[C38] Vented loop. sea water cooling intake
Don Strong
drstrong at ucdavis.edu
Sun Nov 6 18:20:05 EST 2011
Max: Hey, that is a great find. Good sluthing! Regards, Don
On 11/6/11 3:17 PM, Max Soto wrote:
> Don,
> According to the Catalina drawings, That is the original vent location
> for the C38.
> This vent is supposed to avoid flooding of the muffler and ther
>
> Sent from my iPod
>
> On Nov 5, 2011, at 8:17, Don Strong <drstrong at ucdavis.edu
> <mailto: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 <mailto:maxsoto at gmail.com>
>>> To: listserve at catalina38.org <mailto: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
>>> <mailto: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
>>>
>>>
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>>>
>>> --
>>> Donald R. Strong
>>> Professor
>>> Dept. of Evolution and Ecology
>>> University of California, Davis 95616
>>>
>>>
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>>>
>>>
>>>
>>> --
>>> Max Soto
>>> C38 #198 ESTANCIA
>>> Puntarenas, Costa Rica
>>>
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>>
>> --
>> Donald R. Strong
>> Professor
>> Dept. of Evolution and Ecology
>> University of California, Davis 95616
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>
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--
Donald R. Strong
Professor
Dept. of Evolution and Ecology
University of California, Davis 95616
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