Ventilation in the engine room

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Bladow

Member
Joined
Sep 20, 2020
Messages
15
Location
Decatur, Alabama
Vessel Name
CraSeaHorse
Vessel Make
HiStar Seahorse Trawler
What is the best / most reasonable blower for the diesel room (there are so many to choose from).
Thank you,
Susan & Kenneth Bladow
M/V CraSeaHorse
 
It depends:

Most engine room blowers are designed for gas engines where the blower is run for 10 minutes and shut off. If you plan to run it whenever the engine is running, and afterwards, most of the inexpensive ones won't last as a result of brush failure.

The second part has to do with how much pressure you need based on ducting. Many squirrel cage blowers lack the force / pressure as compared to the propeller style.

I went the inexpensive easy route with one that has good pressure. The Yellowtail worked well for me and generally last 1,100 to 1,200 hours. That was around a year or more. As I new it was a consumable, I kept a spare on hand. They have a 3 year warranty, but for about $40, I decided that I had gotten reasonable life for the investment.


Ted
 
That I have yet to see the need for engine room ventilation either betrays my lack of cruising time or applauds Mariner's native ventilation or Cummins cooling management. After several hours underway on a typical summer day, our engine room is warm, but hardly worth thinking about running the two fans that ventilate the space. Other than periodic testing, I've never run them. What am I missing?
 
That I have yet to see the need for engine room ventilation either betrays my lack of cruising time or applauds Mariner's native ventilation or Cummins cooling management. After several hours underway on a typical summer day, our engine room is warm, but hardly worth thinking about running the two fans that ventilate the space. Other than periodic testing, I've never run them. What am I missing?
You might have enough natural draft ventilation and a big enough engine space on your boat relative to the heat produced by the engine to keep things at an acceptable temperature without the fans running.
 
The 37 has a very roomy engine room and it is contiguous all the way to back to the lazarette bulkhead. Among my favorite traits of the model. Perhaps lucky on fan wear too!
 
Delta T, I believe, makes some heavy duty ventilation equipment. But it is dear.
 
I only run my blowers after I turn the engines off. They self ventilate the space with all the air they draw in to run. I have a wireless thermometer in there and the space never exceeds 110F when running.
 
Larger Sea Ray's back in the early 2000s had large 12V fans on both sides of the engine room on the inside of the normal ventilation openings.

I suspect they were similar to electric automotive radiator fans and their ability to stand the harsh environment. They worked well, especially after shutting down and cooling the engine room versus it heating up the salon space.

You may try contacting a Sea Ray dealership and see if they have at least an old part number for them.

I am assuming you don't mean typical USCG ventilation style vents, if you do, pick ones that can turn over a lot of air (calculate your engineroom volume versus about a 5 minute turnover and mount high without normal USCG ducting as I believe you don't need it for diesels.
 
That I have yet to see the need for engine room ventilation either betrays my lack of cruising time or applauds Mariner's native ventilation or Cummins cooling management. After several hours underway on a typical summer day, our engine room is warm, but hardly worth thinking about running the two fans that ventilate the space. Other than periodic testing, I've never run them. What am I missing?
Well, when we run our Cummins generator our engine room is over 100* and of course the hot weather hasn't helped.
 
That I have yet to see the need for engine room ventilation either betrays my lack of cruising time or applauds Mariner's native ventilation or Cummins cooling management. After several hours underway on a typical summer day, our engine room is warm, but hardly worth thinking about running the two fans that ventilate the space. Other than periodic testing, I've never run them. What am I missing?
Might be a function of where you cruise. 😉 Seriously, without a thermometer, it's hard to know how warm your engine room is getting. If I were staying under 100 degrees Fahrenheit, I probably wouldn't worry about it. As temperatures get higher, fuel and engine intake air aren't as efficient. At the end of the day, if you need air conditioning, not having a 130 degree engine room certainly makes it easier to cool the saloon.

Ted
 
At 1600 rpm where I generally run the two 5.5 liter engines will pull in 300 CFM, which is essentially a complete engine room air change every 2 minutes. You open the access door when running and you can feel the breeze going by.
 
Given the high amounts of air that the Cummins QSB engine sucks in, I really don't worry about having adequate ventilation while under way. However, on hot days I will at times turn on the blower after shut down and let it run while I am putting the boat to bed.

Given the large amount of heat sink represented by the 5.9L engine, that probably isn't enough to make a lot of difference. I have considered putting a timer on the blower so I could let it run for an hour as I leave the boat.
 
May depend on the engine(s) you have. My Jimmies ventilated the ER like a mutha, but 2-strokes are equipped with blowers and push huge volumes of air. The only time the ER was uncomfortable hot was after engine shut down, and then you'd want huge volumes of air, for a few hours, to cool those big blocks down. The heat didn't bother me, but I had FLA batteries. If you run lithiums then that might be another matter, but you may wish to consider relocating those to outside the ER.
 
Airflow from the engines themselves definitely varies a lot. On my boat, the engine room temp will actually drop a couple degrees if you throttle up and get on plane compared to running at slow cruise due to the extra airflow (and the engines draw from up high in the engine room). It's a gas boat, so the blowers draw from down low an don't provide a lot of cooling.

I've been working on changes to the non-powered vents so that some of mine are ducted to the top of the engine room and some to the bottom (originally all went to the bottom). I'm hoping this will give a bit better cooling by stirring up the air more as air is drawn in, and after shutdown it should pull heat and engine smells out better as the hot air rising to the top should rise out of the vents and start to pull cool air in through the other vents.
 
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