Engine Room blowers

[Yachtsmyth]

We have 1 blower per E/R, that pull air out via a flex vent. Right now the flex goes straight down. Should this be along the ceiling of E/R? Would it be better to change these blowers out to force air into the E/R? Then the hot air could expel out vents?
Thank you for any advice.

 

[Pascal]

It is done either way.

Traditionally blowers pull air out of the air to remove gas vapors which doesn’t matter much on a diesel boat. By having the air pulled low with a duct, there will be some air circulation as air is pulled in thru the vents to replace the air being removed by the blowers.

Nowadays most builders of larger diesel boats use large AC blowers to force air into the ER and cool things down. Air goes out the vent... some even use variable speed blowers controlled by atmospheric pressure switch to force more air into the ER at high speed to feed the engines.

Downside of pushing air in the ER, especially on older boats where ER are not fully sealed is that you may force ER air in the living quarters

 

[Yachtsmyth]

Makes sense! Thank you.

 

[SEVEN]

When I had my boat surveyed prior to buying it the surveyor told me to take the hoses off because what you’re trying to remove is the heat. I did that and it seems to help.

 

[rwetherington]

the blower is meant to pull gas from the bilge if you had a fire and CO2 system went off it would pull the gas from the bilge and make it safe to return to the engine room.

Roger Wetherington

 

[Pascal]

Most if not all newer boats don’t use CO2 but the blowers are critical to keep things cool after a run. On the lazzara 84 i run, i have to set the blowers in manual mode and medium speed to avoid a high ER temp alarm (set at 120) These C32s generate a lot of heat!

 

[jmooney]

Our 61 has both ac and dc blowers , the dc hoses are down low by the battery boxes and the ac are toward the rear of the engine rooms and pull from the ceiling. They are small and I only use them after we dock and shutdown. They may not do much , but quite a volume of hot air is expelled rather than making its way upward into the salon and galley. I think to cool under way , a large intake and corespondent exhaust fan would be needed , probably at least 12 inches in diameter.

 

[JD5652]

On my 58 LRC I have four blowers in the engine room. Two of them pull air in and two of them exhaust air out. All four are 32 VDC.

I run the blowers continously underway to keep the ER cooler and for a while after docking for same reason. I find it keeps the ER about 10 degrees cooler.

 

[oscarvan]

One could very easily install a truck size radiator/fan with a circulation pump pumping seawater. Wouldn't be AC cold, but if the engine room is 120 the raw water would be at least 40-50º cooler in the warmest climes more anywhere else........

 

[Pascal]

You don’t really need blowers under way as the engines suck in quite a bit of air from outside the ER except a idle after a fast run.

I haven’t installed blowers in my ERs yet. The C series aren’t that big and don’t radiate a lot of heat. But when I install blowers it will be AC and probably extracting heat as the ERs aren’t sealed very well to the rest of the boat

 

[Westfield 11]

I have two blowers in each engine room. A forward one exhausting and an aft blowing in. I took the hose from the exhaust blower and secured it above the engine to remove air from the hottest part. That way there is a forced exchange of air in the engine rooms after shutdown. It seems to cool down faster with both fans running then with either of them alone.
When the engines are running the rooms are not too much above the outdoor temp from all the ambient air drawn in by the engines.

 

[bigbill]

just put new blowers and hoses, was thinking of mounting the hoses to the top of the engine rooms nearest the inside wall to remove heat. do y'all think a surveyor will flag the hose being mounted up high to remove heat instead of down low to remove fumes? also i am thinking of putting indicator lights by the switches to remind me that they are on. what indicator lights do y'all like, i would like led's if possible

 

[SEVEN]

As mentioned above my survivor told me to remove the hoses completely and use them to remove the heat.

 

[jim rosenthal]

I have the original DC blower which I seldom use, and an AC blower, much larger, on a one-hour timer, which I start up as soon as I dock and connect shore power. Usually I'll run it four or five time. Even the relatively small diesels I have hold a lot of heat in the small engine room of a 36C.

 

[Scarlett]

This Surveyor did the same thing to my boat that Rusty on Seven did, so no I don’t think a Surveyor would nail you for that unless you have gas engines. John