If you trailer your boat, the trip starts on the highway and not at the dock. Helm is a marine navigation app for iPhone and iPad, and it has a CarPlay interface, so the nautical chart of the water you are driving toward comes up on the vehicle's built-in screen instead of a phone wedged in a cupholder.
CarPlay is Apple's system for putting an iPhone app on the screen already built into your car or truck. You connect the phone with a cable or wirelessly, the vehicle's display becomes the app's display, and the phone stays in your pocket or on the charger. CarPlay comes built into new vehicles from the major US brands, and aftermarket head units add it to an older truck. Helm ships with a CarPlay interface built in, so once Helm is on your iPhone it appears on the CarPlay screen alongside the other apps your vehicle already shows.
Helm's CarPlay interface is a chart view. It puts the same nautical chart you navigate with on the larger built-in display, with your position on it, so the map on the dash is the water rather than the road. That is the whole idea of it: a bigger, glanceable look at where you are headed while somebody else is doing the towing, or while you are parked at the ramp with the engine still running.
A few situations where boaters reach for it. You are an hour out from a reservoir you have never launched on, and you want to see the shape of the lake and where the ramp sits relative to the creek arm you plan to fish. You are pulling into a state park ramp at 5am in the dark and want the chart up on a screen you can read without unlocking a phone. You are in the passenger seat on the way to the Keys with tomorrow's run up on the screen while the driver stays on the road.
The trip back is when people plan the next one. The chart is on the screen, and the trip you just recorded is in the logbook on the phone, ready to open at home.
CarPlay is the drive. The reason to run Helm is what happens after the boat is off the trailer.
Enter your boat's draft once. Helm shades the water you cannot cross and routes around it instead of drawing a straight line over a bar. A skinny-water route for a flats boat and a route for a cruiser with a deep keel are different routes, and Helm knows which one you are asking for.
Helm merges four independent sources and reports what is under the keel. It also surfaces CATZOC, the chart's own confidence rating for the area you are looking at.
| Source | What it contributes |
|---|---|
| NOAA ENC | The official electronic navigational chart for US waters. |
| USACE eHydro | Army Corps dredging surveys, the freshest reading in maintained channels. |
| State lake elevation data | Inland lake depth, which is why a reservoir is a charted surface. |
| NOAA CO-OPS tide | The live water level, so a chart datum number becomes today's depth. |
Tide predictions come from NOAA CO-OPS against the MLLW datum, and tidal current arrows rotate as you scrub the time forward. The chart carries animated wind, wave and current overlays, and a multi-day strip with three-hour columns for wind, gusts, air temperature, rain and water temperature. Scrub to Saturday at noon and the arrows show you the push you will get on the run out.
Helm is offline first. There are 161 downloadable chart packs. With the pack for your water on the device, charts, routing, depth, the measure tool and the anchor alarm all work without cell service, which is the normal condition three miles into a marsh or on the back side of an island.
Depth, speed over ground and course over ground sit on one strip. Live vessel traffic is on the chart: position, vessel type and movement status, so an anchored tanker reads differently from one under way, and the visible area refreshes about every ten seconds while the layer is on. An anchor alarm wakes you if you drag overnight. Satellite and night chart styles cover a bright afternoon and a run back after dark. Every trip is recorded to a logbook you can replay, which is how you find the same spot again next month.
Draw a line anywhere on the chart and Helm returns distance, bearing and a depth profile along it, including where the shallowest point falls. Use it before you cut a corner across a bar or take an unfamiliar channel on a falling tide.
Helm is native on both, and routes, markers, tracks and the logbook sync across your devices. Lay out Saturday's run on the iPad at the kitchen table on Friday night, and it is on the iPhone that drives the CarPlay screen the next morning, along with every spot you have saved.
Yes. Helm is a marine navigation app for iPhone and iPad with a CarPlay interface built in, so the nautical chart appears on your vehicle's built-in screen on the way to the ramp.
The chart view: the nautical chart with your position on it, on the vehicle's display instead of the phone's.
Install Helm on your iPhone and connect the phone to a CarPlay vehicle the way you normally would, by cable or wirelessly. Helm appears with your other CarPlay apps.
Yes. Download the chart pack for your area first. Charts, depth, routing, the measure tool and the anchor alarm all run offline on the phone or iPad.
Yes. You enter your draft once, and from then on Helm shades water you cannot cross and plans routes around it.
Yes. Coastal water, the intracoastal, rivers and inland lakes. Lake depth comes from state elevation surveys rather than NOAA charts.
Helm Boating