[C320-list] Starting new chat about Engine vents

[Pat Tormey]

Just to confirm the Coast Guard regs specifically state blowers are required for gasoline engines.

Seemed like a good idea to check 😉

 

https://www.gpo.gov/fdsys/pkg/CFR-2008-title33-vol2/pdf/CFR-2008-title33-vol2-sec183-630.pdf

§ 183.610 Powered ventilation system.

(a) Each compartment in a boat that has a permanently installed gasoline engine with a cranking motor must:

(1) Be open to the atmosphere, or (2) Be ventilated by an exhaust blower system.

 

 

Pat

MMC #3555138

s/v/ Blue Skies
Newport RI

 

-----Original Message-----
From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Jeff Hare
Sent: Tuesday, February 6, 2018 10:33 PM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] Starting new chat about Engine vents

 

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> mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Scott Westwood

Sent: Tuesday, February 6, 2018 4:01 PM

To: Catalina List < <mailto:c320-list at catalina320.com> 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  <mailto:scottwestwood at bellsouth.net> scottwestwood at bellsouth.net H (919)-362-8538     C (919)-618-7185