Seeing how the holding tank is basically immovable due to the bulkheads, it is difficult to know if it is caked with crud on the bottom! I expect it is. I bought a 6" beckson port for inspection and cleaning. Before I go into this task, I would like to see if others have done so. On my last boat, I had in inspection port, but I could also lift up the tank to fully empty.
Paul,
Did the inspection port many years ago. Called the tank company about what sealer to use. They told me "DAP" gutter seal. have done both holding and water tanks.
When you do the holding tank, do it on a windy day...
Hmm, unless you had a holding tank with the "drain" at the bottom at the lowest point (i.e. under the tank), I would suggest that it is physically impossible to completely drain any type of tank, let alone a holding tank where the heavier bits can settle to the bottom. Even then, the hose would sill have stuff in it. I would propose that all our tanks all have some "crud" on the bottom. As to how "caked" on it would be, would depend on the nature of the tank surface, how often you pump out and how well you pump out. During the sailing season we try to pump out every weekend. And when we do, we also flush fresh water in through the vent as the attendant is sucking out at the other end (out vent is at the forward end of the tank and the outlet at the aft). This works for us because it flushes the length of the tank. The attendant can also see when the color changes of what they are sucking out (they've got a short clear bit in their hose). At the end of the season we flush it several times and then with some anti-freeze. I've known people to take their boat into the waves just to "rock" it for a bit before doing the final suck out.
I've heard of some people having an access port to their holding tank, but I wonder about the logic behind it. I personally would want to minimize the number of potential openings/outlets in this particular type of tank. I really want the stuff inside to stay there, and I have no interest in interacting with it. I guess we've also never I my fifty years boating had a boat with an access port to the holding tank. I know I've never had a reason to get into it, nor do I remember my dad ever needing to get into it. So I guess I am wondering why people want to get into it?? If its cruddy inside, so be it. It's a holding tank!
You mentioned that you were able to lift up your old holding tank. I'm surprised and a bit concerned. Your holding tank should be fairly well secured. The last thing you want when sailing in heavy seas, or get caught in a knock down, is to have your tank knocked about and potentially spill its load! Personally, I would make sure its went tied down and immobile.
There isn't much holding that bit of plywood aft of the tank to the hull. I removed mine and did not put it back in.
In my opinion the task at hand: crud in the bottom of the tank, does not have a maintenance schedule that warrants cutting a hole in the tank
and having yet another point at which smells can emanate into your saloon.
I also recommend removing the tank for a thorough pressure wash inside and out. Where you can then paint the compartment with bilge coat, I painted the tank with plastic primer and oil alkyd rustoleum. I found the source of stench from my tank was actually the compartment, not the tank. I used ballistic nylon strap and two screws to hold the tank against the forward bulkhead.
On a lesser note, you don't want to do that cleaning operation inside your boat... you'll wish you'd removed it about 5 mins into it.
Make sure you get enough thread sealant and don't use tef tape, just don't. Use a greasy, flexible, non drying type of pipe thread sealant.
Plastic fittings cannot produce the pressure needed to make tef tape effective. If you achieve this you will split your fitting.
Hope that helps!
You could also simply take your vent hose fitting off and look inside and see what's there. Before you engage in more destructive installations.
Am I the only one that can't stop chuckling? What do you think is in there? Go ahead......surprise me.
The reason I am contemplating this is so I could reach in and clean the tank. Believe me I am gagging just writing those words. At least start out with a clean tank. I took ownership of the boat last year. All the lines to the tank were caked which I replaced. I would get a horrendous stink when flushing. I just replaced the vent hose, see what that does. The thinking is this - I can't imagine it would stink as much as it did last year with a clean tank. I didn't learn about the fresh water flush until the off season. Judging by other things on the boat, I can't imagine the PO ever cleaned the tank.
I am going to look at removing the bulkhead once more.
Paul, I trust you may have read the "101 Topics" about head odors. It covers the vent smell quite well. Often the lines can be clogged while the tank remains just fine because of the sloshing of the contents. I still recommend checking before dismantling. Good luck.
I just went through the 101 topic on odors... lots there, but not about the vented gas from the stantion vent.
The only thing I found that reduces that odor is lots of that blue stuff for RV holding tanks. Or only use the head on the "POTTY TACK" so the wind won't carry the expelled gas through the cockpit. I've been tempted to move my vent to a through hull below the rub rail but it seems like a lot of work for 50/50 chance you won't smell the gas in the cockpit.
When someone flushes water goes into the tank and displaces air which comes out the vent. Nothing is going to change that. I moved my vent forward and below the rail (the new vent hose goes into the port vberth locker and out). Odor still wafts back to the cockpit when someone flushes. I'm using Odorlos? Odorless? Something like that, and it helps. A couple of years ago I installed a tank sensor. I forget the brand, but it is one of those things that has three little floats that extend down into the mucky goo. A hole 2" to 3" in diameter was needed through the top of my tank, with a screw in fitting of the same diameter. This sensor has proved to be one of the best livability improvements I have made--no more guessing how full the tank was. They aren't terribly expensive. If you are going to cut a hole into your tank, might you consider a 'two birds with one stone (or hole)' approach?
