Should the engine bay blower be always on?

[Dockhead]

Originally Posted by svHyLyte

Ah...for the sake of the exercise...a diesel engine is an "internal combustion engine", no less so than a gasoline, kerosene or other fueled internal combustion engine whether reciprocating or turbine. To function, the fuel in an internal combustion engine must be "ignited" whether by a spark plug, glow plug or compression heating. If an engine utilizes an electrical power system for starting, the switch that activates such an "ignition" process, regardless of engine type, is nominally referred to as the "ignition" whether to simply activate the starter in a compression ignition system or to start and subsequently power the operation of a spark or glow-plug of that type ignition system. Non?

Never the less, if you prefer, by all means refer to the starter switch on you diesel(s) as whatever pleases you/fits you bill. Different ships, different long splices, Non?

Actually, I agree with Ron here. On old-fashioned gasoline engines, when you turned the key, you were actually powering up the spark ignition system. I still have (!) an old MGA, which has a key with only two positions, and only two wires -- one connected to the battery, the other to the coil. That's an "ignition switch", literally. The starter is operated by a separate pull-handle.

That's why we call it the "ignition". And it's wrong, in regard to a diesel engine, which doesn't have any ignition system at all. And probably in regard to a modern gasoline engine as well, since the "ignition switch" does not directly power up the spark ignition system.

[kas_1611]

Originally Posted by svHyLyte

Ah...for the sake of the exercise...a diesel engine is an "internal combustion engine", no less so than a gasoline, kerosene or other fueled internal combustion engine whether reciprocating or turbine. To function, the fuel in an internal combustion engine must be "ignited" whether by a spark plug, glow plug or compression heating. If an engine utilizes an electrical power system for starting, the switch that activates such an "ignition" process, regardless of engine type, is nominally referred to as the "ignition" whether to simply activate the starter in a compression ignition system or to start and subsequently power the operation of a spark or glow-plug of that type ignition system. Non?

Never the less, if you prefer, by all means refer to the starter switch on you diesel(s) as whatever pleases you/fits you bill. Different ships, different long splices, Non?

Makes sense to me and is possibly the best definition of a modern "ignition" I have heard.

If you think about it turning the key to position 2 or pressing the "on" button (as in my case) "ignites" the electrical system, a further turn to 3/Start or pressing the Start button simply activates the Starting system to turn the engine over until something inside goes BANG and the engine becomes self turning.

Keiron

[seabreez]

Originally Posted by epiic

Ever since I purchased the boat, the blower has never turned off when the engine is running. Is this normal?

The reason I am asking is because its starting to sound different and I am guessing it has more hours on it than it should.

My previous boat had the blower on a relay to shut off after a set period of time.

This is odd... if the blower was wired in a way that it does not shut off, there is a problem. Or maybe it was a mind set of the previous owner. The blower is made to evacuate noxious fumes or potential dangerous fumes from the bottom of the bilges. These fumes are normally heavier than air and can accumulate at the bottom of the bilges. After 4 or five minutes, the potential dangerous fumes should have been eliminated and fresh air has entered the bilges. You should start the blower when first stepping aboard to evacuated potentially dangerous fumes if any are present. The blower is explosion proof and should not cause a fire or explosion from switching this on. The other time where you should start your blower is immediately after fueling up. Now for your problem of why is the blower on all the time. Chances are is that there is not enough natural ventilation when the vessel is under way and possibly the fume alert comes on. The vents should be arranged so that more air is brought in than air that comes out of the engine room. Alllllll boats are setup so that half the vents bring air in and half bring the air out of the engine room. Substract the air that your engine breathes in to run... you do not have enough air in the engine room. To solve this... you should turn all vents, except one, towards the front to bring air in and the one exception should be turned towards the rear and with the hose all the way to the bottom of the boat and tied to pick up air 6 inches from the bottom. I have approached many manufacturers to have this redesigned and have been told that they do the building as per code. I then approached Transport Canada to address this issue and was told that they will look into it... never done. The bottom line... if you like your boat, your crew and yourself... do the modifications yourself. I welcome comments as this is a sore point for me as I have done thousands of boat inspections and have found thousands of discrepencies and many boat owners rely on the boat dealers to fix the problem under warranty and no dealers want to do the modifications. I welcome comments...

[SteveInMD]

I believe if you buy a new boat today it will come from the factory with a blower that runs at all time the engine is running. My 2016 is set up this way.

[boatpoker]

Originally Posted by seabreez

This is odd... if the blower was wired in a way that it does not shut off, there is a problem. Or maybe it was a mind set of the previous owner. The blower is made to evacuate noxious fumes or potential dangerous fumes from the bottom of the bilges. These fumes are normally heavier than air and can accumulate at the bottom of the bilges. After 4 or five minutes, the potential dangerous fumes should have been eliminated and fresh air has entered the bilges. You should start the blower when first stepping aboard to evacuated potentially dangerous fumes if any are present. The blower is explosion proof and should not cause a fire or explosion from switching this on. The other time where you should start your blower is immediately after fueling up. Now for your problem of why is the blower on all the time. Chances are is that there is not enough natural ventilation when the vessel is under way and possibly the fume alert comes on. The vents should be arranged so that more air is brought in than air that comes out of the engine room. Alllllll boats are setup so that half the vents bring air in and half bring the air out of the engine room. Substract the air that your engine breathes in to run... you do not have enough air in the engine room. To solve this... you should turn all vents, except one, towards the front to bring air in and the one exception should be turned towards the rear and with the hose all the way to the bottom of the boat and tied to pick up air 6 inches from the bottom. I have approached many manufacturers to have this redesigned and have been told that they do the building as per code. I then approached Transport Canada to address this issue and was told that they will look into it... never done. The bottom line... if you like your boat, your crew and yourself... do the modifications yourself. I welcome comments as this is a sore point for me as I have done thousands of boat inspections and have found thousands of discrepencies and many boat owners rely on the boat dealers to fix the problem under warranty and no dealers want to do the modifications. I welcome comments...

