Replacing holding tank?

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Chris Martinson

Does anyone have any advice regarding replacing the holding tank (MKI) and I'm sure there are opinions on fixing the poor venting?  Thanks

Chris Martinson
More Therapy
Hull no 945
Chris Martinson
More Therapy
1989 Hull # 945

Mike Vaccaro

Chris,

What's wrong with your tank and/or vent?

Cheers,

Mike
1988 C34 Hull #563
Std Rig / Wing Keel

Stu Jackson

#2
Chris, my experience (and reading) indicate that holding tanks are usually the LAST problem in waste holding systems.  Rarely do the tanks permeate, but rather the hoses need to be replaced.  This comes from nine years of reading this and other websites about boats and plumbing systems.  I only recall one person here discussing having to and maybe actually replacing a holding tank, given the difficulty of removal which required removing all the hosing and the macerator pump.  You could do a search on that phrase, and maybe find it.  Also, Peggie Hall, who's written an entire book on this subject of odors, notes that the tanks usually are OK.  If they do go, it's because of a seam failure.  Ronco tanks are given high grades.

The venting, OTOH, is a real pain in the neck on our boats, due to two major things:  the vent line size and routing is too small and too tortuous, and the small hole in the stanchion makes the situation worse.  I also do not recall anyone posting on this board or our C34 website HOW they fixed it.  Someone may have written about running the new vent line into the anchor locker.  Not a bad idea, don't remember if it was here or another 'site.

Peggie's recommendations are clear:  don't' use a filter, it only makes things worse, make it bigger (1 inch), use a real through hull not a stanchion, don't use a screen on it, and if I remember, slope the new vent line up at 45 degrees.  As many have mentioned, this makes it damn near impossible to do on ANY boat, but the recommendations are based on the chemical compositions of the waste and the amount of air circulation needed to prevent odors.  I have been thinking about how to do it on our boat and haven't come up with an easy fix other than simply biting the bullet and drilling a hole in the port side of the hull just to port of the holing tank as far up high and putting the thru hull for the new vent right there.  I haven't wanted to deal with the larger hole required in the holding tank.
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

Stu Jackson

Chris, PS to my last reply.

One other source of odor that Peggie mentions is bilge water.  She notes that even after tank and hose replacement, many people continue to mention odors and that most have been traced to bilge water.

I don't know if you have the magical clean as a spider web bilge, but it is a recurring theme from Peggie, based on real life stories.

You may also want to check if there is any "dirty" water UNDER your tank.  Never know if you've been heeled enough on starboard tack to slop water underneath the holding tank.
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

Jeff Kaplan

chris, when i bought #219 in sept. of '04, one of my first major projects was to replace the entire sanitation system, everything. the boat stunk, including the tank, which btw, is stock right from catalina,  same one used today. i did increase the vent size to 3/4". as mentioned, the hoses really let off an odor, so definately change those, the fittings, vented loops, and y valves. i even relpaced the head. after doing this, and a very through cleaning and airing out, no more smell. do what you have to to get the job done. nothing worse than the smell of the system in your boat...jeff
#219, 1986 tall rig/shallow draft. "sedona sunset" atlantic-salem,ma

John Langford

I have been considering providing  a little cross ventilation in the holding tank compartment by cutting in two 3" vents: one at the aft end of the compartment under the nav table and the other forward midway along the settee. I have replaced all the hoses and used PVC piping where I can so I don't have a smell problem. But I still think a little air movement around the tank can't hurt. Anybody else done this or have views on its usefulness?
Cheers
John
"Surprise"
Ranger Tug, 29S

Roc

John,
I added an extra vent in the holding tank, for better aerobic airation.  I drilled a hole in the inspection cap and fitted a 90 degree elbow with a hose barb on one end, and a thread with nut on the other.  I used 5200 to seal off the threaded part of the elbow onto the inspection port.  Although caulking plastic isn't really optimum, it's been like this for about 6 years with no issue.  I ran the hose, keeping an upward slope, into the port side storage areas behind the settee seat backs, forward into the v-berth port-side locker, then out the side of the boat with a fitting about a few inches below the rub rail.  The tank now has two vents, this new one, and the original one that leads to the stanchion base.
Roc - "Sea Life" 2000 MKII #1477.  Annapolis, MD

Stu Jackson

John, as I understand it you're considering venting the holding tank area esinto the saloon.  I've thought about it and it seems to be a situation where if you ever did have odors inside the holding tank area all you'd be doing is letting those smells come into the saloon, instead of containing them inside.  I don't think it's a good idea.
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

Jeff Kaplan

john, i agree with stu,keep the smells, if any contained to that area and don't let them loose in the cabin. i took care of a situation like that, posted above. if the hoses and tank are permeated and giving off odors, replace them all...jeff
#219, 1986 tall rig/shallow draft. "sedona sunset" atlantic-salem,ma

Roc

Would like to add that I've been using Odorloss, with good success.  The added vent allows oxygen to keep the aerobic bacteria alive (i.e. no smell).  That's the key to the sanitation system, keep the oxygen flow.  Like I said above, my extra vent line exits the boat on the port side, behind the v-berth storage locker on that side.
Roc - "Sea Life" 2000 MKII #1477.  Annapolis, MD

Stu Jackson

Roc, that's a great idea.  I understand the routing of the second, forward vent.  With a Mark I boat there would exposed hose in the V berth between the top drawer and shelf, because the Mark IIs have a higher cabinet there.  Did you use a standard open thru hull fitting as Peggie recommends?
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

Tom Lanzilli

I intend to run a second vent line from my holding tank, however, I am thinking of running it forward to the anchor well.  Any thoughts?
Tom Lanzilli
Ithaka, 2004, #1660
Guilford, CT

Ken Juul

Roc, 
How about pictures and a write up in Projects.  A list of parts would be good also.  This is something that we all should probably do.
Ken & Vicki Juul
Luna Loca #1090
Chesapeake Bay
Past Commodore C34IA

Stu Jackson

Tom, some have suggested that, but the lack of air movement inside the well would most likely preclude any air getting into the vent.  I'd try asking Peggie at www.catalinaowners.com on the Head Mistress Forum.
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

tonywright

On the MKII the vent for the forward water tank is in the anchor locker. I am not sure I would want the holding tank vent right next to it. Plus, smells tend to ride with the wind, as we have discovered if we sit in the cockpit when the current vent is in action! Placing the vent further aft would seem more palatable? If you are going to run a line that far, what about the stern? There is already a vent there for the diesel tank. Shouldn't be too tough to pull a pipe through there?
Tony Wright
#1657 2003 34 MKII  "Vagabond"
Nepean Sailing Club, Ottawa, Canada