Quote from: Indian Falls on April 26, 2014, 09:17:47 AM
I just went through the 101 topic on odors... lots there, but not about the vented gas from the stantion vent.
Head Odors 101.2 The Difference between KO & Odorlos (scroll up to Reply #2) http://forums.catalina.sailboatowners.com/showthread.php?p=890493&highlight=odorlos
This is in the wiki, too:
http://www.c34.org/wiki/index.php?title=Marine_Sanitation_Fact_and_Fiction
I have thought about putting the vent 10-15 ft up the mast to keep the odors off the deck but have not figured how to do it and keep the vent hose going in an upward direction and not have to step over it or duck under it.
Dave, try this instead of going up the mast with your vent:
I screwed a fitting into the hole in my stantion and put a 3/8 vinyl tube over the side a few inches above the water.
The gasses escaping the tank when the head is flushed tend to stay low and out of the reach of crew and passenger nostrils. Take the hose off when you leave the boat.
I also found that I needed a shot of great stuff up inside the stanchion above the vent to stop the gasses from exiting where the lifelines go through.
I relocated my vent to a thru hull located below the rub rail. While underway, we don't get a blast of odor when someone uses the head. Usually it's worse at anchor if someone is using the head.
When we purchased our boat the holding tank was quite pungent. Rather than replace with plastic , i replaced with stainless steel.
No more odours at all.
I will not get in to too many details about removing the old tank.
I agree with others .. you do not want to be sticking your nose in there.
Hmmm? I would think the switch to stainless tank, in itself, would not make a difference? I have not heard of the actual plastic tank permeating odors. But perhaps? Did you change anything else along with the tanks; (hoses, vent size/location) ? If so, more likely those are the reason(s) for "no more smell"? My guess.
Quote from: Jeff Tancock on April 25, 2014, 10:26:29 AM
Am I the only one that can't stop chuckling? What do you think is in there? Go ahead......surprise me.
"One man's trash is another man's treasure".
Andy,
You couldn't have rid yourself of odors only by having a ss tank.
How can that be possible?
Please elaborate on your regimen or any tank vent modifications.
Thanks!
Thanks all for the input. You talked me out of the port in the tank. After a second look, I agree that it wouln't take much to cut free the tank for removal. Now, before I do, I am thinking of best way to resecure it after reinstall. I would rather not get into a strap.
Paul, Frederick wrote up what he did in great detail.
Frederick and Dan gave different advice, but, your boat, your choice.
ITWMB, I'd throw some ice cubes in through the vent fitting and go sailing on a boisterous day. I've looked into our 27 year old tank and there simply isn't that much down there. Really. Just tryin' to save you unnecessary work.
Paul,
Cory and I both replaced our holding tanks (installed them in 2012). This thread covers much of the back and forth banter: http://c34.org/bbs/index.php?topic=6593.0 (http://c34.org/bbs/index.php?topic=6593.0) . I haven't completed writing the entire thing up, but when done, I'll post the link here. Peggie Hall was a wonderful resource and provided much advice. Basically the smell comes from anaerobic bacteria that grows in the absence of oxygen, thus the need for good ventilation (aerobic bacteria apparently doesn't smell). So ventilating your tank should keep the smell down. Having a larger diameter vent hose, of a properly rated hose, with minimum length and bends in the line, all equate to better ventilation. Some have even had two vent lines put in (to cross-ventilate) the tank. I had planned to do that, but in the end decided on just the one (routing the second was proving difficult).
I'd be careful about stainless steel tanks as well. There is a lot in this forum to find on holding tanks. Use the Google search "holding tank site:c34.org".
Cheers, Fred.
i also replaced the head and discharge hoses with the white hose and also the vent hose .
Vent hose vents through a thru hull just below the rub rail
We are also in the habit of pumping out upon return to the marina.
FYI, just because the hose is white, doesn't mean that it's the odorless type. There are different grades of hoses weather they be white or black. There was an article written by Peggy that gives the best hose to use. There is also info in the West Marine catalog.
Mike
I put a see through 3" port on top of my tank about 5 years ago, no problems no leakage, just look in there with a flashlight once in a while to see how full it is getting, and every fall I pump and flush tank, remove the port cover and give the tank a good flush with a garden hose and shop vac the remaining water, very little smell in boat while doing this, I don't see any problem whatsover in installing and maintaining your port
Bob, what did you use for a sealant putting the port in?
You could probably use Plumbers Putty. You can get it at HD or Lowes. Is waterproof and seals well but doesn't harden or dry out. Plumbers typically use it for sink drains.
Hi, sorry I took so long getting back to you, I believe I bedded the port with 5200, very happy with the results, and the ability to look through the port with a flashlight is a plus with me, I like the ability to get in there and really clean after a pump out in the fall.