Engine Room Condensation

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larman

Senior Member
Joined
Nov 29, 2017
Messages
258
Location
United States
Vessel Name
Livin The Dream
Vessel Make
Sea Ray
I have my boat laid up for the winter and have been doing some work in the engine room and noticed a significant amount of condensation around the engines. The Marina does not allow space heaters, but I believe I am able to put a lightbulb in the engine compartment. Just curious will this actually raise the temperature enough to where condensation will not form? I’m on Long Island NY temps range 20-50 degrees approx during winter months
 
Every winter in NJ, I used a 40 watt incandescent bulb in a goose neck desk lamp aimed at my bilge pump to keep it from freezing. I usually added more lights in the ER and it seemed to keep it dry.
 
Raising the Temp. to prohibit condensation is too large of a question to answer.

I use a handful of fixtures constructed of a cement board base, an electrical box, a porcelain lampholder and an open ended Kirkland coffee can, suspended 1" above the cement board so it acts like a chimney. Total cost for each fixture including the wire was about $5. I run 60 to 250 watt incandescent bulbs in them depending on their location and room size.

A lampholder like this.

2 of them with 250 Watt bulbs in them keep my 15' x15' x 5' E.R. warm and dry.
2 of them with 100 Watt bulbs keeps my anchor locker (which is large enough to hold 2 people) from freezing in 10º F. Temps.

I'm not afraid of a light bulb burning out.
 
this reminds me of a single candle in a stranded car is supposed to keep you warm.
Yes back in the day light bulbs were used in engine spaces.
 
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Thanks for the replies, seems like the light bulbs maybe the way to go
 
Condensation is the process where water vapor becomes liquid. It is the reverse action of evaporation, where liquid water becomes a vapor. Condensation happens one of two ways: Either the air is cooled to its dew point or it becomes so saturated with water vapor that it cannot hold any more water.
Humidity gets higher as the temperature gets lower. Heat applied lowers humidity. The previous comment on the use of light bulbs (that provide heat) had to do with preventing freezing.
Condensation also forms on cold objects like windows in a hot room.

So why are you getting condenstaion without a heated ER? The ER air and engine block temp being the same should not cause condenstaion
 
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Condensation is the process where water vapor becomes liquid. It is the reverse action of evaporation, where liquid water becomes a vapor. Condensation happens one of two ways: Either the air is cooled to its dew point or it becomes so saturated with water vapor that it cannot hold any more water.
Humidity gets higher as the temperature gets lower. Heat applied lowers humidity. The previous comment on the use of light bulbs (that provide heat) had to do with preventing freezing.
Condensation also forms on cold objects like windows in a hot room.

So why are you getting condenstaion without a heated ER? The ER air and engine block temp being the same should not cause condenstaion
No idea, when the boat was shrink wrapped they covered the outside engine vents wonder if I uncover them will it help?
 
Are you allowed to use a dehumidifier ? Or is any electrical equipment prohibited ?
 
As @Portage_Bay pointed out, a Wolverine oil pan heater is a good way to go. It will put the heat into the entire engine and that in turn will keep the engine room warmish. The added benefit is faster starting and less smoke if your engines are mechanical. I have 250W units and they are connected to an inexpensive thermostatic controller and keep them on all winter.
Highly recommended.
 
He's getting condensation because the air temp in the bilge fluctuates. The air can hold more moisture at higher temps (the dew point is higher).

If the engine blocks are colder than the dew point of the air, condensation forms on the colder surfaces.

You can dry the air, or you can heat the space or the equipment such that none of the equipment is colder than the dew point of the air in the space.

A friend was adamant that engine block heaters "dry the air in the engine room." See above.
 
In my boat yard, you can not leave your boat plugged in. I use 4 Damp Rid around the boat. By spring time there about 1/2 to 3/4 full of water.

I just don't like leaving something on 24/7 anyways. I don't need a fire.
 
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they covered the outside engine vents wonder if I uncover them will it help?
Yep. I've had all the prior fixes over the years. They kind of work or at least can mask the problem. My prior owner had three different kinds of "wimpy heater" style of "dehumidifier." These warm the air up so that the relative humidity drops. When the air moves someplace cooler, the water vapor condenses again. Hopefully, it will be someplace where you don't see it and any damage is hidden. My prior owner used them in the cabin where the moisture then condensed on the bottom side of the cushions in the V berth. Actually inside of the material so that the mildew wasn't apparent. PO thought the problem solved?

The systems that use crystals also sort of work. I forget what the chemical is, but you can just buy the chemical (maybe calcium chloride?) at 1/10th the price. The issue is when you spill a drop (and you will sooner or later). It is almost impossible to get rid of. Kind of like The Cat in the Hat. That spot will stay wet/damp forever.

The best solution is ventilation and lots of it. If you have access to 120V, look into getting a 4" computer fan. Make a simple window/ER vent attachment that allows the fan to exhale. Fresh air will be brought in elsewhere around the boat. Quiet, but will probably do a complete air change in 24 hours. I've run them 24/7 for months on end. Electrical use isn't hardly enough to show on the meter. Probably less draw than the heater gizmos and it will actually work.
 
Be sure to give your engine or other metal parts a shot of WD-40 to help shed any water droplets. I also like the Davis "air dryer" and the Damprid ideas. I have three Davis units in my 30-foot boat right now as it sits in freezing weather clear of the water in its covered boatlift.
 
Air circulation is the ticket. light bulbs for heat is nice too if you have power. if not you can use DC fans and that will help a lot. You can run those off a small solar panel. .02 cents worth.
 
