Dehumidifier in the engine bay... good idea or waste of money?

[EugeneR]

Would a dehumidifer in the engine room, with extracted water going overboard via the bilge pumps, help keep engines in pristine, rust free condition?

Or will the heat encourage more rust and so on. Any other consequences?

I guess I need to seal the external vents to have any sensible impact.

Bilges are normally clean and dry so no issue with clean water going overboard.

Also, dehumidifiers are invariably for domestic use... insurance issue when in ER?

 

[jrudge]

In my experience stray spilt sea water is responsible for nearly all corrosion. I suspect there is a dose of salt spray involved as well.

I can’t see a dehumidifier would hurt, but do bear in mind a fair percentage of boat fires seem to have humidifiers as their source !

 

[rubberduck]

Engine room is ventilated so all you need is heating (I have tube heaters) & to keep salt water out.

 

[Sneaky Pete]

Give the engine a spray and wipe down every year with something like WD40 it will help repel moisture.

 

[dpb]

If you are discharging the water from the dehumidifier into the bilge below the engines for removal by the bilge pumps ( which on most boats dont remove all bilge water anyway) then the extracted water which ends up in the bilge is going to evaporate back into the air it has just been removed from whilst it waits for the level to raise enough to trigger the pump.
So not much point to the excercise, especially if you bilges are normally dry anyway..... unless ive missed something.

 

[jrudge]

Good point.

Why don’t they mount the bulge pump in a small recess so it does get the water out ?

My cranchi had a “ micro bulge pump” installed with a hose on. It was great you could get it all out without getting out the wet vac.

 

[simonfraser]

you can fit an AC condensation pump to the dehumidifier to extract the water to the outside if needed, guess it might freeze ....

 

[BruceK]

just plumb it into the shower sump

 

[EugeneR]

If you are discharging the water from the dehumidifier into the bilge below the engines for removal by the bilge pumps ( which on most boats dont remove all bilge water anyway) then the extracted water which ends up in the bilge is going to evaporate back into the air it has just been removed from whilst it waits for the level to raise enough to trigger the pump.
So not much point to the excercise, especially if you bilges are normally dry anyway..... unless ive missed something.

I wasn't sure of the relevant rates but would "dam up" the water around the bilge pump. If it can do 20 litres per day, surely it won't evaporate that quickly from such a small area? I don't know...

 

[A_8]

I used to do this and it worked great, kept the engine room very dry and engines rust free. Just make sure you stop the outside air getting in or it will be a waste of effort and energy. You can let the water drain in the bilges and also pump it out manually every now and again. The dehumidifier will take the water out of the air much faster than the drained water will evaporate back into it.