Blowers: Bilge and Engine Room

[coopec]

I am currently working on the cooling system, exhaust system and fuel system for the engine but feel I should be considering the engine and bilge blowers at this stage too. (The blowers are certified to be "spark proof". I will solder cable joins and use heat-shrink)

I'll install the bilge blower down low but not too close to any bilge water. I'm not too sure where I''ll suck air from the "engine room". As I intend to use one Seabird Ventilator

View attachment 58105

I will use two butterfly back-draft preventers (as used in air conditioning) to stop the bilge blower exhausting into the engine room (and vice versa).

View attachment 58106

Before I go ahead and install them are there any do's and don'ts? Any tips would be appreciated

Clive

 

[prv]

Not commonly used here - maybe it's an Australian thing for the hotter climate? Otherwise the only place I've encountered bilge blowers is on small motorboats with inboard petrol engines, where they're used to evacuate any petrol vapour that may have accumulated from tiny leaks, to prevent explosion. Diesel doesn't explode, so the same risk doesn't exist on modern sailing boats or larger motorboats.

It's sensible to consider air intake for the engine; mine comes through a vent in the side of the binnacle, up over an internal dam forming something like a dorade box, then down through the same deck openings as the steering and throttle cables. But there's no active fans or blowers, the engine itself is quite a powerful suction pump.

It's often suggested that the incoming air should arrive in the vicinity of the alternator, as this is an entirely air-cooled machine that's the most in danger of overheating. The engine is water-cooled so probably doesn't care about the ambient temperature around it. Some other things might, for example if you have batteries, chargers, or substantial electronics installed in the engine bay.

Pete

 

[Greenheart]

No relevance to the OP's question, but it always occurs to me when I see bilge-blowers/ducting for sale, how many yachts' bathroom facilities would benefit from a pair...

...one to suck in fresh air at floor level, the other to evacuate steam and stinks through the roof. Big improvement on the inch of opening window which used to pass for ventilation.

If I fitted blowers for an engine-room, I'd also fit a diversion which could vent the heads at the twist of a valve.

 

[David2452]

I will solder cable joins and use heat-shrink)
any do's and don'ts? Any tips would be appreciated

Clive

Yes, don't solder cable joints on a boat, that should be reserved for panel work only. Use quality adhesive lined heat shrink covered crimp but connectors with strain relief either side of them.

 

[rogerthebodger]

I am currently working on the cooling system, exhaust system and fuel system for the engine but feel I should be considering the engine and bilge blowers at this stage too. (The blowers are certified to be "spark proof". I will solder cable joins and use heat-shrink)

I'll install the bilge blower down low but not too close to any bilge water. I'm not too sure where I''ll suck air from the
"engine room". As I intend to use one Seabird Ventilator

View attachment 58105

I will use two butterfly back-draft preventers (as used in air conditioning) to stop the bilge blower exhausting into the engine room (and vice versa).

View attachment 58106

Before I go ahead and install them are there any do's and don'ts? Any tips would be appreciated

Clive

I fitted blowers to my engine room but never used then as they are only needed for petrol engine boats. I have fitted air feed piped from outside into the almost sealed engine room to make sure the air input to the engine is as cool as possible and they is all i thing is nessary.

Currently on the boat where wifi is very iffy.

 

[syneraida]

Yes, don't solder cable joints on a boat, that should be reserved for panel work only. Use quality adhesive lined heat shrink covered crimp but connectors with strain relief either side of them.

Why no solder?

 

[MagicalArmchair]

There was a bilge blower installed on Triola when I got her ten years ago, one of these things: http://www.boatelectricals.co.uk/plastimo-bilge-blower/

In all my cruising life I had never come across one, so I unwired it (the ducting was all smashed up anyway). I've always been concerned that I should have left it in place - it MUST have been there for a reason... never suffered from overheating though on my 2GM20 after removing it...

