engine room temps/fans/waterspray

[vas]

following the hull speed thread that as usual in this parish has drifted a bit over the last week... I kept on thinking about engine room ventilation, fan extractors, humidity, stuck turbos et al.

So checking my craft, there are two largish (I guess) intakes 150X500mm on either gunwale pushing lots of air in the e/r.
There are 5 smallish extracts on each side (nicely designed typically Italian, doubt lots of air can be pushed through them though...)

There's no engine room fan anywhere I can see, no switch for them, nothing.

The engine with the stuck turbo is the port one, that has the airintake just in line with the port side intake (i.e. "outside" of the engine towards the hull)

I know LS says it's the exhaust riser (missing) hence seawater coming back into the turbo, but I feel that there may be a smaller possibly issue with the intake bringing lots of spray in, that is led straight in the intake, a water injection sort of thing

I wonder if I should add some type of deflector for the air, plus fit fans for the extraction (maybe at the last hole on each side) and a system comparing temps in and out to turn on the fans automatically.

What does the panel think?
Disclaimer, I'm going to sort out the engine exhaust anyway, so it's not a shortcut, just something extra...

cheers

V.

 

[Divemaster1]

........So checking my craft, there are two largish (I guess) intakes 150X500mm on either gunwale pushing lots of air in the e/r.
There are 5 smallish extracts on each side (nicely designed typically Italian, doubt lots of air can be pushed through them though...)

You mean similar to this ....

Never had any problems, and believe me, we have had a fair amount of water spraying over the boat....

Little chance of any large ammount of waterspray being sucked in like that, and if it had I believe :

1) water would evaporate as being heated up fast and salt sediments would be all over engine etc

2) If large amounts of water was ingested, then hydrolocking would occur (water don't compress very well), with predicable results of fatal engine failure...

Think I would lean towards LS's theory...

 

[rafiki_]

V, look inboard of the intakes. There should be some sort of baffle which allows any water to drop out before it gets anywhere near the engine. I have only seen US petrol boats without any baffles, and they have a more intricate air filter/cleaner.

 

[vas]

Alf, yes, I'm talking about them ducts (only I have five and you have a dozen on each side!)
I've not disputed LS argument, I'm just thinking if there's something EXTRA I should do

rafiki, I've removed the one gril from the gunwale, I need to do some proper digging to check if there's anything inside from the e/r. Also I need to check/remove anyway before painting the hull the ducts and see if there was/was meant to have an extractor fan somewhere in there...

cheers

 

[Divemaster1]

Alf, yes, I'm talking about them ducts (only I have five and you have a dozen on each side!)...........

V... those in the hull are very un-likely to cause any problem. If you have similar cowels like we do, then any ingress is very un-likely. Those intakes are more or less on level with the engine air intakes, and the trickle of water which may find its way in there will be subjected to the standard gravitational forces, and trickle down to the hull stringer below, which probably is drained at a central location out through a seperate hull fitting (ours are).

More chance of water ingress is from theair intake grilles in the superstructure.The grilles has drains, and the air duct leads down to same hull stringer as above ... well ours does...

You need pictures ?

 

[BartW]

Vas,
if spray was coming in these vents, your E/R would be full of white salt powder,
if not, no worry's

the Fans in the E/R,
I don't think you need these to cool the engines,
when engines running you have enough airflow from the engines sucking in lots of fresh air,

for me the only reason for the fans is not to heat the water in the tanks;
when I have stopped cruising with BA, the engine room becomes very warm / hot.
Two heavy Iron lumps at approx 80°C

if the engines cool down without the fans, it takes at least half a day before they reach outside temp, so the water in the water tanks will become much warmer.

when I switch on the fans after cruise stop, (which I occasionally do)
the fans will speed up the cooling of the engines, (don't know how much)
water tanks have less time to warm up.

temperature in E/R is less during navigating as my engines need LOTS of fresh air, sucked in by the engines, no fans needed for that.

I see no harm in a very slow cooling of the engines after navigation,
they won't become warmer then during navigation.

the lady likes that, for drying clothes and towels.

summery, I don't need fans in the E/R,
unless I want to have fresh water from the tap all day.

 

[Latestarter1]

following the hull speed thread that as usual in this parish has drifted a bit over the last week... I kept on thinking about engine room ventilation, fan extractors, humidity, stuck turbos et al.

