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Author Previous Topic: How have you mounted your Baby Q? Topic Next Topic: NauticStar boats?  


RO# 362

Posted - Jun 13 2018 :  21:49:28  Show Profile  Reply with Quote
I want to be sure of this answer. Are blowers always blowing air out of the engine room regardless off if itís gas or diesel? Thanks.

Homeport: St. Louis


RO# 7269

Posted - Jun 13 2018 :  22:46:01  Show Profile  Reply with Quote
Not to be a smart ass, but blowers suck the air out of the engine room-but your question could be a matter of perspective depending on which side of the blower you are on. On gassers, you want to get any explosive fumes out of the engine room. With diesels, explosive fumes are not the issue, however you want to draw cooler air into the engine room for more efficient combustion-the same would go for gassers I would think. I always run my blowers from pre-startup to at least 30-60 mins. after shut down to pull the heat out of the engine room which allows the A/C to cool the cabin faster at the dock.

The only thing that works on an old the Owner.

Homeport: Clearwater/St. Pete Florida Go to Top of Page


RO# 1933

Posted - Jun 14 2018 :  07:49:02  Show Profile  Reply with Quote
Diesels are nothing but air pumps, so no need to run blowers while operating the engines. Just use afterwards to cool down the ER. On most larger boats, the blowers blow cool outside air into the ER.

65' Pacific Mariner
"Travis McGee"
Plantation Yacht Harbor
Islamorada, Fla. Keys

Homeport: NASHVILLE, TN Go to Top of Page

Brite Idea

RO# 12714

Posted - Jun 14 2018 :  08:17:00  Show Profile  Reply with Quote
My mechanic advised me to run my blowers whenever the engines are running to keep the heat down. I have been doing this for 15 years and so far so good. I've been in the engine room of a big twin engine diesel boat while underway and I think the blowers would run backwards those engines are beasts!

Homeport: Copiague, N.Y. Go to Top of Page


RO# 12212

Posted - Jun 14 2018 :  08:51:43  Show Profile  Reply with Quote
On gas boats the blowers pull air out, using duct mounted low into the bilges to get the heavier than air gas fumes out

On diesel boats it depends on the set up. Some smaller diesels are set up like gas boats but usually as they get bigger blowers are set up to pull fresh air into the ER. In that case bilges and wire chases need to sealed so ER air doesn't get pushed into the rest of the boat.

Some boats can be set up with variable speed blowers (240v with frequency drives) and atmospheric pressure sensor to regulate speed. The faster the engines run, the faster the blowers push air in the ER.

1970 Hatteras 53 MY
26' Starfish sloop
12' Westphal Catboat
16' Hobie Cat
13' Sandbarhopper

Homeport: Miami, FL Go to Top of Page


RO# 12640

Posted - Jun 14 2018 :  18:25:53  Show Profile  Reply with Quote
Silverton 45C D9 Volvo Motors (Diesel) Should I run my blowers all the time?


And always remember, life is not measured by the number of breaths we take, but by those moments that take our breath away.

George Carlin

Homeport: Go to Top of Page


RO# 1159

Posted - Jun 15 2018 :  00:40:46  Show Profile  Reply with Quote
Originally posted by walterv

Silverton 45C D9 Volvo Motors (Diesel) Should I run my blowers all the time?


On diesel boats, some operators do run all the time which in most cases I should think is quite unnnecessary, and some do not run them at all , or even have any blowers.

IMO (pretty worthless- I have gassers), it mostly depends on how effective your passive ventilation system is, and a bit on how hot the ambient air is and how much breeze there may be to help swap air.

But I'd recommend really inspecting the active and passive ventilation system on any boat. I'd venture as only a WAG maybe 1/4++ or so of somewhat older recreational boats with such systems have at least some deterioration or full separation of duct hoses and/or perhaps an unnoticed inoperative blower if there are more than one.


Edited by - Sandy on Jun 15 2018 00:43:16

Homeport: The Vineyard Go to Top of Page


RO# 3238

Posted - Jun 15 2018 :  01:37:31  Show Profile  Reply with Quote
I've found that the "Boatbuilder's Handbook" is an excellent source for guidance on this subject.

Main page:

Chapter on ventilation:

In theory, your boat's ventilation should not need to rely upon powered ventilation while operating ( for most boat designs ).