 

[RichardS]

There was a bilge blower installed on Triola when I got her ten years ago, one of these things: http://www.boatelectricals.co.uk/plastimo-bilge-blower/

In all my cruising life I had never come across one, so I unwired it (the ducting was all smashed up anyway). I've always been concerned that I should have left it in place - it MUST have been there for a reason... never suffered from overheating though on my 2GM20 after removing it...

I'm sure you're right Mark.

I have one of the those Plastimo 16274 blowers in each of my 3YM30 diesel engine compartments. After replacing the brushes in one of the blowers this year, which was a logistical nightmare, I have now wired in a 12V relay with a toggle switch on the control panel so both blowers can be shut down when I feel that there is no chance of overheating or any fumes to be exhausted.

The blowers suck air out of the engine compartment which are not connected to the hull bilges.

Richard

 

[David2452]

Why no solder?

Creates a hard spot in the cable and can lead to fracturing, soldering (panel work aside) is now forbidden for those of us who work to ISO 13297

 

[coopec]

No relevance to the OP's question, but it always occurs to me when I see bilge-blowers/ducting for sale, how many yachts' bathroom facilities would benefit from a pair...

...one to suck in fresh air at floor level, the other to evacuate steam and stinks through the roof. Big improvement on the inch of opening window which used to pass for ventilation.

If I fitted blowers for an engine-room, I'd also fit a diversion which could vent the heads at the twist of a valve.

Thanks Dan

I already have a 170 cfm fan installed in the shower/head to suck steam/smells out of the shower/toilet and (rightly or wrongly) I am exhausting them into the anchor locker. I worry about the toilet/shower being sound proof too so I'm making an effort on that matter too. The fact the fan is a bit noisy is a plus as far as I'm concerned.

Clive

 

[coopec]

Yes, don't solder cable joints on a boat, that should be reserved for panel work only. Use quality adhesive lined heat shrink covered crimp but connectors with strain relief either side of them.

I'll look at that too, particularly in regards to the large bilge pumps I have yet to install.

Thanks.

Clive.

 

[coopec]

I fitted blowers to my engine room but never used then as they are only needed for petrol engine boats. I have fitted air feed piped from outside into the almost sealed engine room to make sure the air input to the engine is as cool as possible and they is all i thing is nessary.

Currently on the boat where wifi is very iffy.

The cost of a blower in the engine room is minimal. Although I am being very careful with the exhaust my concern is with running an engine in a confined space where people are. It would be lovely if the yacht was found at sea with all our bodies in an advanced state of decomposition and with empty fuel tanks!

Here is what one guy said when asked whether an engine room blower was required:

"And, make sure that the ventilator is open to the outside.
Further, if the suction end of the hose (intake) is at the bottom of the engine compartment, move it up near the top where the heat is, and reasonably close to the alternator. Run the blower any time the diesel engine is operating. Exhausting that hot air from around the block is a small (est. 5%) part of transferring waste heat from your engine, but still calculated in by the engineers. Engines and alternators do not like too much ambient heat."

Clive

 

[coopec]

Pete

The reason I want a bilge blower is because I have a LPG gas stove. If the yacht was a commercial vessel two gas detector alarms must be fitted as well (one in the bilge)

"The gas fitter wants to also install a bilge blower (which will ... Gas fitter now tells me, "no blower - no compliance, no compliance - no insurance".

Thanks

Clive

 

[coopec]

In all my cruising life I had never come across one, so I unwired it (the ducting was all smashed up anyway). I've always been concerned that I should have left it in place - it MUST have been there for a reason... never suffered from overheating though on my 2GM20 after removing it...

Your bilge blower was exactly the same as mine.

One Gas-fitter stated

"The gas fitter wants to also install a bilge blower (which will ... Gas fitter now tells me, "no blower - no compliance, no compliance - no insurance".

In Australia it is illegal for me to do any gas fitting in my home or my boat. Incidentally we use LPG in Australia but butane is also heavier than air and will collect in the bilges.

