Advice on cutting a hole here?

J

JosefR

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Sep 18, 2016
127
Catalina 30 Gulfport, Mississippi
http://forums.sailboatowners.com/index.php?threads/holding-tank-vent-clogged.181515/#post-1326136

In the above thread, I decided to drill a hole in my 89 Catalina 30TR for venting the holding tank as it is clogged somewhere. I AM LOOKING FOR THE C30 OWNERS WHO HAVE DONE THIS ALREADY.

Anyone with specific knowledge on how I cut this hole, or if it is OK to cut a hole in this location?
http://i43.photobucket.com/albums/e375/madwand1/20160909_102114_zpsqdqwpp1m.jpg
I would like to place the thru Hull fitting in the top right corner of this cabinet.
 
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JohnVTX

JohnVTX

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Jul 14, 2015
840
Catalina 30 Stillhouse Hollow Marina
I would not create a new hole. Fix the clog. It vents up through the lifeline stanchion just above the toilet. Can't take much to clear it.
 
J

JosefR

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Sep 18, 2016
127
Catalina 30 Gulfport, Mississippi
Thanks, but I asked about adding a vent, not tearing my boat apart to get to a microscopic hole and a tube I can't access. I explained this.
 
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KD3PC

KD3PC

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Sep 25, 2008
1,069
boatless rainbow Callao, VA
usually the vent holes are nearer to the water line...as the vent will "vent" pretty stinky stuff and the closer to the toe rail the more apparent that vent process will be to those aboard. You are wanting to minimize the rising odor...being beyond the hour glass of the hull, should allow the odor to sink, as opposed to being in the windstream to the topside.

Other than that...small hole saw, nothing in the way and some epoxy to seal the cut and a new fitting, with appropriate hose/vent line should do the deed.

Your boat,
 
Doug4bass

Doug4bass

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Jun 9, 2004
615
Catalina 385 Marquette. Mi
Peggy recommends a clam shell thru hull....which my 385 has. Not a fan of the stantion vent. Call Catalina and ask about your proposed hole location. They're customer service is second to none. I reiterate. ..second to none.
 
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Peggie Hall HeadMistress

Peggie Hall HeadMistress

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Dec 2, 1997
8,729
- - LIttle Rock
KD3PC said:
usually the vent holes are nearer to the water line...as the vent will "vent" pretty stinky stuff and the closer to the toe rail the more apparent that vent process will be to those aboard. You are wanting to minimize the rising odor...being beyond the hour glass of the hull, should allow the odor to sink, as opposed to being in the windstream to the topside.
Click to expand
If you put a vent thru-hull near the waterline on sailboat, it will be underwater when the boat heels, forcing water into the tank that can overflow into the toilet discharge line and overflow the toilet. As for your theory of holding tank odor... it's created by anaerobic conditions in the tank...anaerobic gasses are heavier than air...they don't rise.

There have been many discussions on sbo.com about holding tank odor and how to ELIMINATE it by preventing it (yes, odor out the vent CAN be prevented!)...you might want to spend some time searching the archives for them 'cuz although you've been a member for eight years, it doesn't appear from your posts that you've ever read any of them! Best place to start is with the Plumbing and Sanitation forum and the Ask All Sailors forum.

Several weeks ago a Catalina owner posted how he installed a vent thru-hull and relocated his holding tank vent line from the stanchion to it. He included photos...but I haven't been able to find the thread and I can't remember who it was. So if you're out there, please show yourself and help Josef get it right!
 
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druid

druid

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Apr 22, 2009
837
Ontario 32 Pender Harbour
I'm with Peggy on this one! In fact, as long as you're messing around with vents, put TWO in, one on either side of the bow. 1" minumum hose. You'll be amazed at the difference.

druid
 
JohnVTX

JohnVTX

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Jul 14, 2015
840
Catalina 30 Stillhouse Hollow Marina
JohnVTX said:
I would not create a new hole. Fix the clog. It vents up through the lifeline stanchion just above the toilet. Can't take much to clear it.
Click to expand
Dumb idea. That is a reply to your topic header. But it is your boat.
 