I refuse to comment on the various manufacturer's interpretation of these rules, however. If you feel less confident of the design, then I suppose that continuous operation might be an answer.

But, frankly, the air ingested by an ICE while operation should be plenty to provide the required ventilation, and powered ventilation only needed when the passive systems are "below operational minimums", such as prior to engine start, idling at the dock, or cool down after operation. IMHO.

Your boat. You are the Captain. Whatever the Captain sez...


"No matter where you go, there you are." -- Buckaroo Bonzai
"There is nothing, absolutely nothing, half so much worth doing as simply messing about in boats." - Kenneth Grahame

Homeport: MS Gulf Coast Go to Top of Page


RO# 7334

Posted - Jun 15 2018 :  09:05:21  Show Profile  Reply with Quote
I highly recc Running the blowers after use. THE ER GETS STUPID HOT. That heat takes its toll on everyting rubber. Regardless of what the manufacture says ,.

I run the blowers and raise my hatch when possible . 4" fan is like pissing in the wind


2006 44 Sundancer

Homeport: Merrick, NY Go to Top of Page

Gregory S

RO# 2620

Posted - Jun 15 2018 :  09:52:47  Show Profile  Reply with Quote
just don't run them while you are re-fueling! can't tell you how many times I've seen that.

Homeport: Norfolk, Va Go to Top of Page

L. Keith

RO# 1615

Posted - Jun 15 2018 :  09:56:19  Show Profile  Reply with Quote
Diesel engines operate more efficiently in a positive pressure environment. A proper machinery space should be at 1-2 PSI above ambient. The positive pressure in the machinery space means less effort for the engine in drawing in the combustion air. Less effort at air intake means more power available for output. The cooler the machinery space the more efficient your electric motors and other electrical devices. That is why generators get down rated in hot/warm spaces.

Homeport: N. Gulf of Mexico Go to Top of Page


RO# 842

Posted - Jun 16 2018 :  08:47:10  Show Profile  Reply with Quote
I only ran the blowers when the diesels were shut down in order to cool the er faster. The airsoops found on smaller gas boats dont seem to be installed on diesels. They wouldn't hurt but probably are too small for the massive amount of air diesels move. I have seen large fans into the ER of larger diesel boats


Homeport: Gulf Coast FL Go to Top of Page


RO# 3300

Posted - Jun 17 2018 :  19:43:23  Show Profile  Reply with Quote
Engines of either flavor run more efficiently inhaling cool/humid air, just like when it's raining though now a days, gas engines are designed to run most efficiently at higher cars, which is too hot for boats.

I run with blowers on whenever the engine is running. On hot days, I'll open the engine hatch after a run, and sometimes I'll open the hatch WHILE running


There is much to be said, in a world like ours, for taking the world as you find it and fishing with a worm.-Bliss Perry, 1904

Homeport: Ca Go to Top of Page


RO# 12527

Posted - Jul 10 2018 :  12:05:51  Show Profile  Reply with Quote
I cannot figure out why they say do not run your blower while pumping gas, I understand that it may encourage a little bit of gas fumes but hardly enough to cause an explosion, you would have to be spilling it all over your boat to create that much vapor. Especially because I know that my air exhaust is on the same side of the boat as my gas opening. But it makes more sense to me to run the fan as youíre not getting the initial power spark when youíre done pumping because the fan is already on. I donít see an average boater waiting 5 minutes on a crowded dock for the blower to blow for 5 minutes anyways..

Homeport: Babylon,NY Go to Top of Page


RO# 12212

Posted - Jul 10 2018 :  12:13:18  Show Profile  Reply with Quote
That s because IF the intake vents are close to the fuel filler or the fuel tank vent the air sucked in could bring in fumes

Thatís why gas fumes detector are so critical

1970 Hatteras 53 MY
26' Starfish sloop
12' Westphal Catboat
16' Hobie Cat
13' Sandbarhopper

Homeport: Miami, FL Go to Top of Page


RO# 14

Posted - Jul 10 2018 :  21:50:50  Show Profile  Reply with Quote
I adhere to the guideline of not running the blowers while fueling. I also run the blowers immediately following until I pay and return to the boat. I also take the final precaution of pulling open my rear floor opening to inspect the bilge, but in my boat's case that is very easy to do. I know people won't do that if they have to remove seats or crawl through from the cabin.

Homeport: Matts Landing, NJ Go to Top of Page
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