[C320-list] Head Vent

[Ted Harrison]

Amazing Scott. Thanks for sharing the fuel vent as well. I have this
problem as well. I just purchased hull 424.

Holding tank was wife's first priority!!!!! It was cracked! What a nasty job!

Ted

Sent from my iPhone

On Jul 24, 2013, at 7:52 PM, Scott Thompson <surprise at thompson87.com> wrote:

> You are missing two things:  First, inadequate ventilation leads to much worse smell by encouraging anaerobic bacteria to thrive. Second, when you pump, out, you risk cracking your holding tank if the ventilation is inadequate because of the high suction applied. It is the significant negative pressure from pumpout that you need to worry about, not the small pressure generated by flushing the head. So you definitely want a good amount of cross sectional area for the vent.
>
> My last boat had a through-the-stanchion vent on the fuel tank. There was a hose from the tank to the base of a stanchion. There was a separate hole in the stanchion about 4 inches off the deck, maybe 1/4 inch in diameter.  I had problems when I bought that boat with poor fuel venting causing overflow when I filled the tank. When I investigated, I discovered that the base of the stanchion had never been drilled out to permit air to pass from the tank to the stanchion. Rather than correct that, I ended up installing a separate fuel vent on the transom.
>
> On 7/24/2013 3:17 PM, Graeme Clark wrote:
>> Apologies if I am hijacking this thread but I am curious as to the position of the head vent as in the manual for my hull (#303, 1996), it shows the vent pipe going to a stanchion that supports the guard wires and the implication is that the stanchion is hollow and the air flow exits and enters through the hole that the guard wire passes through. Obviously with the wire running through it there is only a small annular area for the air to pass it so the flow will not be great -  but then it doesn't really have to be great as the holding tank is plastic and will thus take some small expansion temporarily (acting as a gas accumulator really!) and then the excess pressure can disperse over time through the stanchion?
>>
>> Am I missing something here?
>>
>> Graeme
>>
>>
>>
>>
>>
>> Message: 7
>> Date: Wed, 24 Jul 2013 13:43:05 -0400
>> From: Ted Harrison <tharrison at innovations-plus.com>
>> To: "C320-List at Catalina320.com" <C320-List at catalina320.com>
>> Subject: Re: [C320-list] Head Vent
>> Message-ID: <-8749710888664970442 at unknownmsgid>
>> Content-Type: text/plain; charset=ISO-8859-1
>>
>> I bet the vent has been replaced. With a one piece unit. The out side
>> cap is part of the unit!  I think you should be able to feel the air
>> flow.
>>
>> I just replaced all hoses, holding tank and head. Give me a call if you like.
>> 857-756-7587
>>
>> Ted
>