[C320-list] Starting new chat about Engine vents

[Jeff Hare]

That was my suggestion earlier back when I first did it.  I thought it would
be a good idea, but it was so loud it was just impractical.

Instead, I considered reusing the blower switch for a light or some other
purpose in that back locker since it was already wired there.  The main
drawback to the blower that for some of us with dedicated starting batteries
is that the power feeding the engine pod/blower is from the starting
battery, not the house bank. It would take a little rewiring to get house
bank power up in there.  So there's yet another reason my blower is destined
for the basement.

-Jeff

-----Original Message-----
From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf
Of Graeme Clark
Sent: Wednesday, February 7, 2018 2:26 AM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] Starting new chat about Engine vents

Great ideas Jeff

I had heard an alternative suggestion somewhere, to keep the blower but
shorten the hose so it sucks air from the fridge compressor area to help
cool it

Seems a reasonable idea apart from noise and yet more current drawn off the
batteries!
Graeme



Sent from mobile: please excuse typos etc.!


> On 7 Feb 2018, at 03:33, Jeff Hare <Catalina at thehares.com> wrote:
> 
> Here's the rationale behind my choice, and I'll bullet them a bit.
> 
> 1. USCG regulations I've seen say a Bilge blower isn't required for a
diesel engine anymore.  The one on the 320, especially with how it's
installed, doesn't move enough air in practice to really vent much of
anything out of the engine space. Especially using those restricted dryer
vent hoses.  And also it's embarrassingly loud and obnoxious as heck when
running.
> 
> 2. If you look at that aft locker space as a whole, the air intake on the
engine mostly draws fresh air through the path where those white hoses run.
The bulk of the air feeding the engine probably doesn't come through those
undersized hoses at all. The one that was supposed to be used to feed air to
the engine is the one connected to the starboard side vent.  That long bendy
path to the starboard side vent is pretty useless for that purposes.
> 
> 3. If you were to look at the resistance involved in sucking air through
those bendy collapsed hoses, you'd realize that air would flow more freely
to the engine without them at all.  
> 
> 4. The Aft locker area is also where the fridge compressor is. If you run
your fridge a lot,  that area heats up and makes the compressor work harder
than it would if it had fresh air available. That's why if you slightly prop
open the port aft locker and vent the heat from the fridge, it'll run a bit
less.
> 
> 5. Removing those hoses reduces clutter.
> 
> So: I figured, why not make these systems work as efficiently as we can by
allowing compressor heat to rise and exit the vents on their own without any
hoses blocking the vents.  When the engine is running, fresh air will be
drawn in through the vents and cracks, pass through that aft locker, under
the port locker where the white hoses used to run and into the engine.
Since the engine draws quite a bit of air, it'll maybe draw some of the
excess fridge heat with it as well.  
> 
> I'd clamp a scrap of window screen over the inside of the vent holes will
keep the critters out without being overly restrictive for airflow.  I did
all this when I replaced my fuel tank and it cleaned up the appearance of
that space quite a bit. 
> 
> To answer your other questions:
> 1) Yes we leave the aft berth boards and bed in place when motoring.  In
fact, I would advise that you not run the engine in gear with the board
directly behind the engine off.  The spinning shaft can spray a line of
mist/water that could mark your ceiling in some cases.  Look at your muffler
right in line with where the shaft enters the stuffing box and see if you
see evidence of any spray line. The PSS shaft seal left a black line on ours
from carbon/water and it's also on the underside of that board.
> 
> 2) A CO sensor is a wise choice, especially since we have a propane stove.
While CO isn't quite as big a concern with diesel exhaust as with gasoline,
diesel exhaust still dangerous if there's a exhaust leak and a CO sensor in
the aft cabin is wise.
> 
> -Jeff Hare
> 
> 
> 
> -----Original Message-----
> From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf
Of Scott Westwood
> Sent: Tuesday, February 6, 2018 4:01 PM
> To: Catalina List <c320-list at catalina320.com>
> Subject: [C320-list] Starting new chat about Engine vents
> 
> I saw Jeff's comment about the engine vents and those bendy hoses.  I just
redid my engine instrument panel and replaced the Blower switch.  Have not
re-installed the panel yet so I have no idea if the blower even works.  So
this means I have not really been "venting" the engine compartment at all.
Does not seem to have been any problems (so far- knock wood).  I was
planning to go over all that once I got the panel back in place.
> Are you saying that you took out those (we have) white flexible hoses that
seem brittle to me.  It sounds like you (Jeff) removed the hoses and put
screen (for critters) over the stern holes??  Do you run the engine with the
aft berth boards all in place?  Do you leave anything else open?  Or... does
the engine compartment vent enough with all the covers on??
> FWIW.  We plan to (have not been) keep a battery operated Carbon Monoxide
sensor with us on the boat just as a safety feature.  Portable and you can
take it along with you anywhere. Thanks, Scott Westwood
scottwestwood at bellsouth.net H (919)-362-8538     C (919)-618-7185 
>