As far as the engine room blower is concerned temperature can get quite hot, even over the water, in Australia.

View attachment 58146

http://www.proboat.com/2015/06/venting-the-engineroom/

 

[prv]

The reason I want a bilge blower is because I have a LPG gas stove. If the yacht was a commercial vessel two gas detector alarms must be fitted as well (one in the bilge)

Ok, I can see a use for that. 99.9% of boats get by with an external gas locker and good plumbing to keep gas out of the bilge in the first place, plus a detector to warn if it does get in there. But if you're particularly worried about gas leaks then a bilge blower will add peace of mind, I guess.

In Australia it is illegal for me to do any gas fitting in my home or my boat.

I've heard about that, and similar for electrics, and always wondered what the guys way out in the bush are supposed to do?

http://www.proboat.com/2015/06/venting-the-engineroom/

Worth noting that that article seems to be about large engines on sportfishing boats, trawler yachts, and the like. Not a few tens of horsepower in a sailing boat.

Pete

 

[RichardS]

I suspect that there are big differences between small yacht auxiliary engines in a large space and large mobo engines in a small space, and between forced inlet ventilation and forced outlet ventilation, accepting that inlet and outlet are inter-connected and that, in extremis, both might be forced. I've no idea what the technical parameters are.

Now seen Pete's post .... we seem to be thinking along the same lines but he thought it first.

Richard

 

[coopec]

Pete

I have a gas locker under the deck with a drain over the side. (I also have the same for petrol on the Port side) I guess I am using the belt and braces approach.

As far as electrical work is concerned we are supposed to get an electrician to replace a fuse in the meter box of the house! But why do they sell fuse wire and Male/female 3 pin plugs to the general public? Most people I know would not be confident enough to wire up an extension cord.

Clive

 

[coopec]

I am convinced the "engine room" needs proper ventilation. (Mine is not big because it is under the center cockpit)

Starving' Engines Dying Sooner, Burning More Fuel

"Although the more air-hungry modern diesels are highlighting the problem now, it is actually not a new one. According to Marshall, older engines used to suffer, too; it was just less noticeable.'
“Older, lower output engines generally operate at lower speeds,” he says. “They struggled on so nobody really paid much attention to ventilation. In fact, many older designs didn’t have ventilation systems at all, they simply relied on the cracks in the floorboards to let in enough air!”
However, even those lower output engines were actually starving in many cases; the problem was just harder to spot.
- See more at: http://www.generalmarine.co.nz/News...Sooner+Burning+More+Fuel#sthash.LWD8hFq2.dpuf

Clive

 

[prv]

I am convinced the "engine room" needs proper ventilation.

It certainly needs a route for air to get in. I'm not convinced that a forced blower is needed in a yacht-sized installation because there's a 30-horsepower diesel-powered air pump sitting there already. Try putting your hand over the engine air intake if you don't believe me! But maybe there's some value to it in a hot climate - as much to get the heat out of the boat after shutdown as anything else.

Pete

 

[RichardS]

I am convinced the "engine room" needs proper ventilation. (Mine is not big because it is under the center cockpit)

Starving' Engines Dying Sooner, Burning More Fuel

"Although the more air-hungry modern diesels are highlighting the problem now, it is actually not a new one. According to Marshall, older engines used to suffer, too; it was just less noticeable.'
“Older, lower output engines generally operate at lower speeds,” he says. “They struggled on so nobody really paid much attention to ventilation. In fact, many older designs didn’t have ventilation systems at all, they simply relied on the cracks in the floorboards to let in enough air!”
However, even those lower output engines were actually starving in many cases; the problem was just harder to spot.
- See more at: http://www.generalmarine.co.nz/News...Sooner+Burning+More+Fuel#sthash.LWD8hFq2.dpuf

Clive

But with most of the examples we seem to be talking about the blower is sucking air out of the engine compartment and therefore tending to de-pressurise the compartment so starving the the engine of air even more?

Richard