[C320-list] Air duct to engine

[Marek Fluder]

Jeff,

You have confirmed my observations and gave a good suggestion to re-purpose.
Just wanted to say thank you for your valuable info.

Marek
#1028


On Mon, Jul 27, 2015 at 4:45 PM, Jeff Hare <Catalina at thehares.com> wrote:

> Hello,
>
> These hoses are essentially worthless.  You'll have FAR better airflow to
> the engine if you simply remove them and perhaps put a piece of screen over
> the inside of the intakes that are mounted on the transom.  These little
> hoses are too small for the run length, kinked, rippled inside, make tight
> bends, have zip ties squeezing them and probably have junk sitting on them
> further reducing the airflow.  When they're connected to the vents, that
> means very little air gets in or out of those vents without finding a way
> through the hose.
>
> So, the one that connects to the "fan" is the Bilge Blower.  This blower is
> installed at the factory because, who knows, there might be someone left
> who
> thinks a diesel needs a bilge blower to keep the diesel fumes from
> exploding
> while starting your engine. Makes sense with gasoline engines though.
>
> So, here are a few different suggestions.
>
> 1.  Ditch the hoses completely and use bug screen over the openings.  This
> will allow the engine to suck in as much as needed, easier and with less
> restriction.  It will also allow the heat from your refrigerator compressor
> to exit through those vents and will be more efficient and keep that aft
> locker cooler.  With the bilge blower connected, that vent is highly
> restrictive unless the blower is running.
>
> 2.  If you're one of those who think the bilge blower is useful for cooling
> down the aft cabin.   I did an experiment using my little graphing
> thermometer in the aft cabin after motoring for several hours 3 years ago.
> Try it yourself.  The aft cabin didn't cool down one bit faster with the
> bilge blower running for 30 min than it did without the bilge blower
> running
> at all.  And my ears felt better.  But if you still want them, replace the
> dryer hose with 4" smooth wall hose used for dust collection and now,
> you'll
> get more airflow, but not as much as if you simply remove the hoses. You
> can
> quiet your bilge blower a ton by mounting it on a thick layer of neoprene
> to
> isolate it from the mounting brackets.
>
> 3) If you simply must have these hoses, leave the hose to the bilge blower
> next to the fridge connected, but cut the hose so that it ends right in
> front of your fridge radiator and use the bilge blower to vent the heat
> your
> fridge compressor generates.
>
> USCG doesn't require bilge blowers in diesel powered boats any more.
>
> My opinions of course.
> -Jeff
>
>
>
> -----Original Message-----
> From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf
> Of Graeme Clark
> Sent: Monday, July 27, 2015 4:02 PM
> To: c320-list at lists.catalina320.com
> Subject: [C320-list] Air duct to engine
>
> On the transom there are two air vents, one is the exhaust vent of the
> extractor duct from the engine compartment running through the electrical
> fan*
>
> The other is - on my yacht - a long white plastic duct which terminates in
> the aft locker space, under the rudder cables just lying on the floor!
> I suspect this is not where it should terminate!
>
> I have a nasty suspicion that the previous owner may have tampered with it
> whilst installing the ducting for a cabin heater but I'd sure like to know
> where it's supposed to go and what it does, as everything seems to work
> fine
> at the moment!
> Thanks
> Graeme Clark
> #366, Jaskar
>
> (*By the way, the fan will only switch on if the ignition is switched on.
> This means if the engine isn't running I get the low oil pressure sounding
> which if I run it for any length of time, annoys neighbours! Any reason I
> can't rewire  it to a different live source?)
>
>
>