J

JosefR

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Sep 18, 2016
127
Catalina 30 Gulfport, Mississippi
You might have some credibility if you were to explain why it's a dumb idea, but when someone who knows what they're talking about on the subject has already given her opinion on it and been backed up by many people, it just makes you look ill informed.
 
JohnVTX

JohnVTX

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Jul 14, 2015
840
Catalina 30 Stillhouse Hollow Marina
JosefR said:
You might have some credibility if you were to explain why it's a dumb idea, but when someone who knows what they're talking about on the subject has already given her opinion on it and been backed up by many people, it just makes you look ill informed.
Click to expand
Because you will take on water if you sail at all in heavy air. I'm not worried about your opinions of me. You asked for opinions of your idea and I gave mine. Opinions are just that. Don't want them, don't ask for them.
 
J

JosefR

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Sep 18, 2016
127
Catalina 30 Gulfport, Mississippi
Actually, I did not ask for opinions. It'd be really helpful, in the future, if you'd take the time to read posts that you reply to. Thanks anyway.
 
JohnVTX

JohnVTX

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Jul 14, 2015
840
Catalina 30 Stillhouse Hollow Marina
Oh I get it now. Yeah, great idea.you are right, go for it. I only wish I had thought of it first. I may try it myself.
 
Bob S

Bob S

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Sep 27, 2007
1,774
Beneteau 393 New Bedford, MA
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I used a hole saw. I did this a few years ago. I used the bolts holding the deck to the hull and a chainplate as a location guide. Measured 10 times :) and cut the hole to fit the fitting. I used 1" hose and a Uniseal per Peggie's instructions. I went almost straight up which isn't the best scenario but It has worked well. We almost never have issues with smells anymore.I put the hole exactly where you reference. I didn't use a clam shell as I would really have to bury the rail which I try avoiding at all costs.
 

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J

JosefR

.
Sep 18, 2016
127
Catalina 30 Gulfport, Mississippi
Thanks Bob! Pretty straightforward, just drill a hole...

Peggie Hall HeadMistress said:
(use an open "bulkhead" thru-hull fitting, NOT a "vent" thru-hull)
Click to expand
The guy I talked to at Catalina was adamant to use a vent thru hull and Peggie says adamantly not to. I really don't see the difference, other than cosmetic. Neither will prevent water from entering, so why does Catalina insist on this? I couldn't get a satisfactory answer from the guy...
 
Justin_NSA

Justin_NSA

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Jul 7, 2004
8,402
Hunter 30T Cheney, KS
I could see a clam shell over the fuel tank vent to help keep water out of the fuel ( have an inline dryer), or on the fresh water vent to keep soapy or other dirty water out. But I don't guess I see how it is preferred over a thru hull for the holding tank. What are you trying to keep out? To me it's in the same category as the bilge or shower discharge holes. Just my $.02. I'm open to a good explanation.
 
J

JosefR

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Sep 18, 2016
127
Catalina 30 Gulfport, Mississippi
I don't see how a clamshell is gonna keep anything out anyway. If there is no valve, it's the same as wide open. Seems like just added expense for nothing.
 
J

JosefR

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Sep 18, 2016
127
Catalina 30 Gulfport, Mississippi
Okay, I just got off the phone with Jerry Douglas, an engineer for Catalina in Florida. He says that I am going to be cutting through the hull liner as well as fiberglass, and that means there will be an air space in the hole that I cut. This means that possibly water could get inside so I need to be sure that either my fitting is sealed well or that I fill the inside of the hole.

As far as the clamshell, he said that is what they recommend, but he couldn't explain why it's any better than an open fitting. He said it wouldn't matter.

So I will be buying my fitting and my hose from West Marine in Biloxi. Is there a recommended marine sealing material that I can get while I'm there?
 
Parsons

Parsons

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Jul 12, 2011
1,165
Leopard 40 Jupiter, Florida
To clarify Bob, you drilled from the outside in, so that fraying at the end of your hole is inside the boat. Right?
 
Parsons

Parsons

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Jul 12, 2011
1,165
Leopard 40 Jupiter, Florida
It also looks like you sealed yours with butyl tape, following Mainesail's advice.
 
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