DIY Ozone Generator - Get Rid of Bad Boat Odors & Musty Cabin Smells

DIY Ozone Generator – Get Rid of Bad Boat Odors

DIY Ozone Generator: the Ionizator

​Does the cabin of your boat have this typical "musty" smell? This is most likely caused by ​moldy areas behind ceiling covers or in your cushions. In the long term, you should make sure to avoid the cause for this problem. But there is also a quick and easy short-term solution: build a DIY ozone generator.


​In this article, I will show you how to build your own DIY ozone generator. All you need is a box, a fan, a cheap but powerfull ​ioniser and some wiring supplies. The resulting generator will be just as good as a commercial one for a few hundred bucks.


  • Ozone can cause serious health hazards. Never stay in the same room when the ozone generater is running. Always wait a few hours after pulling the plug before entering the room.
  • ​​Mistakes in AC wiring can be deadly. Even though the wiring is pretty simple in this case​, I assume you know what you are doing. When in doubt ask an expert!

​The Problem: Musty Smell Below Decks

​As soon as I can remember, the old little cabin cruiser of my ​grandfather had this particular smell to it. A mixture of the moldy odor of an old basement and the scents from the kerosene lamp and the little alcohol stove.

As a kid, this smell always had a positive connotation, as it reminded me of the ​carefree days of cruising in my childhood. Yet, already back then I had noticed that everything I ​took home from the boat had absorbed that odor. All my clothes had that "boat smell" to them and my friends could already tell that I had been sailing as soon as they approached me.

​Not everyone shared that positive connotation of "boat smell = sailing vacation", and even I realized, that this odor might ​even be a serious health risk.

The cause for this typical boat smell can be found ​in cushions, behind ceiling covers and in other inaccessible areas. This is where mold starts to build up due to trapped moisture and  insufficient ventilation. The problem is very common and there is a straightforward solution: Get rid of all mold by completely remodeling your boats interior, making sure to eliminate the root of the problem.

While this is ​guaranteed to work and to have the most long-lasting effects, it is also extremely time-consuming and expensive. If you want to postpone the extensive remodel and go out on the water instead, there is a great and ​temporary solution that should get rid of the problem for the coming weeks or even months: kill off the mold and germs with ozone.

​The Solution: Ozone Treatment

​Ozone is ​a gas that consists of nothing but oxygen. However, each ozone molecule consists of ​a triple of oxygen atoms instead of the usual ​pair. This makes ozone highly corrosive and thus deadly to all forms of bacteria, fungi and viruses. Since ozone is highly unstable, it only lasts for a short ​while before literally vanishing into thin air again. An ozone treatment is thus a very environmentally friendly way to disinfect your boat, since no chemicals are involve apart from the oxygen that​ is already in the air.​​​​

​In the form of ozone, this oxygen is also highly toxic to humans, so ​​do not enter your cabin while the ozone generator is running and wait at least two hours after you pulled the plug! ​I will now show you how I build my own ozone generator.

A little note on the corrosiveness: Some people have raised concerns that the ozone might also attack metal and rubber parts on your boat. While this is indeed a theoretical risk, tests done by a German yachting magazine have shown no harm in any of the test items that were left on board during ​an extensive ozone treatment. However, make sure to check all vital parts of your boat after the treatment!

​How to Build a DIY Ozone Generator

All you need to follow these instructions are:




wiring supplies

​​The assembly is simple: install the ​ioniser in a box that is open on two sides and ​attach the fan on one of the sides. ​The fan is ​crucial to ensure that the ​ioniser gets enough cooling and that the ozone ​is properly distributed in the room. Then you have to wire the fan and the ​ioniser and install a switch or put it behind a timer switch.

​​DIY Ozone Generator in a Whiskey Box

​I used a whiskey box for my assembly, as the opening of the box fitted perfectly to the dimensions of the fan I used. The nice thing is that the money I saved by not buying a pre-assembled ozone generator actually paid for the content of the box... 😉

​Putting the Ozone Generator to the Test

​I put my ozone generator to the test in the ​little cabin cruiser of my granddad. I made sure to place the generator on a metal board, just in case that it would overheat. As the temperatures were quite low, I set up an electric heater before the assembly in order to reduce the relative humidity of the air. (Somewhere I read that this would lead to better results.) I then lead the power-cable outside of the cabin, closed the hatches and plugged it to the shore power.

Testing the generator on the boat

After a while, a smell of swimming pool was noticeable even on the dock, so I made sure to keep a safe distance. I let the generator run for about 20 minutes and then pulled the plug. After another 2 hours of waiting, I opened the hatches.

The results were staggering: No more bad odors, just a fresh smell ​of "cleanliness". ​ I was very pleasantly surprised that the good smell lasted for at least four weeks. After that time, some of the ​​​musty smells came back, but even after a few months, the ​boat still smelled much better than before.

​In conclusion, I will keep using ​my DIY ozone generator every few weeks until I will find to remodel the boat's interior.

​Other DIY Constructions

​Over time, readers of the German version of this article have come up with their own creative constructions. Here we present three ways how the ioniser can be integrated into various types of boxes.

Alternative assembly 1: Replace a heating element with the ​ioniser

​A user from a sailing forum has used an old electric heater and replaced the heating element with the ioniser. This way the fan in the device is optimally set up to cool the ioniser and distribute the ozone in the cabin. Thank you, Wuggi for providing the images of your construction!

Alternative Assembly 2: ​Ozone Generator in a Plastic Box

​Jörg posted his construction based on this article in a German Facebook group for DIY projects on boats. He used a plastic box and two computer-fans, one blowing fresh air into the box and the other one sucking the ozone out. Thank you, Jörg for showing us your assembly.

Alternative Assembly 3: Wooden Box with two Ozone Generators

Udo made a nice wooden box in which he placed two ozone units with a separate fan for each one. He was very happy with the odor removal of his assembly. Thanks ​to Udo for letting us use the pictures of his DIY ozone generator.

​Show us your work!

​Want to build your own? ​Write in the comments if you have any questions! And feel free to send us some pictures of your assembly!


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