Catalina 355 holding tank blocked at thru hall

Nov 8, 2020
6
catalina 355 Sidney bc
Wondering if any one has had a problem with draining their holding tank. This is a passive drain system. Ours is blocked.
 
Jan 1, 2006
7,040
Slickcraft 26 Sailfish
That's sounds like a problem. But hopefully this post will bring your up to the top again.
 
Dec 2, 1997
8,709
- - LIttle Rock
I'm guessing that by "passive drain system" you have a gravity drain tank. If the thru-hull stays closed, sludge can build up in the drain line, clogging it. Are you able to pump out?

--Peggie
 
Feb 26, 2004
22,760
Catalina 34 224 Maple Bay, BC, Canada
Stu
I have searched the 355 site to see if here is a resolve for this issue.
Mike, the deficiencies of a Google Group is that it IS hard to search, compared to a "website." I've found that with that group of very helpful skippers, you would get a good response if you joined the group and asked the question there, too. Good luck. I don't have a C355 Manual, so I can't help you there. I do know friends with the same gravity system if that's what you have and what Peggie has noted. If so, she may well be on the right track. If you do run into a C355 manual, please let me know, and I can post it on our C34 Tech wiki. FYI, in case you didn't know, we're the C34 & C355 International Association, but they did their own Google group instead of joining on our C34 website back when they started out about a decade ago. Great boats, same layout as ours with many improvements (as you know! :yikes:).:):):)
 
Dec 2, 1997
8,709
- - LIttle Rock
I'm 99% certain I've identified the problem...I'm still working on finding the cure for a totally impacted overboard discharge hose. The best I've come up with so far is to send a diver down to start breaking up the sludge and digging it out of the thru-hull with a long blade screw driver. Surely there's a better way.. so I'll keep looking.

--Peggie
 
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May 7, 2012
1,338
Hunter e33 Maple Bay, BC
+1
Mike, this will be either a mechanical fix or chemical fix. Peggie has addressed the mechanical option. Possibly Peggie could also comment on maybe using a dose or double dose of Noflex Digestor. I have a gravity drain holding tank on my Hunter and after 9 sailing seasons with lots of miles under the keel, I have had no issues. Also I don’t believe that this is unique to our system.
 
Nov 8, 2020
6
catalina 355 Sidney bc
I'm guessing that by "passive drain system" you have a gravity drain tank. If the thru-hull stays closed, sludge can build up in the drain line, clogging it. Are you able to pump out?

--Peggie
Yes, we pumped out yesterday. I even opened The thru-hull hoping it may free the clog, but no luck.
 
Dec 2, 1997
8,709
- - LIttle Rock
I think it'll take something stronger than NoFlex, but I have a call into 'em to ask and also a couple of other products.

And while I have the floor...is there any chance that someone flushed something they shouldn't have that's blocked the hose...that it may not be just a sludge buildup?

--Peggie
 
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Nov 8, 2020
6
catalina 355 Sidney bc
Just the two of us have been the boat, so it wouldn’t besomething that got flushed.The boat has sat for six months, as we couldn’t get across the boarder due to COVID. I was told the previous owner had to get a diver to blow air up from the thru-hull to clear the blockage before. That’s why I’m thinking this is a common problem. I hope I’m wrong.
 

leo310

.
Dec 15, 2006
635
Catalina 310 44 Campbell River BC
If the PO had this problem you will need to do the same to fix it. I would add an isolation valve at the tank with a blow out connection so if this happens again all you would need is a water hose.
 
Dec 2, 1997
8,709
- - LIttle Rock
I was told the previous owner had to get a diver to blow air up from the thru-hull to clear the blockage before. That’s why I’m thinking this is a common problem. I hope I’m wrong.
It's a common problem that's a LOT easier to prevent than it is to cure: After every pumpout, put a few gallons of water into the tank via the deck pumpout fitting, 'cuz that sends the water into the tank to stir up any sludge....open the thru-hull while you continue to add water several gallons of water.

If you're unwilling to do this at the pumpout dock AND if you have a washdown pump, go offshore and use the washdown pump to add water to the tank.

And btw, ALL holding tanks, whether your tank is gravity drain or not, should be flushed out to eliminate sludge 2-3 x season and especially in preparation for winter or other extended layup.

--Peggie