[C38] Vented loop. sea water cooling intake

[Max Soto]

Ups! Pressed send without having finished the message!!!

> Don, 
> According to the Catalina drawings, That is the original vent location for the C38. 
> I'm with Steve O  on the vented loop issue.  This vent is supposed to avoid flooding of the muffler and then the engine when you turn it off. 
That's why it needs to be located in the hose right before the elbow riser. 
I wouldn't use it before the saltwater pump. That could bring some new and unexpected problems....
Max

> 
> Sent from my iPod
> 
> On Nov 5, 2011, at 8:17, Don Strong <drstrong at ucdavis.edu> wrote:
> 
>> Steve: 
>>     Thanks for thinking about me. Yes, the vented loop is is at the top of a hose run of about 2.5 feet straight up from the seacock that brings in the sea water for engine cooling. The hose then runs from the loop to the cooler.  The loop is screwed to the bulkhead at the forward end of the sail locker. Dunno if install was part of the earliest engine (Atom4 or Weserbeake?), but the Yanmar installer did leave it in place.  I believe that the vented loop is there to prevent seawater from siphoning to the engine when it is not running. There is no question that a good bit of the engine is below the water line when the boat heals.  I don't want to have to shut off the through hull every time I shut off the engine. 
>>     The brass vent device present at purchase dripped.  The drip ran down the line and onto the starter, which it ruined. I replaced the starter, and the brass vent with a Marelon vent. 
>>     These old boats are enjoyable for me. I really do love worrying about all of this stuff, but I don't want it to get too much more expensive. My wife once said that I might enjoy an even older boat even more.  I replied "how about two old boats."
>> 
>> What do you think about the siphoning concern? What do others think?
>> 
>> Regards, Don 
>> 
>> On 11/4/11 10:29 PM, S Orton wrote:
>>> 
>>> Don,  Your email indicates you have a "vented loop" for your engine sea water cooling?  To me that doesn't sound like a good practice, as you could loose your cooling to your engine with a vacuum breaker on the suction side of a pump.  The scenario- marine growth partially plugs the intake, negative pressure increases on the pump suction, the vacuum breaker opens, and lets air into the pump suction loosing sea water flow.  I would definitely check into this.
>>> Cheers, Steve O  
>>>  
>>> Date: Tue, 1 Nov 2011 08:44:23 -0600
>>> From: maxsoto at gmail.com
>>> To: listserve at catalina38.org
>>> Subject: Re: [C38] Vented loop for head discharge
>>> 
>>> Steve,  Since the loop+vent breaks the siphon, the "pressure" on the joker valve is from the grey water located between the head and the loop.
>>> Don, same thing happened to the PO, so he made a box that raises the head about 7 inches, and added a vented loop to the intake hose.  Apparently he found he boat with 1' of water. I think that the vented loop for the intake  is enough, so I'm going to remove the riser box. Short people have their feet on the air while seating in the head! 
>>> 
>>> Regards,
>>> 
>>> Max
>>> 
>>> 2011/11/1 Don Strong <drstrong at ucdavis.edu>
>>> Steve: I did the vented loop head-to sea retrofit because my insurer demanded it.  Big job! The exit hose goes up the along the hull, through the sink top and reaches an apex are just under the deck. The vent is at the apex. The loop+vent breaks the siphon. I don't see how the grey water problem is any different between "overboard" and "waste tank." When the valve is thrown to tank, grey water sits behind the joker valve just as it does when the valve is thrown to overboard. 
>>> 
>>> I also installed a vented loop for the sea water intake for the head after we awoke with 6" of water in the boat (someone "moi?" was too sleepy to flip the switch to "dry bowl during the night).  There is also a vented loop on the sea water intake for engine cooling. I recently replaced the vent.
>>> Don
>>> 
>>> 
>>> On 10/31/11 11:43 PM, Steve Smolinske wrote:
>>> Question for anyone with a vented loop in their head discharge.   Looking at it on paper it seems that the pressure of the grey water in the section from the head to the vented loop would be enough to leak back into the toilet bowl.  I know there is a duckbill valve and a flapper valve in the head to stop the reverse flow, but as we all know if you leave the discharge seacock open the head will fill up.   Does the vented loop work because the head pressure of the grey water in the run from head to loop is not as great as that coming from the seacock?  Any experiences are greatly appreciated.   Thanks
>>>  
>>> Steve
>>> 
>>> 
>>> _______________________________________________
>>> Listserve mailing list
>>> Listserve at catalina38.org
>>> http://catalina38.org/mailman/listinfo/listserve_catalina38.org
>>> 
>>> -- 
>>> Donald R. Strong
>>> Professor
>>> Dept. of Evolution and Ecology
>>> University of California, Davis 95616
>>> 
>>> _______________________________________________
>>> Listserve mailing list
>>> Listserve at catalina38.org
>>> http://catalina38.org/mailman/listinfo/listserve_catalina38.org
>>> 
>>> 
>>> 
>>> 
>>> -- 
>>> Max Soto
>>> C38 #198 ESTANCIA
>>> Puntarenas, Costa Rica
>>> 
>>> _______________________________________________ Listserve mailing list Listserve at catalina38.org http://catalina38.org/mailman/listinfo/listserve_catalina38.org
>>> 
>>> 
>>> _______________________________________________
>>> Listserve mailing list
>>> Listserve at catalina38.org
>>> http://catalina38.org/mailman/listinfo/listserve_catalina38.org
>> 
>> -- 
>> Donald R. Strong
>> Professor
>> Dept. of Evolution and Ecology
>> University of California, Davis 95616
>> _______________________________________________
>> Listserve mailing list
>> Listserve at catalina38.org
>> http://catalina38.org/mailman/listinfo/listserve_catalina38.org
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://catalina38.org/pipermail/listserve_catalina38.org/attachments/20111106/e59ff1f3/attachment-0001.htm>