This article was kindly provided by Towergate Insurance, who provide competitive insurance quotes for fishing and cruising boats.

The Dangers of Carbon Monoxide on Boats

There are many obvious risks to travelling by boat. From gastric flu to the ship itself sinking, these risks can run from the inconvenient to the truly terrifying. But there is another risk which can be encountered in boat travel that doesn’t get spoken about as much. It’s a silent killer – almost undetectable – and the consequences can be fatal. It is, of course, carbon monoxide poisoning.

How Do Boats Produce Carbon Monoxide?

Carbon monoxide is a by-product of most older engines and petrol-powered generators, as well as other appliances which run on gas, LPG, coal, wood, paraffin or oil. It’s colourless, odourless and non-irritating, which makes it almost impossible to detect without some kind of sensor.

On boats, carbon monoxide can be produced in one of two ways – by the boat’s engine, or by a generator. Generators tend to be commonly used by people on boating holidays, who may be moored up somewhere and have a need for an electrical power supply.

How Does Carbon Monoxide (CO) Become Dangerous?

The circumstances in which CO gas can become dangerous are relatively simple. For the gas to make a person ill, it would need to be produced in a poorly ventilated and/or enclosed space. If any of the above types of appliances are used in such a space they will, at some point, produce enough CO for it to become harmful.

Many appliances which produce carbon monoxide can be safely used indoors, as long as they vent the gas in a safe manner. However sometimes an appliance will develop a fault which prevents it from doing so. In this case, CO could build up inside a space without anyone realising. And because boats are designed to be water proof, an on-board CO leak can quickly turn deadly.

The Importance of a CO Warning System

To make sure you’re as protected as possible against any unforeseen CO leaks, it’s also important to install the proper warning systems. Carbon monoxide detectors can take many forms, including coloured chemical pads and alarms. A sticker, for example, will change colour in the presence of CO. The alarm will make an unmistakeable noise. Whilst both have their individual merits, it’s advisable that you use a combination of warning systems which can protect you both whilst your awake, and asleep.

How to Prevent CO Poisoning on Boats

Having faulty equipment on boats is dangerous at the best of times. But this goes double for appliances which produce carbon monoxide. So the most important thing to remember when travelling by boat is to make sure that all onboard appliances and equipment are working properly and venting gas by-products in a safe manner.

There have been cases of carbon monoxide gas escaping from equipment which has developed a fault, then been poorly repaired by the owner. Unless you are qualified and experienced in fixing a particular piece of equipment, it’s best to leave it to the professionals. The cost of having equipment fixed or replaced can be high, but this cost can be managed by choosing comprehensive boat insurance from And at the end of the day, there’s nothing more valuable than a life.