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FINDINGS LIBRARY · GAS AND SAFETY

No gas detector on a boat: LPG sniffers, solenoids and what surveyors check

UPDATED 5 NOVEMBER 2026 · 3 EXAMPLE FINDINGS · 1 SOURCES

Why a boat with an LPG cooker needs a gas detector and solenoid shut-off, where the sensor goes, what to do in a leak, what a surveyor checks and three example findings graded A, B and C.

AT A GLANCE
No gas detector
USUAL GRADE
A for a gas leak found or a smell of gas. B for an LPG system with no detector or no solenoid shut-off. C for a detector that needs testing or a sensor in the wrong place
FOUND WITH
Following the gas system from cylinder to cooker, looking for the sensor low in the boat and the solenoid at the locker, and pressing the detector's test button
JUDGED AGAINST
ABYC A-1 for LPG systems. Practical Sailor recommends a pressure gauge, solenoid, regulator and sniffer, with the sensor at a low point where gas collects
REPAIR COST
A detector, sensor and solenoid, and fitting by someone competent with gas systems. Priced per boat

LPG is heavier than air. A leak from a cooker hose or a loose fitting sinks into the bilge, where nobody smells it, and waits for a spark from a pump switch or a starter motor. A gas detector is the only thing on board that notices before then.

What a gas system should have

ABYC A-1 covers LPG systems on boats. Practical Sailor's recommendation for a safe installation built to it: a pressure gauge to leak-test the system, a solenoid valve at the cylinder, a regulator, and an LPG sniffer. The sniffer is installed at a low point where the gas would collect. When it senses gas, at about 10 percent of the minimum explosive level, it sounds an alarm and closes the solenoid, cutting the gas to the appliances.

The cylinder sits in a proper locker that drains overboard; see LPG locker drain.

How a surveyor checks it

Follow the gas from the cylinder to the cooker. At the locker, look for the solenoid and a pressure gauge. Along the run, check the hose type and condition and every connection. In the galley, find the detector panel and the sensor, and check the sensor is low, near the cabin sole or in the bilge below the cooker, not at worktop height. Press the test button and confirm the solenoid closes.

With a pressure gauge fitted, a leak test is simple: open the cylinder, close it, and watch whether the gauge drops. A smell of gas, or bubbles at a joint, is an A on the spot.

No gas detector: example findings

The same defect written up at each grade, the way Axsail writes it from what the surveyor says on board. The grade follows what was found, so use these as wording, then grade what you see.

GASA
Galley and bilge below

Smell of gas in the galley with the cooker off. Bubble test at the cooker hose connection shows a leak. No gas detector or solenoid fitted.

Recommendation: Close the cylinder valve and do not use the gas system until the leak is repaired and the system checked by a competent gas engineer.

GASB
Gas system

LPG cooker supplied from a cockpit gas locker. No gas detector, no solenoid shut-off and no pressure gauge. No leak found.

Recommendation: Fit a marine gas detector with its sensor low in the galley area, a solenoid at the cylinder and a pressure gauge for leak testing, within 12 months.

GASC
Gas detector sensor

Gas detector and solenoid fitted and working on test. Sensor mounted at worktop height behind the cooker.

Recommendation: Move the sensor to a low point near the cabin sole below the cooker, where leaked gas would collect, at the next maintenance period.

ASafety. Safety or compliance deficiency. Fix before the vessel is next underway.
B12 months. Deficiency that needs timely attention. Fix within about 12 months.
CRoutine. Note or observation, cosmetic or maintenance. Routine maintenance at the owner's convenience.

What the fix costs

Job Reported cost
Gas detector with sensor Detector price
Solenoid valve and pressure gauge at the cylinder Parts and fitting
Fitting and leak test Gas engineer's time
Moving a badly placed sensor Owner or electrician's time

Photos to take

The detector panel, the sensor where it's mounted, the solenoid and gauge at the locker, and any suspect joint. With Axsail, say what you see as you take each photo and it goes on the gas finding.

Writing it up

Say what gas appliances are fitted, whether there's a detector, sensor and solenoid, where the sensor is, whether they worked on test, and the result of any leak test. If you smell gas, the finding says so first: "gas smell in galley, cylinder closed, do not use the gas system".

Frequently asked

Where should a gas detector sensor go on a boat?

Low down. LPG is heavier than air and sinks, so Practical Sailor says the sniffer belongs at a low point where the gas is most likely to collect, usually near the cabin sole below the cooker or in the bilge under it.

What does the solenoid do?

It's an electrically operated valve at the cylinder. When the detector senses gas, Practical Sailor notes it sounds an alarm and closes the solenoid, cutting gas to the appliances. Practical Sailor says sniffers trigger at about 10 percent of the minimum explosive level.

What should I do if I smell gas on board?

Practical Sailor's plan is to close the cylinder valve by hand, switch nothing electrical on or off, kill power at the main battery switch, and open hatches and ports. At sea, get to a high point on deck. At a dock, warn the neighbours, the marina and the fire service.

Is a gas detector required on a boat?

Rules vary by country and use, and charter licences can require one. For an inspection, a surveyor reports an LPG system without a detector and solenoid as a deficiency because the leak it would catch can destroy the boat.

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Standards it's judged against

ABYC A-1

Liquefied Petroleum Gas (LPG) Systems

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