Holding Tank Work

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mike37909's picture
mike37909
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Posts: 161
Holding Tank Work

My boat smelled like sewage so I cut all the sanitary hoses and pulled the holding tank. I had pumped and flushed it 3 times but it was full of scale. Hosing it out and sloshing it around got prob 30 lbs of scale out of it. I assume it is from calcium in seawater reacting with urine? Anyway my tank can be lifted with one finger in the inlet now.
Put it back in and replumbed with PVC pipe and flexible hose couplers. I threw out all the old hose and fittings because they reeked and I didn't want to fool with them. Problem was that there were 4 different sizes of plumbing and I didn't know it. The toilet was 1" the tank inlet 1-1/4" tank outlet 1-1/2" and the pump out fitting was 2". Unfortunately I didn't notice this and assumed it was all 1-1/2". Too many trips to lowes. What a pain in the butt.
I also cleaned and painted the bilge area before putting the tank and new plumbing in.
The manufacturer or previous owner had slid hose over threaded fittings to make them fit and put a hose clamp on. Not sure how well that works but judging from the smell it didn't. Just have 1 leak to fix.
Boat smells great even when you lift the bilge access now.

Catalina 36 MK1
1984 Hull #306

 

deising's picture
deising
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Joined: 11/3/08
Posts: 1351

Well, that was a nasty job, to be sure, but sounds like you can enjoy your boat a lot more now. Good job!

Duane Ising - Past Commodore (2011-2012)
s/v Diva Di
1999 Catalina 36 Hull #1777
Std rig; wing keel, M35B, Delta (45#)
Punta Gorda, FL
http://www.sailblogs.com/member/diva-di/

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baysailor2000
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Posts: 218

And to keep the smell out I use fresh water to flush.

Haro Bayandorian, 1999 C36 MKII, Sail La Vie #1787, M35B,
Coyote Point, San Mateo, CA.

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Steve Frost
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Posts: 788

I second the fresh water flush thought for reducing head odors.

As for your repair I appluad you, this is an item that can greatly effect the marketability of your boat along with making it far more comfortable to be aboard. When I was shopping for my boat I went aboard several C36's one may have been a very nice boat but, the head odor hit me as soon as I put my head in the companionway. I pulled my head out and never looked back.

Cepheus dream
C36 MK I # 825
MK I Tech Editor No Mas

Waxing Moon's picture
Waxing Moon
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Posts: 21

I like the idea of switching to the PVC pipe.  PVC pipe is not permeable and would never exude smell.  It is very durable and last for a very long time if not left to the effects of direct sunlight.  I've heard of one other guy who did it and he is happy with result.  However, no description of how the actual replacement was managed.  I wonder how difficult it would be on top of the already painful job of replacing  the flex hoses would be.

Captain Moon
Waxing Moon
2002 C36 MK II #2105
Port Charlotte, FL

pkeyser's picture
pkeyser
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Joined: 5/18/13
Posts: 659

Great information! If you can share any tips learned about converting to PVC, we would find it interesting. I was hesitant about trying to do this until reading your posting. We too have a beautiful boat with head odors and my number 1 project this layup season will be to conver to PVC and remove/clean the tank.

Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B

dpower
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Joined: 6/20/08
Posts: 231
Use fresh water to flush and eliminate odors. We lived aboard for nine years and quickly learned to use fresh water from the head sink fixture. Now, after having our '98 for 15 years, no odors and we still have the original hoses.

David S. Power
Two If By Sea #1687
Burnt Store Marina
Punta Gorda, FL

knotdoneyet
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Joined: 7/27/12
Posts: 253

I could see using PVC for the run betwees:
- Deck Pumpout and Holding Tank
- Head and Holding Tank
- I guess vent but mine doesn't stink

The challenge with the smell is that the hoses become permeated.  Your new flexible hoses, used to connect the PVC, run between the holding tank, macerator and thru-hull, will also become permeated and smell over time.  The cheap hose will stink faster and the more expensive takes more time to permeate.

I spent some bucks on the really good hose reivewed on Practical Sailor between the head/deck pumpout and holding tank and so far, so good (Trident Sani Shield).  They didn't sell it in the smaller sizes so I have the next best (Sealand I believe) going from the tank to the macerator and thru-hull.  Looks like they may now.

Tip on the white hose, make sure to heat it and you will use no profanity!!!

I still have the original Sealand vent hose, it's doesn't smell.
 

2000 C36 MKII 1825

Waxing Moon's picture
Waxing Moon
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Posts: 21

I have a 2002 36 MK II.  The big problem with sea water flush is the unbelievable stink that comes with the first flush after a short time of nonuse (one week).  It is so bad that breathing the fumes can exacerbate any lung condition.  Then flushing that into the holding tank requires way too much volume, shortening the use of the tank before emptying is necessary.  (My tank is only 14 gallons!)  As it turns out, my boat 's sea water intake for the head is the same one that drains the head sink.  I rarely use the head sink.  If you close that seacock, you can make a freshwater flush by partially filling the sink, then flush.  Really, it is the first flush that is the issue. Therefore, the last flush should definitely be fresh water. With that solved, time to change the hoses.

Captain Moon
Waxing Moon
2002 C36 MK II #2105
Port Charlotte, FL

Waxing Moon's picture
Waxing Moon
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By Neptune, I'm going to give the PVC schedule 40 conversion a try!  Results will be posted. I'll try to with hold the ensuing profanity.

Captain Moon
Waxing Moon
2002 C36 MK II #2105
Port Charlotte, FL

VermontSailor's picture
VermontSailor
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Joined: 11/15/08
Posts: 100

I like the idea of using PVC pipe, but how do you make the connection to 1-1/2” OD deck fill pipe with schedule 40 PVC pipe ? 1-1/4 schedule 40 PVC actual OD is 1.660 inches.

Nile Schneider
Mañana C36 #1798
Lake Champlain, VT

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