Hang a bag of damp rid in the engine room. Will keep everything dry and no chance of fire.
 
I have my boat laid up for the winter and have been doing some work in the engine room and noticed a significant amount of condensation around the engines. The Marina does not allow space heaters, but I believe I am able to put a lightbulb in the engine compartment. Just curious will this actually raise the temperature enough to where condensation will not form? I’m on Long Island NY temps range 20-50 degrees approx during winter months
See if can find a circulating water heater heater and install it in the engine cooling system
 
One of the things I've found that helps with condensation that can lead to mold & mildew is solar vents on my hatch covers. I use these (3). BTW, even if you are covered and the vents aren't turning, the opening will allow a flow of air.

Keep in mind that hot air rises and if you keep your hatch to your engine room open and crack a window that should help, while you are working in the boat to circulate air. It's the circulation that will help with your issues.

Another thing that I've found helpful, if it is really cold is a Dyson Hot/Cool fan. No exposed fan blades and you can set a temp for the fan to maintain. Here (Dyson Pure Hot+Cool™ Purifying Heating Fan HP01 | White | New - Walmart.com) is what I have. I would imagine that you have an inverter and could run the fan while you are onboard. Keep the temp down to a level that will make it comfortable to work but not hot.

Hope this helps.
 
I deal with this issue constantly in my industry, here is the solution we present to our partners:

Condensation forms on a surface when the surface temperature is equal to or lower that the Dew Point temperature.

The Dew Point depends on both the Air Temperature and the Relative Humidity in the space.

The formula to calculate the Dew Point in Fahrenheit is: Dew Point = Temperature - ((100-Reletive Humidity)/5).
You need to use the temperature and relative humidity inside the space for this calculation.
  1. Dew Point: The temperature at which the air becomes saturated with water vapor, causing water to condense.
  2. Relative Humidity: Higher humidity levels increase the Dew Point.
  3. Temperature Difference: The exact temperature difference between the inside and outside air that causes condensation depends on the Dew Point of the air in contact with the surface.
  4. Prevention: Decreasing the delta between the inside and outside temperatures via air exchanges (ventilation) is the most effective way to control the Dew Point inside the space.
It is counter intuitive but raising the inside space temperature without changing the relative humidity actually makes things worse. The best solution is constant air exchange between the inside and outside air.
 
Wow, I stopped reading all of the "opinions", sorry guys.
Some people were spot on, others?
Bob Cofer is spot on. Sealing up the boat is the worst thing you can do. Air exchange is the best, open your ER vents and try to work in the cold without heating. If the engine room and outside are the same temperature moisture with NOT condense onto cold surfaces.
 
Although ventilation can be used to reduce condensation it may not eliminate it.

Water condenses from the air when the water vapour in the air is said to reach the air's saturation point. To be considered saturated 70º F. air is holding about 70% more water by weight than saturated 40º air.

If you arrive at your cold soaked but ventilated boat for a day of work and you close the boat up, the amount of water in the air inside the boat is now basically fixed. As long as you don't boil pasta for lunch things are unlikely to change much.

As you raise the temperature of the air inside the boat the air's ability to hold water goes up and its Relative Humidity does down, which reduces the air's tendency to condensate.

Here is an article from the Museum Industry in Au. Museums need to keep things dry.


Have a read of just the first couple of paragraphs or so and then tell me why I need to work on the boat in the cold to stop condensation.
 
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Ok TJM, I'm confused, not that hard to do.

It was you that said "air exchange is best" and "work in the cold without heating" and when I challenge that opinion with a different plan, backed up by science, I get your thumbs up.

Has your opinion on working in a cold breeze changed?
 
I was trying to keep the solution out of the "technical weeds". You supplied more info and that is great. I am a liveaboard in Ct so I deal with condensation all of the time. In each room and on different days, I deal with condensation differently. Cooking, showers, your breath, propane heat all add moisture to the air.
The best solution is probably a conversation with the author.
 
I’m a fan of these rechargeable dehumidifiers:


We don’t get quite as cold, but I think they would work in your area too. Once they are full, you plug them in overnight to remove the moisture. A bit pricey at first, but after you recharge them a few times they are cheaper than the disposable sachets.
 
I was trying to keep the solution out of the "technical weeds". You supplied more info and that is great. I am a liveaboard in Ct so I deal with condensation all of the time. In each room and on different days, I deal with condensation differently. Cooking, showers, your breath, propane heat all add moisture to the air.
The best solution is probably a conversation with the author.
Adding moisture to the air is your nightmare. The best thing (in my opinion) to do in that instance is remove the moisture from the air. Any kind of desiccant (at reasonable quantities) just does not have the capacity to do the job required of a live aboard.
You need a compressor driven dehumidifier. Lots of options exist. The good thing is that all of the energy used by the dehumidifier while it is pulling water out of the air is returned to you as heat. Think about it, you get to enjoy the benefit of this energy twice, once as a drying agent, then once again as a heating agent.

Docktopus, really, the Eva -Dry E-500 is said to absorb 6 to 8 Oz. of water over a 30 to 60 day period. That is an eternity. My cheap $250 dehumidifier removes 6 Oz. of water in about 3 hours, which I pour down the drain. Then there is this, after say 30 days and the EVA thing is full, you plug the EVA thing in and it heats up to dry itself out.
Q.) Where does this 6 Oz. of water actually go? A.) Back into the air from whence it came. Perfect!

In the words that some attribute to P.T. Barnum, there is a sucker born every minute.
 
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