A man overboard system for a sailboat used to mean a horseshoe, a dan buoy and whoever was on deck. In the last year four pieces of kit have turned up that make the bad night less likely, or shorter: Garmin's OnBoard wireless tags, the FLIR Ocean Scout Pro thermal monocular (both in Yachting World's new sailing gear for 2026), Digital Yacht's SafeLi gas alarm for lithium banks and its Bilge IQ pump monitor. For each one, what it does, what it does not replace, and whether it would go on a cat like ours. We have not tested any of it. Everything here is from the makers' pages and from people who have run the gear on their own boats, with links. Our last few safety posts were about things going wrong, a whale strike off Norfolk Island and a reef strike in the Whitsundays. This one is the other side of it.
Garmin OnBoard: a kill switch that knows who went in
Garmin announced OnBoard in October 2025. A hub wires into boat power, the NMEA 2000 network and the engine stop circuit. Everyone aboard wears a small tag on a wrist band, a carabiner or a key ring float, up to eight per boat, each set as captain or passenger. When a tag goes under the surface its radio link to the hub breaks, the alarm sounds, the chartplotter drops a man overboard waypoint, and if it was a captain tag the engine stops. Holding the button on a captain tag for two seconds does the same on purpose. Tags switch off for a swim and the battery lasts more than a season, Garmin says.
Ben Stein at Panbo has had one on his boat since May and his OnBoard review is the one to read. The alarm went off at about 350 feet in his test on land, and breaking into the engine wiring was the worst part of the install. NZD 999 for the system and NZD 289 a tag in New Zealand, AUD 899 and AUD 259 in Australia, USD 499 and USD 149 in the States. The catch for most cruising boats is in the name of his review. It needs a Garmin ECHOMAP or GPSMAP plotter. Mā Tori runs Raymarine, so for us it is a plotter swap first.
What a kill switch does on a boat under sail
Nothing to the sails. OnBoard comes out of the outboard world, where United States law has required the driver of a boat under 26 feet to wear a cut-off link at speed since 2021. On a cat doing 8 knots under main and headsail with the autopilot steering, the engines are off anyway. Cut them and she carries on at 8 knots, about 250 metres a minute away from the person in the water. Practical Sailor's look at wireless cut-off systems makes the same point, and its readers have wired relays so the alarm also drops the autopilot, which at least lets the boat round up. Garmin has not published a way to do it.
So on a sailing boat the system buys you an alarm the second the tag goes under, with nobody needing to see it happen, and a waypoint on the plotter without anyone pressing a button. On a two-person boat at 0300 that is the difference between a search that starts now and one that starts when the off-watch wakes up to an empty cockpit. Stopping the boat and getting back is still on the person left aboard.
The AIS beacon is still the base layer
A tag says someone has gone, not where they are ten minutes later in a seaway. That is the AIS beacon's job. The Ocean Signal MOB1 is the one most cruisers know: 92 grams, fitted inside the jacket, fires when it inflates, first alert inside 15 seconds, then the person's position on AIS to every receiver within about 5 miles plus a DSC alarm on your own VHF, for 24 hours. Ocean Signal's page says the MOB1 does not meet the newer Class M standard and has been superseded in the UK and EU, so ask what your flag state accepts before buying.
The Maritime NZ guidance for a yacht leaving New Zealand asks for a PLB or AIS beacon per person on a short-handed boat. The rest of that list is in our NZ Cat 1 inspection checklist. The tag raises the alarm, the beacon gets you back to the person. Neither does the other's job.
FLIR Ocean Scout Pro: finding a head in the water at night
On a black night in a metre of swell, a few metres is still a search. The FLIR Ocean Scout Pro is a handheld thermal monocular that sees heat instead of light, and FLIR's figure for picking up a person in the water is 500 metres. The sensor is 640 by 480, the field of view 32 degrees with 2x to 8x zoom, battery up to 6 hours, 498 grams, IP67 and rated for a 2 metre drop. FLIR lists it at USD 2,599.99 and GBP 2,338.80. We have not found an NZD price.
What it does not do is look for you. Someone still has to be sweeping the right arc, and 500 metres is the maker's number, not a promise in rain and spray. Where it earns its keep every night is on watch: an unlit fishing boat, a FAD, a reef edge a different temperature to the water around it. Nothing on the plotter replaces eyes at night, and this gives the eyes a better chance.