So checking my craft, there are two largish (I guess) intakes 150X500mm on either gunwale pushing lots of air in the e/r.
There are 5 smallish extracts on each side (nicely designed typically Italian, doubt lots of air can be pushed through them though...)

There's no engine room fan anywhere I can see, no switch for them, nothing.

The engine with the stuck turbo is the port one, that has the airintake just in line with the port side intake (i.e. "outside" of the engine towards the hull)

I know LS says it's the exhaust riser (missing) hence seawater coming back into the turbo, but I feel that there may be a smaller possibly issue with the intake bringing lots of spray in, that is led straight in the intake, a water injection sort of thing

I wonder if I should add some type of deflector for the air, plus fit fans for the extraction (maybe at the last hole on each side) and a system comparing temps in and out to turn on the fans automatically.

What does the panel think?
Disclaimer, I'm going to sort out the engine exhaust anyway, so it's not a shortcut, just something extra...

cheers

V.

V,

Pay heed to the other guys posting here.

Properly designed air intake, fans not always requirement. Personal thing, but if I use fans they are extractors, keeps air 'calmer' in the ER, make sure air is drawn down in lower part of engine compartment. Think your vessel was a re-power, from the pigs ear installer made of the exhaust suggest you re-visit ER ventilation, likely never even thought about.

In previous post Delta T of 10 Degrees C was quoted, which is real good # to work to. From practical standpoint if you can squeak 17 C at WOT and then add fans to get lower, down to magic 10 Degree Delta you are in real good shape.
If you PM me with your email again I can send you comple set of installation guidelines.

Good luck.

 

[RustyClay]

go around the world
so it's not a shortcut, just something extra...

 

[vas]

I think we got out of track on this one and I have to apologise at it's my fault. I'll try to clarify.

as you can see in the pic above, there is an intake on each side high up on the gunwale level (I just measured it, it's 90X700mm)
There are 4 scoops or whatever you call them further aft almost level to the ceiling of the e/r, for extracting the hot air.

It's the intakes I'm slightly worried that maybe lots of seawater spray comes in underway on rough seas as there's a fair amount of spray all over tbh.
Futher since this intake is more or less channeling the air straight to the port engine air intake I was wondering if that can be causing problems. I know of another smaller sportsboat 33ft or so that had similar issues that were solved by simply fitting a deflector that led the fresh air further aft on entry.
Not checked for a baffle as yet, will report what I find tomorrow.

Regarding the outlets, a clear observation is that they are definitely MUCH smaller than the intakes! (talking sqcm area)
Further I've not seen any fans around, not that I searched much for them tbh, but will as I'm planning to spent the day there tomorrow.

So there are the facts.

I hope I'll get the time to remove the stuck turbo next week so that I get the exhaust elbow (not quite a riser) out, measure clearence, see what IVECO has to offer and they try custom. Not particularly keen on the big bugger boxes water traps or whatever they are called as it's an issue of space, cost and more space...
Yes it's a repower of a straight six DD with brand new IVECOs installed in 2000 (wrongly as LS pointed in the appropriate thread a few months back) by the IVECO Athens main dealer/supplier.
I do expect a fair amount of heat (have experienced it to a small extend due to the stuck turbo that meant all 300nm todate were at D speed and 1100rpm) although I bet the intake will act as an exhaust as well when engines are turned off. Water tanks are in mainly in the lazarette so shouldn't have a water heating problem there.
Not seen any salt deposits around the e/r, so seems I should be scrapping the whole issue and get on with my work, but may decide to fit extractor fans once I measure running/stationary dT.

LS PM is on it's way, thanks!


V.

 

[Divemaster1]

V...

Looking at the detail (stolen from one of your other posts);

Water will have to flow upwards and inwards to get through ... and what hits the baffle above and goes in,will run off the next one downwards etc., so suspect that not too much water will get in there. The water that may get in, should get trapped by some sort of drainage in the ER well before it gets near the engine's air intake. If you look at your picture, the intake in question is very near the front of the ER (Behind of Galley ... guess aligned with cooker and helm position from what I can see), as it is just above rear porthole of side cabin, whish stretches a bit behind that porthole from recollection.

That means that water have to;

1) Get in through the grid above
2) In to the front of ER
3) Travel about 2 - 3 Foot backwards to air intake whilst only dropping a short foot from ER Top level.

You may take in some water here, bus suspect your time (and money) is better spent on other work, and installing proper exhaust system as per LS advise...