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Engine room ventilation

  • November 12, 2013 7:42 AM
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    Message # 1433435
    Anonymous member (Administrator)
    I'm working on reducing the noise when I run the engine in Pygmalion.

    I have a fan that runs when the engine is running that pulls air out of the engine room and into the cockpit.  I also have a 4" intake in the cockpit area for air intake.

    I'd like to have the fan run only when the engine room temp  is about 20 degrees higher then the ambient temp or ~90 degrees with a manual override on / off.  

    Questions are: 
    What does the fleet do about engine room ventilation?  
    Do you run a fan of any sort?

    I'm having a hard time finding a thermostat that is inexpensive and looks to work in the engine room. 

    Jay   
  • November 12, 2013 8:10 AM
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    Reply # 1433473 on 1433435
    Anonymous member
    Good question Jay, this is a project I have been thinking about for a long time now.
    My intent was to mount a mushroom vent in the triangle area behind the lazaret hatch ( but of course I haven't got up the courage to cut the hole!) and draw inlet air from inside the cabin. I had not thought of using a thermostat bit I like the idea... now to find one that will survive in the marine environment!
    Keep us posted with what you come up with.
    Steve







     
  • November 12, 2013 9:07 AM
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    Reply # 1433524 on 1433435
    Deleted user

    Jay, we don't do anything extra about engine ventilation and haven't had a problem.  Our home cruising  grounds here in the Delta are often in excess of 100 deg. and we saw hotter temps in in the summer in Mexico, with no ill effects that we can determine.  The motor is constantly pulling air in and exhausting it which may help but I'm not sure about that.  We have batteries in the engine compartment which lasted five years under heavy use and still tested good when we replaced them. If watermakers or refrigeration are in the engine compartment that would be a different story.  Membranes start to break down at 130 and over 100 degs. refrigeration starts to be effected. Engine ventilation is normally used for gas engines to vent before starting.  

    I'm more concerned about an extra hole allowing water in then I am about excess temp. In the bay area where you are I wouldn't worry at all about it.

    Johnson controls makes a small stand alone thermostat that would work and are available  where refrigeration parts are sold'

    Jim

     

    Last modified: November 12, 2013 9:13 AM | Deleted user
  • November 12, 2013 2:34 PM
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    Reply # 1433816 on 1433435
    Anonymous member (Administrator)

    Steve and Jim: 
    Well the owner likes the fan - and installed many years ago - ie the hole in the cockpit is already there 

    What do you think?  Seems like all the 12V versions are in Asia... in this case Hong Kong... May be just an on off switch would be enough per Jim's observations. 


    Wonder if a sensor is included... and mounted inside the cabin should be OK moisture wise.
    Last modified: November 13, 2013 7:05 AM | Anonymous member (Administrator)
  • November 12, 2013 10:12 PM
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    Reply # 1434084 on 1433435
    Anonymous member
    I had intended it to run when ever the engine was running... I wouldn't think the noise would be an issue. I know with the refrigeration unit in the engine room it gets hotter than it likes...
    Maybe someday!
  • November 13, 2013 9:34 AM
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    Reply # 1437412 on 1433435
    Deleted user
    Hello all -

    I just recently installed 'Yellow Tail' 3" blade fan to exhaust the engine compartment in our W42.

    The main impetus for the fan was a 50C battery temp trip on the charger control (while on float) on summer days with engine running.  Most battery mfgs state that you not exceed 50 C. My plan was to install the fan prior to installing new batteries.

    Our BETA 75 probably runs better with a cooler intake and while the hot engine provides warmth for the aft cabin hours after shut down a cooler engine compartment is desirable during summer months and to extend battery life. Alternators work better at cooler temps as well.

    Fan is on primarily when the engine is running (100 amp alternator) and consumes about 5 amps so I see no need for thermostatic control.

    The fan is surprisingly efficient/powerful and creates forced air ventilation of the engine room as there is an opening portlight in the same area. By closing the portlight the fan can also be used to exhaust the main cabin then thru the bilge area then engine compartment. 

    Problem with the fan is that it is annoyingly loud (the high pitch whine can be clearly heard near the exhaust outlet) and I am planning on moving the fan away from the exhaust to an enclosed locker in the engine room and routing the duct work to & from the fans new loaction.

    I purchased a VETUS plastic clamshell cowl to cover the hole in the outside of the cockpit coaming. A one way dryer vent flapper is installed in the exit hole to provide some protection boarding waves.

    Good luck with your project !
  • November 13, 2013 10:02 AM
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    Reply # 1437432 on 1433435
    Deleted user
    Great idea and to tell you the truth this is very easy to do. I could make a small circuit using marine grade (space and military grade parts) for very little expense.

    If you and others want a circuit I could make them -I am an electronics engineer who specialized in PID temperature controllers :)  and this could be done here on my boat. 

    I wont charge anything other than the cost of the parts. People have helped me and I feel obligated to help other Westsailors too. 

    Jay where is your vent mounted? I want to use a mushroom vent and just not sure where to mount it yet. I just hesitate because a wave could flood over it. Then again probably not a big deal. 

    Tom I had the same fan - actually two of them as they only lasted a few months. I did run them almost all day long and I agree they are very loud. I like the clam shell idea with the dryer vent something I may consider too. Thanks for sharing this. 
    Last modified: November 13, 2013 10:06 AM | Deleted user
  • November 14, 2013 5:07 AM
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    Reply # 1438128 on 1433435
    Anonymous member

    I have a solar fan in that spot aft of the lazarette that exhausts.  I also have one in an anchor rode deck plate at the bow blowing in. When cruising, I take the forward one out.


    No electricity needed.  
  • November 17, 2013 7:51 AM
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    Reply # 1440084 on 1433435
    Anonymous member (Administrator)
    I decided to split the difference and follow the KISS system and Jim's observations. 

    I did a slight rewire and the fan is now available from the power panel as needed.