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Hi everyone. We are at our wits end with a holding tank problem.
Our CD Intrepid 40 is a wonderful boat. We have had her for a couple of years now. The holding tank has 2 inlets, for fore and aft heads. The tank can be emptied (obviously, offshore) via a macerator pump connected to a 1 inch valve located aft. The valve is original CD issue, so I believe this system was installed when the boat was built. This system always worked well and was useful since there is only one pumpout station in our area and it is quite far. But one day it stopped working. To make a long (and messy) story short, we have replaced the pump and all hoses leading to the valve to no avail. It gets worse. We finally went to the pump out station and their pump could not get anything out.
So now we are suspecting that sediment has blocked the pickups for both the macerator pump and the waste outlet in the deck. Since very few of these boats were built we have been unable to get any schematics or useful information of how this system is configured so we can get to the root of this problem. And, even if our suspicion is correct we would really appreciate any and all suggestions and ideas to help us out. Thanks.
Thank you very much for your response. Haven't thought about it because air does come out whenever the head is used. Does it follow that air does get in? Maybe. I will check it anyway. Is there anything I should be looking for?
i would venture a guess that the solids have settled in the tank and blocked the outlets. i have heard of people sticking a rod into the inspection port and agitating the solids to loosen things up. this is especially a problem with gravity fed hold tank drains. when toilets are blocked i have heard of plumbers using dish detergent to dissolve blockages. all i can say is good luck.
vmelendezlugo wrote:Thank you very much for your response. Haven't thought about it because air does come out whenever the head is used. Does it follow that air does get in? Maybe. I will check it anyway. Is there anything I should be looking for?
The exterior vent fitting is often screened to prevent spiders/wasps etc. from gaining access and plugging the vent. Over zealous hull waxing buildup over the years is another common culprit. The interior line leading to the vent may also have become blocked. The vent must remain open to facilitate both filling and emptying the tank.
Perhaps a pressurized back-flush of the system from the pump-out fitting might loosen any blockage?
But only if there's room in the tank for extra fluids!
I recently opened up the floor on my CD36 to change the fuel tank. There was a PVC pipe there that ran from the head to the holding tank. When I removed it it was filled with solids which were probably precipitates of salts. It wouldn't be a stretch to imagine this clogging to the point where nothing could get through. My only thought of a solution would be flushing with vinegar and hope it would dissolve some of the salts. Good luck
I'm with Jim Walsh on the vent issue.
I started getting some foul odors from my holding tank and checked the vent, which I replaced. I also replaced the badly corroded aluminum vent on my transom with a bronze one from Spartan. It was a great improvement.
--Joe
Former Commodore, CDSOA
Former Captain, Northeast Fleet
S/V Crème Brûlée, CD 25D, Hull # 80
"What a greate matter it is to saile a shyppe or goe to sea."
--Capt. John Smith, 1627
Really grateful to everyone for your insights. Here is what I have seen so far. Checked the vent and the line and they are clear, which makes more probable that something is blocking the outlets. What really puzzles me is that they are both blocked, it seems. I don't know when it was the last time that tank wsa cleaned up, and being salt water fed, go figure. Solids are very probable. I have read about vinegar, baking soda (and both). Also about some products like Calgon. I'm wondering what would be best to use, so that I can go through the gruesome ritual of emptying the tank through a hose in the inspection port only once!
Again, thank you all for your interest. I'll let you know how the saga ends.
This post reminded me to check on my vent for the holding tank as I remembered from the end of last year that there was a slight vacuum after discharging (3 miles out of course). Sure enough the vent was now completely clogged after sitting over the winter. The hose from the holding tank to the vent was clear but the vent itself was clogged. I took it off the hull and reamed it from both side to clear the crud. Bedded with butyl rubber and now it is venting freely.
vmelendezlugo wrote:... and being salt water fed, go figure. Solids are very probable.
This is why we do not use raw water to flush with, just fresh water from the sink. It also keeps odors down!
-michael & Toni CDSOA #789
s/v KAYLA CD28 #318
2012 FLSTC Heritage Classic
Niceville FL +30° 30' 24.60", -86° 26' 32.10"
"Just because it worked, doesn't mean it works." -me
No shirt + No shorts = No problem!
We are happy to report that our holding tank problem has been solved. After checking all hoses and ,yes, the vent and finding them all clear we had to accept the harsh reality that the tank pickup was plugged. After emptying the tank we could see a lot of sludge (I am being kind!!) resting in the bottom. We used a RV Swivel stick (Amazon, $17.89) and it did a really good job of dislodging both the sludge and some pretty big salt deposits. A swivel stick is a 3 foot PVC pipe with a hose attachment in one end and a bronze swivel with two holes in the other. Water pressure makes it spin and it gives a very powerful rinse without the possibly excessive force of a pressure washer. They are widely used by RV owners to clean their holding tanks.
After that the pump started working, albeit a little sluggish. After cleaning the whole tank we emptied the wash water and poured some baking soda and 4 gallons of really cheap white vinegar that we bought at a local warehouse. We let it fizz a while, then filled the tank half way and let it stand a few hours. Then we filled it up and let it stand some hours more. Then we started the pump again and it has never worked better! Totally clear. Fresh water in the system and frequent maintenance from now on.
Again, we thank you all for your sympathy and your great advice. Fair winds,
V. Melendez-Lugo
S\V Circe
CD Intrepid 40
Fajardo, Puerto Rico
glad you solved your blockage problem. on a hindsight note: there are products that supposedly dissolve solid deposits (including paper) with bacteria and enzymes. One is named RV Digest-It Holding Tank Treatment. It also helps with odors they say. Worth a try for sure.
