Nearly lost my boat yesterday

[Barnacle Bill]

I was moving the yacht back down the river from the boatyard in New Ross to its permanent berth (Waterford). Everything went OK, and we tied up, plugged in the shore line, turned on the dehumidifier, tidied up and had a cup of tea.

While we were waiting for our lift to arrive (to get back to my car), I was out on the pontoon and my son called from the boat "Dad - the dehumidifier just went bang. I unplugged it." I went back on board to have a look, and sure enough there was a nasty smell and thin white fumes coming out of it, so I lifted it off the boat and put it on the pontoon. I was wondering what had happened, and what to do next, when I noticed the smoke increasing - and looking blacker. It was clear the thing was on fire. So I did the obvious thing - lowered it into the water by it's power lead (flames were coming out at this stage) and made sure it was completely submerged before hauling it back up and putting it by the rubbish bins.

I've used that dehumidifier (and others before it) on my boat for years, because they keep the interior dry and fresh. Specifically I ran it from about October to February this year, before I took the yacht to the yard. Then within an hour of running it on our return - and it seemed perfectly normal - this happened. If our lift had arrived sooner, it would have gone on fire on the unattended yacht, and almost certainly destroyed it.

 

[anoccasionalyachtsman]

That's got me thinking, again. Too many reports of dehumidifiers taking things a stage too far.

Feel like naming the brand/model?

i'm going to have a look at mine and have a look at separating the useful components from the plastic housing and running it naked.

 

[Homer J]

What kind of dehumidifier was it please?

 

[Homer J]

Also did you regularly clean the filter? I understand that this is often where the problem is.

 

[Bobc]

That is precisely why I never leave shore power plugged in while I'm not on the boat, and never leave any mains electrical items running.

 

[Boathook]

That is precisely why I never leave shore power plugged in while I'm not on the boat, and never leave any mains electrical items running.

Me as well apart from the tubular heaters when I'm 'on board' and gone to the shops.

 

[xyachtdave]

I retired mine a couple of years ago, didn’t think risk outweighed the benefit. Glad the boat wasn’t damaged.

 

[Barnacle Bill]

It was a Dimplex domestic dehumidifier from a hardware store, model from a few years ago (pictures attached). Interesting idea to run one 'naked', but the fire in this case started on a small printed circuit board. Filter was not the problem (there isn't one on this model).

In the picture of the PCB, the unit is lying down with 'up' to the left, so it's clear exactly where the fire started.






So yes, the bottom line is that anything running with mains attached is potentially a fire hazard.

 

[anoccasionalyachtsman]

A decent brand - I was hoping it was going to be cheap import... I'll pursue the naked idea and write it up if it's feasible. (And doubtless get slammed for leaving dangerous voltages here there and everywhere for small children and kittens to lick).

Oddly enough I had a Dimplex fan heater melt it's plug (connected to an MK extension lead, so all theoretically good stuff) spring a smoke leak and threaten bad things, but fortunately a) on my workshop's concrete floor, and b) as I came back from lunch.

 

[mjcoon]

So yes, the bottom line is that anything running with mains attached is potentially a fire hazard.

Although a 12V battery can start a fire, too. Do you know what fuses should have protected the device?

Mike.

 

[DownWest]

The problem is that fuses tend to protect the cables from overheating. In the device, unless it shorts out or trips the earth detector, it doesn't take much power to start a fire. Had one in the house here. Melted the junction box, but luckily nothing combustable was close. Friends nearby were not so lucky. Lights went out, so he went to the main board and saw it was smoking, followed by flames. He decided to get his disabled wife out first, then called the Pompiers. They lost the house.

 

[Rappey]

Any non potted electrical item is at risk from damp and failure on a boat.
Do people not use deck ventilators any more?

 

[Wansworth]

I had a box that sat over the fore hatch this allowed a flow of air and n damp all winter,box can be put in the focsle for winter sailing and left at home in the summer.

 

[guernseyman]

With the best will in the world you were never going to dehumidify the whole river.

 

[LittleSister]

With the best will in the world you were never going to dehumidify the whole river.

No, but with good ventilation and you don't need a dehumidifier.

 

[RupertW]

No, but with good ventilation and you don't need a dehumidifier.

The only people who believe that have stopped noticing the pong when they open up their boat.

 

[Old Harry]

Any non potted electrical item is at risk from damp and failure on a boat.
Do people not use deck ventilators any more?

Dehumidifiers need a closed enviro to work effectively, vents allow damp air in

 

[LittleSister]

The only people who believe that have stopped noticing the pong when they open up their boat.

You are mistaken. There are various reasons for pongs, but not having a dehumidifier isn't one of them.

 

[Wansworth]

The only people who believe that have stopped noticing the pong when they open up their boat.

With my patent fore hatch box there was a very good drought through the boat exiting through the various grills etc and over the three years Ihad the boat it was closed up nine months a year.......no pong!

 

[LittleSister]

Dehumidifiers need a closed enviro to work effectively

?

vents allow damp air in

and out!

(And dry air in and out, too.)