Prerequisites

NauticCalc on your iPhone (iOS 17.6+, app version 1.7.0 or later)
An NMEA gateway that puts the instrument data on the onboard Wi-Fi
The gateway's host or IP address and port (commonly 10110 for NMEA 0183, 3000 for Signal K)

Step 1: Join the right Wi-Fi

Connect the iPhone to the onboard Wi-Fi the gateway is on — not the marina network and not mobile data. Without a shared network there is no connection.

Step 2: Open the onboard instruments

Under Navigation you will find Onboard instruments (NMEA). The screen is marked beta and is being switched on gradually; if it does not appear yet, it has not been enabled for your device.

Step 3: Choose the data source

Pick the transport your gateway speaks:

NMEA 0183 — text sentences, the most common case with Wi-Fi gateways
Signal K — when a Signal K server is running on board
NMEA 2000 — for gateways that pass the bus through raw

The port switches to the usual default when you change transport, as long as you have not set it yourself.

Step 4: Enter host and port

Fill in Host / IP (for example 192.168.4.1) and check the port. Both are in the gateway's manual or its configuration interface.

Step 5: Connect and allow the network

Tap Connect. The first time, iOS asks for local network permission — without it the connection stays silent. If the dialog was dismissed by accident, you can grant it later under Privacy in the iOS settings.

Once the status reads Connected, the live values fill in: speed through water, speed and course over ground, apparent wind and depth. A dot next to each value shows how fresh it is.

Step 6: Carry values across

The live values can be carried into the calculators, the logbook and voyage planning at the tap of a button. For correction work make sure you take speed through water rather than speed over ground — with current running the two differ noticeably.

Common mistakes

The iPhone is on the wrong Wi-Fi or on mobile data
Local network permission declined; the iOS dialog only appears on the first attempt
Wrong port for the chosen transport
Speed over ground carried across instead of speed through water
Expecting values no instrument provides — no log transducer, no speed through water

Connect an NMEA gateway and carry values across