Range ring — how far the fuel aboard takes you
Read the fuel range ring on the chart: what the two circles mean, where the number comes from, and why the ring may not be there.
The chart draws two circles around your boat. The solid teal ring is your range at reserve — how far the fuel aboard takes you while still holding one fifth of it back. The faint dashed ring outside it is the full range with nothing held back. Both shrink as you run.
The chip beside the ring says how far and where the number came from. "Counted by the bus" means the NMEA bus is reporting your fuel flow (and tank level, and speed) live. "From your last fuel log" means the bus is not reporting a burn rate, so the ring uses the gallons-per-hour from your most recent fuel entry that has engine hours. "At your cruising speed" means the bus has no live speed over ground, so the ring uses the boat's cruising speed (Vessel cruising speed, set in a trip's leg editor). When the tank and the burn rate come from different places the chip names both.
The ring is never a guess. It is missing when there is no burn rate to use (no live fuel flow and no fuel entry with engine hours), no speed to use (no live speed and no cruising speed set), no fuel reading, or no position to centre it on. Fix the missing piece and the ring appears.
A bus reading counts as live for five minutes after the bridge last reported it; after that the ring falls back to your fuel log and says so.
Steps
-
Open the chart
Tap the Chart tab or the map card on Mission Control. The ring is drawn around your boat whenever it has a burn rate, a speed, a fuel reading, and a position.
-
Read the two rings
Plan against the solid teal ring — that is your range with a one-fifth reserve kept back. The faint dashed ring is the full range with no reserve.
-
Read the chip
"Range 62 nm at reserve · counted by the bus" — the second line tells you the source: the bus, your last fuel log, or your cruising speed. Tap the chip to open the Fuel Log.
-
Keep the number honest without a bus
Log every fill with the engine hours at the fill — that is what gives the ring a gallons-per-hour figure. Set the boat's cruising speed so the ring has a speed when you are stopped or the bus is quiet: open a trip's Edit Trip (or New Trip) sheet, tap a leg, and set Vessel cruising speed — it is the boat's, not the leg's, and every leg uses it. Vessel Setup has no cruising-speed field.
-
Hide or show the ring
On the chart, open the hamburger (☰) drawer → Navigation Tools → Hide Range Ring / Show Range Ring. The choice sticks across launches.
Related
- Log a fuel stopRecord a fill-up so consumption math works.
- Log a fuel fill — gallons, marina, receiptRecord a fuel fill so theONE can compute gallons-per-hour against engine hours.
- Chart — what the chart and map show youRead the chart view — your vessel's position, course over ground, breadcrumb track, and the chart layers underneath.
- Chart layers — GPS, channel markers, weather radar, buoys, track lineToggle the five chart overlays — GPS position, channel markers (AtoN buoys and beacons from NOAA), NEXRAD weather radar, NOAA weather buoys and the track line — and start a cruising track from the Track line row.
- Enter telemetry by hand — one-off readingsHow to log fuel level, tank levels, battery state, wind, engine temps manually.