Bit of fun, maybe?

[snooks]

The first one is almost definitely a blower or sucker, depending one which way you look at it

Don't forget that diesel engines burn vastly more air than diesel, and this air has to come from somewhere. It will also help cool the engine space down (by either sucking cool air in or warm air out). Diesels, and their belts like cool air

It might only work when the ignition for the engine is on as you don't want the hummmmmmmmmmmmmmm of a fan whirring away when it's not needed.

 

[Murv]

An outside possibility is that the natural ventilation is insufficient for the air intake requirements of the engine, and this blower blows air INTO the engine compartment to make up the deficiency.

I suspect it's not that purely as the duct sits very low to the floor.
However, I wonder if it might be a help to do that? i.e if it does run as a "sucker," I could reverse the electrical connections so that it blows in and then remove the ducting so that the fresh air comes in at a useful height.
That way it would feed plenty of fresh air in, and, still blow out any gas build up as all the vents are on the stern.

A 2.5l engine at 4000rpm must be pulling a fair amount of air, 10,000l/min I assume!

The first one is almost definitely a blower or sucker, depending one which way you look at it

Don't forget that diesel engines burn more air than diesel, and this air has to come from somewhere. It will also help cool the engine space down (by either sucking cool air in or warm air out). Diesels, and their belts like cool air

It might only work when the ignition for the engine is on as you don't want the hummmmmmmmmmmmmmm of a fan whirring away when it's not needed.

Sorry, didn't see this when I posted, so I'm on the right lines then

 

[prv]

Diesel engines need holes to let air into the space, but I can't see any point to adding a small electrical fan. You already have a huge diesel-driven self-propelled air-pump sucking in all the air it needs.

If the engine was replaced nine years ago, was the original petrol? I don't think the blower looks necessarily more modern than that. If the old engine was petrol then it's almost certainly just a leftover.

The gash fencing eyes on the back could be anything, as they were clearly added by a cack-handed idiot

Pete

 

[Murv]

Diesel engines need holes to let air into the space, but I can't see any point to adding a small electrical fan. You already have a huge diesel-driven self-propelled air-pump sucking in all the air it needs.

If the engine was replaced nine years ago, was the original petrol? I don't think the blower looks necessarily more modern than that. If the old engine was petrol then it's almost certainly just a leftover.

The gash fencing eyes on the back could be anything, as they were clearly added by a cack-handed idiot

Pete

OK, thanks Pete.
I can't be sure, but am 99% certain that the original was Volvo Penta petrol.

The fencing eyes are in line with a fair bit of other work we've discovered around the boat!
It's not a priority, probably a summer job now, but I will remove them as they make the boat look tattier than it needs to.

 

[prv]

I can't be sure, but am 99% certain that the original was Volvo Penta petrol.

There you go then, that's where the bilge blower came from.

The fencing eyes are in line with a fair bit of other work we've discovered around the boat!
It's not a priority, probably a summer job now, but I will remove them as they make the boat look tattier than it needs to.

Cue fibreglass hole-filling instructions for your next post, then

Pete

 

[NormanS]

Just think for a moment what would happen in the unlikely event of having a blower fan which could deliver more air than you engine can consume. If you then have higher than atmospheric pressure in your engineroom, any fumes or smells of hot oil etc would be forced out of your engine space into the rest of the boat
The diesel is perfectly capable of drawing in all the air that it needs. The cold air helps to keep the engine and engine space reasonably cool.

 

[kelly-rose]

Any reason to remove it if it is still working? Some one obviously fitted it for a reason? Try living with it for a year and see. Could help reduce engine smells when engine is hot?

First year with boat I try not to change anything form previous owner they should know more about the boat than me...

That ok if it all works but we are finding alot of thing don't so we need to find out what everything does first so we can start replacing them

 

[prv]

Any reason to remove it if it is still working? Some one obviously fitted it for a reason?

Sure, and the reason was the large petrol engine that was fitted at the same time. Petrol engine now gone, no need for blowers.

First year with boat I try not to change anything form previous owner they should know more about the boat than me...

I agree it's best to use a boat for a season before designing "improvements", but I don't extend that to assuming previous owners necessarily knew better. This one, for instance, thought it was a good idea to ram a couple of B&Q's finest galvanised fencing eye-bolts through the transom

Pete

 

[Murv]

Cue fibreglass hole-filling instructions for your next post, then

Pete

Nope, you're safe for now, I have several pages of GRP repairs to refer back to from one of my posts relating to a cleat that has ripped out!

 

[Rossynant]

Definitely a bilge blower then, I guess I may as well remove it? Any reasons at all to keep it? (if it works!)

It better be working, there is probably a good reason to keep it.
It is not so that diesel will suck enough air into (from) the compartment. It will suck enough to work - provided there is big enough opening so the air can get there at all
Huge amount of heat is produced by this engine - you got a powerful one - and only some is taken out by cooling water. The rest heats the surroundings.
Now cooling system is for cylinders mostly, the rest of engine should be cooled by air around. Like oil sump, for instance. What if the air is hot? Some parts of engine will overheat. Automotive type engines are more demanding in this respect than traditional marine, as were designed to sit in the almost open with air blowing on them 50 mph or from a fan. They should also be fed with cold air as for efficient fuel burning - that is what 'intercooler' is for, sometimes.

Some engines on boats are fitted with additional oil coolers, and more, but still some parts are not cooled by oil. Alternator, for one. Belts. Those are air cooled and got to be provided with cool air.

Blowers are not always necessary for this, perfectly possible to make natural ventilation system - but then it's a rare a boat where engine space is not tightly closed and insulated to keep the noise down.
With insulating foam

Maybe it is worth to add the obvious: air not only should be fed into (or alternatively sucked out) - there should be the other opening so it can escape/enter. On the other side. Which way is another thing, for gasoline there is an issue of igniting the fumes, for instance.

 

[Murv]

Very good point, thank you, hadn't considered that at all.
Will check if it's working, and if not, will replace it.
The engine is certainly getting virtually no air cooling where it's sitting and it is a big old lump.

 

[Durcott]

Hi - if it's not too stupid a suggestion - perhaps those eye bolts were put there specifically to tie the boat cover to?

Jeff

 

[snooks]

Sure, and the reason was the large petrol engine that was fitted at the same time. Petrol engine now gone, no need for blowers.

Sorry not true. If it was true why do a lot of new boat mfgs fit engine blowers in their new boats with diesels???

To remove hot air which is bad for belts and engine economy.

 

[NormanS]

Sorry not true. If it was true why do a lot of new boat mfgs fit engine blowers in their new boats with diesels???

To remove hot air which is bad for belts and engine economy.

Or, as previously pointed out, to ventilate engine room prior to starting, in case of hydrogen etc.

 

[kelly-rose]

Hi - if it's not too stupid a suggestion - perhaps those eye bolts were put there specifically to tie the boat cover to?

Jeff

their is one at the front too so it could be