holding tank fitting

[Bobg]

Hi All, does any one know where I can find a certain holding tank fitting?   Roc posted it last summer, however I have exhausted my knowledge of the internet to find one like it.  I am going to try post a picture of it here by clicking on additional options below and attach it.  Thank you  Bob

[Ron Hill]

Bob : There are two parts to the fitting in your picture:
1  The threaded portion into the tank itself
2. The 1/2"(?) elbow into the threaded tank piece

Which one are you looking for? 

[Bobg]

sorry Ron, looking for the bigger white fitting which attaches to the holding tank.

[Bobg]

I wasn't concise in my last post, what I am looking for is a larger fitting to install on the top of my holding tank that I can install a 90 degree barb fitting in to run another vent line. this could also do double duty as a inspection port.  On my 88, I  have one portal on top of the holding tank, that is where my OEM vent fitting is.  I would like to put another vent in for cross ventilation as per Peggy Halls book. Thank you, appreciate any help  Bob

[Roc]

My 2000 model holding tank came with an inspection port.  I installed the elbow into the cover of the existing inspection port.  I had to buy two elbow fittings because I wanted two threaded nuts to attach the elbow into the cover (the elbows only come with one). One would be on top and the other threaded from the bottom.  This essentially 'sandwiched' the cover between them.  I used 3M5200 to caulk.  I've had this set up for 10 years with no issues of leakage.

[Ron Hill]

Bob : I've never seen a fitting like the white one on your tank.  Is it a 4" threaded fitting that is going into the holding tank?
If it is a 4" threaded fitting, it might be a standard 4" male clean out thread, but I'm not to sure where you'll find a female fitting to install in the tank itself. 
Even if you find one it's going to have to be "hot air" welded in the tank itself. 
Good Luck with your cross ventilation project ! 

[C Martinson]

I can't comment on where to find the fitting you are looking for but have this comment.  When I was thinking about doing the same thing to my old tank; several people - including the OEM tank manufacturer, strongly recommended against it.  Their reasoning was that while it isn't obvious, at every fitting the tank is reinforced and adding a fitting stresses the tank which could lead to cracking etc.  I can't tell what year your boat is....in the end I replaced my tank without too much trouble.  It was last year and Catalina still had production tanks in stock.  In the end - venting wasn't my issue - the tank itself became permeated with the smell.......all fine now with the new tank.

Chris
More Therapy
1989 HN 945