What accreditation do you have to support your " thousands of boat inspections" ?

Your Declaration of "all boats" systems is simply not the case.
and most of your ideas refer to gasoline engines only which are a large minority on this forum. Transport Canada TP1332E does have specific ventilation requirements fopr gasoline engines as does ABYC to which TP!##@ refers and defers.

[seabreez]

Originally Posted by boatpoker

What accreditation do you have to support your " thousands of boat inspections" ?

Your Declaration of "all boats" systems is simply not the case.
and most of your ideas refer to gasoline engines only which are a large minority on this forum. Transport Canada TP1332E does have specific ventilation requirements fopr gasoline engines as does ABYC to which TP!##@ refers and defers.

Trained by Transport Canada personnel for Coast Guard Auxiliary for 31 years ended in 2012 and now a Master 60 < Tugboat.

At the time of the inspections "all boats" I will qualify as 99.9% for gasoline 0.1 % diesel. For diesel engines... most starve for air, that is the reason there is excess heat in the engine rooms. Not enough air flow to remove heated air.

[boatpoker]

Originally Posted by seabreez

Trained by Transport Canada personnel for Coast Guard Auxiliary for 31 years ended in 2012 and now a Master 60 < Tugboat.

At the time of the inspections "all boats" I will qualify as 99.9% for gasoline 0.1 % diesel. For diesel engines... most starve for air, that is the reason there is excess heat in the engine rooms. Not enough air flow to remove heated air.

So basically counting life jackets.
Never seen aux. do a real inspection or inspecting ventilation systems at all and certainly not to TP1332 or ABYC. If you have done so, kudos to you.

[seabreez]

Originally Posted by boatpoker

So basically counting life jackets.
Never seen aux. do a real inspection or inspecting ventilation systems at all and certainly not to TP1332 or ABYC. If you have done so, kudos to you.

Thank you Sir... respectfully. Roger

[seabreez]

Originally Posted by svHyLyte

In the same manner as is the case on our boat, on the 409 the blower, mounted in the transom is connected to a vent tube that runs to the upper portion of the engine bay while two "static" (i.e. unpowered) vent tubes run from the transom to the lower area. The blower is designed to extract hot air from the engine bay and ensure the engine, while in operation, is receiving relatively cooler ambient air. That ensures the engine runs cooler itself and combustion is more efficient. FWIW there are rarely "unnecessary" parts on a boat. Most are included by the designer/builder to fulfill a specific, intended, purpose.

Here is a good example of a bad installation, (blower mounted in the transom and vent tube in upper portion of engine bay) Blower mounted perfect. Vent tube should be 6 " from the bottom.

[seabreez]

Originally Posted by SteveInMD

I believe if you buy a new boat today it will come from the factory with a blower that runs at all time the engine is running. My 2016 is set up this way.

I would really like to know the reasoning behind (running the blower when the engine is running). When underway you have natural ventilation that makes the running the blower redundant. What kind of vessel is your 2016?

[Pelagic]

Originally Posted by seabreez

I would really like to know the reasoning behind (running the blower when the engine is running). When underway you have natural ventilation that makes the running the blower redundant. What kind of vessel is your 2016?

I agree seabreez, you want to have versatility in controlling air movement in and out if ER for different reasons.

I think we can all agree that 99% of engines these days on cruising yachts are diesel, so any automatic venting for explosive petrol engines is not part of this discussion

For years I hired and worked closely with dutch contractor Heinan & Hopman
https://heinenhopman.com/en/yachting...ation-systems/
on specifying the systems and parameters for ocean going Superyachts

Key design criteria was for performance in both Arctic and Tropical conditions.

Maintain an ambient temperature at engine air intake for optimal engine performance.

Prevent salt saturated air from contamination of engine room in heavy weather.

Variable balance of Air in and Air Out at different engine RPM to maintain a very slight vacuum inside E.R. to prevent noise, smell and heat transmission to accommodation.

System to make engine room airtight in case of emergency requiring fire suppression

All of this required intelligent venting, reversible fans and training of engineers.

So you need to be able to turn your fans off or reverse flow when desired

[dlymn]

My diesel has a turbo and so it's 1500 cc motor draws more than 750mm a revolution. Let's say a litre per rev. At cruising speed of 2700 rpm that's 2700 litres per minute. That's 2.7 cubic metres a minute. That's about 7 times the volume of the saloon where the engine is every hour. In other words, with so much air being consumed by the motor and with an exhaust and cooling system that transfers much of the heat outside without heating inside, my guess is that engine rooms might not get as hot as we imagine. Even though I have 2x 3" inlet pipes and the same as outlets, well a pair at the front of the boat and a pair at the back, and one "outlet" has a blower, I wonder whether they actually work that way. My guess is that most of the air gets in through the bilge and gaps in the sole as well as all 4 pipes. I wonder whether much air actually gets out. There you go CaptTom.

[Terra Nova]

Originally Posted by Pelagic

...I think we can all agree that 99% of engines these days on cruising yachts are diesel, so any automatic venting for explosive petrol engines is not part of this discussion...

Not so fast.

Yachts commonly carry gasoline (for dinghy outboards), propane and batteries (which can give off explosive gases).

[Pelagic]

Originally Posted by Terra Nova

Not so fast.

Yachts commonly carry gasoline (for dinghy outboards), propane and batteries (which can give off explosive gases).

Do you store your gasoline and propane containers in the Engine room?

[Terra Nova]

Gasoline and propane fumes are heavier than air and so could wind up in the bilge or engine room.