SafeLi: a smoke alarm for a lithium bank
Mā Tori carries 540 Ah of lithium, so this one got our attention. Digital Yacht's SafeLi announcement on 15 October puts the case plainly: LiFePO4 is far more stable than older lithium chemistries, but an overcharged or voltage-spiked cell can vent, the main gas is hydrogen, hydrogen is flammable at very low concentrations, and a battery compartment usually has a bilge pump, a contactor or a fan in it that can spark. SafeLi is a sensor box next to the bank, powered off the NMEA 2000 network, with a gas sensor for hydrogen and other volatiles and a temperature sensor. It pops a warning on compatible helm displays, shows live readings on a phone, has its own alarm, can drive Digital Yacht's NMEA 2000 Klaxon, and pushes a notification through Njord Cloud when you are ashore. It was previewed at Annapolis this week (see our Annapolis show post) and launches at Metstrade in November. No price yet, and no published alarm thresholds.
What it does not do: cut the charge, stop a vent, or make up for a BMS that is not doing its job and a charger on the wrong profile. It is a smoke alarm. Nobody fits one instead of wiring the house properly, and nobody sensible leaves one out.
Bilge IQ: knowing the pump ran at three in the morning
Bilge IQ won best new product at the NMEA 2025 conference, and Panbo's report from NMEA 2025 explains the thinking. It sits between the pump, the float switch and the power feed, counts every activation, logs run time, amps and volts, and puts seven alerts on the NMEA 2000 network: pump running, running dry, not running with the float up, float switch failure, water at a second high-water float, high current and low voltage. It takes any 12 or 24 volt pump to 10 amps, talks to a Victron GX, and Digital Yacht's Bilge IQ introduction lists it at USD 329.95 ex VAT, shipping from December 2025. Panbo had expected about USD 249. One unit per pump, so on a cat that is two.
Water coming in that nobody knows about is how a boat gets to the point where the pumps are the story, and a pump that has run eleven times since midnight is something you want to hear about at the first cycle. Digital Yacht says the manual switch always overrides the unit. What the pump does if the unit itself fails is not spelt out in anything we have read, and we would ask before fitting it.
What we would fit on a Fusion 40, in order
- An AIS beacon in every lifejacket, if the boat does not already have them. The departure assessor asks for them anyway.
- SafeLi, once it ships with published thresholds. A lithium fire is the one we cannot step away from.
- Bilge IQ, one per hull, wired so the alert wakes the off-watch.
- The thermal monocular, when the budget stretches.
- OnBoard, only on a boat with a Garmin plotter. On a cat under sail it is an alarm and a waypoint, not a stop button, and you fit it knowing that.
None of that replaces the free stuff: tethers clipped on before you leave the cockpit at night, an MOB key on the plotter everyone can find without looking, and a drill the crew has actually run. The Golden Globe lessons post made the point about two systems that share nothing, and it applies here as much as to rigging and radios. Our set-up is in the Fusion 40 review.
What we don't know
- SafeLi's price, its alarm thresholds and its ship date beyond "Metstrade".
- Whether OnBoard can be made to drop an autopilot. Readers have done it with relays, Garmin has not published a way.
- How far the Ocean Scout Pro really sees a head in rain. 500 metres is the maker's figure.
Safety requirements and prices change. Check the current Maritime NZ guidance, your own flag state's rules and the maker's page before you rely on anything here.
Questions people ask about man overboard systems
Does a man overboard system work on a sailboat under sail?
The alarm and the waypoint work the same under sail as under power. The engine cut-off does nothing to a boat driven by her sails and autopilot, so what you get is an instant alarm and a position, not a boat that stops.
What is the difference between a wireless MOB tag and an AIS MOB beacon?
A tag such as Garmin OnBoard tells the boat someone has gone in and marks the spot. An AIS beacon on the lifejacket, such as the Ocean Signal MOB1, sends the person's live position to every AIS receiver within a few miles for 24 hours. The tag raises the alarm, the beacon gets you back to the person.
Does Garmin OnBoard work with Raymarine or B&G chartplotters?
No. Garmin says OnBoard is set up and run from compatible Garmin ECHOMAP and GPSMAP chartplotters. A boat with Raymarine, B&G, Simrad or Furuno at the helm would need a Garmin display added.
Do you need a gas alarm on a LiFePO4 battery bank?
Nothing in the NZ departure requirements asks for one as far as we can find. Digital Yacht's case is that an overcharged or spiked LiFePO4 cell can vent hydrogen, which is flammable at low concentrations, near things that spark. An alarm does not stop a vent or replace a BMS and a correct charge profile. It tells you early. Check your flag state's rules and your insurer.
Keep reading: the smaller upgrades we would fit are in new gear from the Southampton show, the printable safety and survey checklists are in the Catamaran Buyer's Pack, and our bluewater catamaran for sale is the boat this was written from.