Debug Report, EULA, Privacy Policy | **GPS Position** — *NMEA Network* (boat GPS, default), *Device GPS* (the phone/tablet's own GPS, for use without instruments), or *NMEA + Device Fallback* (NMEA first, device GPS as backup). A panel shows whether GPS is active and the current coordinates. **Draft Calibration** — the distance from the waterline to the lowest point of the boat (keel and bulb). Many depth sounders already include a keel offset; if yours does, set this to 0. Otherwise enter your draft, and add about 5% if the boat is heavily loaded. Default is 1.0 m. **Refresh Rate** — Fast (200 ms), Medium (500 ms, default) or Slow (1 s). Slower rates give smoother numbers and use less battery. **Keep Screen On** — on by default. Recommended for cockpit use and essential for Anchor Watch. **Language** — System Default or one of the seven languages. **Close Application** — fully closes the app. (The Android Back button is disabled inside the app.) Tap the **?** icons next to settings for a short explanation. --- ## 9. Trial, subscription and lifetime licence The Google Play version includes all features in every plan. | Plan | Notes | |---|---| | **Monthly** | Recurring subscription | | **Annual** | Recurring subscription, best value among subscriptions | | **Lifetime** | One-time purchase, no renewals | - New users can start a **15-day free trial** with a monthly or annual plan. Cancel before it ends and you are not charged. Prices are shown in the app in your local currency. - On the first screen you can close the app with the **X** button or **"No thanks, close app."** - **Restore Purchases** re-checks your Google account. Use it after reinstalling or moving to a new phone. A lifetime licence bought on your account is recognised automatically on new devices. - **Manage Subscription** (Settings → Subscription) lets you switch plans or upgrade to Lifetime. Because monthly and annual are separate subscriptions, the app guides you to Google Play afterwards to **cancel the old plan** so you are not charged twice. - If you cancel, the app shows a "Cancelled" badge and the date access ends. Subscriptions renew automatically unless cancelled at least 24 hours before the period ends; manage them in Google Play → Subscriptions. - If a payment is pending, access is granted once it completes. **OEM / head-unit version.** The OEM build has no billing: it is always fully unlocked, shows no subscription screen and no trial dialog. --- ## 10. Troubleshooting | Symptom | What to check | |---|---| | **Won't connect** | Is the device on the gateway's Wi-Fi? Are IP and port correct (Settings shows your device IP for comparison)? Try TCP vs UDP as your gateway expects. Some phones switch to mobile data when the Wi-Fi has no internet — turn off "smart network switch" or mobile data. | | **Connected, but all `---`** | Open the **NMEA** page. If sentences scroll, the data is arriving: check that the instrument actually sends depth/wind/speed sentences and that the right Speed/True Wind source is selected. If nothing scrolls, the gateway is not sending to this port. | | **"Instruments disconnected" banner** | The link is up but no data for 10+ seconds. Check the gateway and the instrument bus. | | **No AIS targets** | AIS receiver connected to the multiplexer? Own GPS valid? Range zoomed in too far? | | **AIS shows my own boat** | Enter your MMSI in Settings → AIS, or let it auto-detect from your transponder. | | **Anchor Watch says "Waiting for GPS"** | Set GPS Position to *Device GPS* or *NMEA + Fallback*, grant the location permission, and go outside/near a window. | | **Wrong depth** | Check the Draft Calibration value against your sounder's keel offset. | | **Camera black or "Connection Failed"** | Check IP, port, username/password and RTSP path; try Force TCP; make sure the camera is on the same network. | | **Paywall keeps appearing though you paid** | Tap **Restore Purchases** and check you are signed in to the right Google account. | | **Screen turns off** | Switch on Keep Screen On. | ### Contacting support 1. Settings → Support → **Save Debug Report** and share the file. 2. Take a screenshot of the problem. 3. Send both to **support@essentialsail.com**. Use **Save / Export Configuration** (Settings → App) to save your settings (connection, units, vessel, AIS, dashboard, camera) as a JSON file for your records. Note: the app exports the file for you to keep or share; there is no in-app import. --- ## 11. Technical reference **NMEA 0183 sentences understood** | Data | Sentences | |---|---| | Depth | DBT, DPT | | Wind | MWV (preferred), VWR, VWT, MWD (legacy sources are used only if MWV is absent) | | Speed | RMC, VTG, VHW | | Position | GGA, RMC | | Heading | HDT, HDG | | AIS | VDM (other vessels), VDO (own vessel); Class A (types 1–3, 5) and Class B (18, 19, 24) | **NMEA 2000** is supported through a gateway that outputs NMEA 0183. **Permissions used:** Internet and network state (reaching the gateway and Google Play), Wi-Fi state, location (device GPS), wake lock (keep screen on). The app collects no personal data and shows no ads; settings are stored on the device. Read the in-app **EULA** and **Privacy Policy** in Settings → Support. The privacy policy is also available online: https://essentialsail.lovable.app/privacy **Requirements:** Android 8.0 (API 26) or newer. Works on phones, tablets and Android Automotive head units.