Engine Room Blower

[Off Trail]

My engine compartment has a small (3" flex hose) blower system. The engine itself is a 4-cylinder Yanmar diesel. Although it functions, my owner's manual makes no mention of the blower, and I have never used it.

Am I making a mistake? Do I need to be using it during operation? If not, is it safe to remove from the boat?

Thanks for your thoughts.
Dan

[Sailmonkey]

Safe? Of course, you do t even need it.

But....you may find, that after motoring for a spell, that running the blower for 20-30 mins removes a bunch of heat that may have otherwise soaked that cabin. And, as your engine Ages...much like an old man....there is a smell. The blower can also pull that out.

[esarratt]

I debated having a blower then this information from Nigel Calder ended my internal debate: "Diesel engines require large amounts of air for combustion. Every hour, a small diesel is likely to draw in as much air as is needed to fill a medium-sized room.... If the air supply is restricted , it will lower efficiency...and shorten engine life." Pg 451 Boat Owners Mechanical and Electrical Manual

That cinched it for me.

[Bill Seal]

The engine room blower SUCKS air out of the engine room. The engine SUCKS air out of the engine room. If there's enough air being SUCKED out of said engine room to affect engine performance, I would suspect bulkheads would be bending inwards and the cockpit floor would start sinking..
The main thing a blower would achieve would be to lower the engine room temperature and keep the stink out of the cabin. If the blower is installed to pressurize the engine compartment, be prepared for stink.

[Cheechako]

Originally Posted by esarratt

I debated having a blower then this information from Nigel Calder ended my internal debate: "Diesel engines require large amounts of air for combustion. Every hour, a small diesel is likely to draw in as much air as is needed to fill a medium-sized room.... If the air supply is restricted , it will lower efficiency...and shorten engine life." Pg 451 Boat Owners Mechanical and Electrical Manual

That cinched it for me.

But which way did it clinch it? The engine room blower competes with the engine for air in theory!

OP: Keep it, you have a switch right? I used to run mine after motoring and while anchored for a while to remove some heat in lower latitudes.

[GordMay]

Engine compartment ventilation fans can suck, blow, or both (which I prefer).


We’ve had several excellent discussions, on this topic, including:

Engine Ventilation: Skip it?
ABYC Standard H-32 Ventilation Of Boats Using Diesel Fuel states:
"... power or natural ventilation is not required on a diesel boat, but may be used to control compartment temperature..."
The standard also provides guidance on other ventilation considerations such as supplying necessary combustion air, venting hydrogen gas from batteries when appropriate, and removing the discharge from fixed gaseous fire extinguishing systems.
➥ https://www.cruisersforum.com/forums...-it-37561.html

ABYC H-32 ➥ https://law.resource.org/pub/us/cfr/....H-32.1987.pdf

Engine room ventilation
➥ https://www.cruisersforum.com/forums...n-85829-2.html

Engine Room Blower
➥ https://www.cruisersforum.com/forums...wer-42656.html

Engine ventilation
➥ https://www.cruisersforum.com/forums...tion-7269.html

Engine Bay extractor fan
➥ https://www.cruisersforum.com/forums...an-158145.html

[Bill O]

We have our fan blowing out to remove the excess heat out of the engine room. Besides getting the heat out so it doesn't warm up the cabin, the alternator will function/charge better if the temp in the engine room is cooler.

[GordMay]

Originally Posted by GordMay

Engine compartment ventilation fans can suck, blow, or both (which I prefer)...

Gasoline engines BILGE fans suck.

ABYC H-2 Ventilation of Boats Using Gasoline
The ventilation system described in this standard is sufficient to provide for the requirements for ventilation of gasoline vapors from the engine space. However, the standard may not provide sufficient ventilation for heat dissipation.
➥ https://law.resource.org/pub/us/cfr/....H-02.1989.pdf

Ventilation cannot be relied upon to remove all carbon monoxide that may be produced from the operation of the vessel or its equipment. See ABYC TH-22, Educational Information About Carbon Monoxide, and ABYC TH-23 Design, Construction And Testing of Boats In Consideration of Carbon Monoxide, for further information.
TH-22 ➥ https://cdn.ymaws.com/abycinc.org/re...2_2017_Ref.pdf

[esarratt]

Originally Posted by Cheechako

But which way did it clinch it?

I'm installing a blower to suck in fresh air.

[GILow]

Originally Posted by esarratt

I'm installing a blower to suck in fresh air.

That’s confusing.

[sailormed]

Originally Posted by esarratt

I'm installing a blower to suck in fresh air.

So that is not a blower but a sucker

[GordMay]

Originally Posted by GILow

That’s confusing.

He's using 'blower' as synonymous with 'fan'.

[esarratt]

I thought my comment was rather smart!

To explain: My boat has two fresh air vents into the engine room on the sidewalls of the cockpit (see arrows). I am going to attach a hose, probably corrugated, to each of them. One hose will terminate down in the bilge below the engine (bringing in fresh air). The other hose will have a blower pushing air up the other hose out the other vent. Running the blower will create a suction effect through the first hose.

Thus, my blower is a sucker.

I have read that it is better to draw fresh air in to the engine room rather than to push fresh air into an engine room. The system will have a side effect of drawing in a little air from the cabin (around the engine cover seems) as well as drawing heat out of the engine room.

[Halifax Sailor]

My boat was repowered at some point from gas saildrive to yanmar diesel. There is an exhaust fan that draws from around the engine to a vent at the stern. I also have another vent open to the same area to aid in replacing the vented air. Working with large hvac systems in my past, you always need more supply air than exhaust in order for those systems to work so imo there must be sufficient if not more supply air in a boat. So I left the fan and use it after motoring distances to remove heat and any smell from the engine.

I also had an issue this summer where my exhaust elbow cracked, Only knew about it when my CO alarm when off. The fan removed the CO in less than 5 minutes (alarm went off) and I was able to run the engine enough with fan to haul my boat this year. No issues, all about safety. I will always keep mine just for what happened this summer.

[Wotname]

All blowers suck.
All suckers blow.

Ya can't have without the other