Holding Tank Relocation CD31

[distand]

Now that I have confirmed a holding tank leak on my recently purchased CD31 (see my recent positing regarding a holding tank leak) and things have been cleaned up I am starting a new message regarding relocating the tank.

I have read some of the older posts and I saw that Robinhood Marine had suggested installing a tank within the cavity of the existing tank. That was my thought too but after talking to my yard about it seems like it could be difficult and expensive. I have also seen that some have chosen to repair the existing tank with a variety of ingenious methods. I'm not planning on doing that immediately - maybe down the road. As this is a new boat for me I am motivated to launch it and have some fun sailing before I tackle anything too complex.

So I wanted to see if any CD31 owners had any specific experience with abandoning the built-in holding tank and placing a new tank somewhere else. It would be great to hear where the tank was installed, size of the tank, any issues that came up (e.g., vent location, cleanout location, smells in the cabin, etc...). By the way, my boat does not have the option to discharge over the side. Seems like it would be a nice option to have because I could easily clean out the tank when offshore. If anyone has converted their system to allow over the side I would be interested to hear how it was done (without a new thru hull). Thanks in advance everyone

Don

PS: I'm in the process of renaming my CD31 so I will update the registry when I have things squared away.

[Phil Shedd]

Don

You might search items by Dean Abramson . Dean had a leak in his holding tank and posted a great post on how he repaired it . There were lots of pictures. If the post is gone try a PM to Dean

Phil

[Jim Walsh]

Just curious, where did you find the leak and how did you locate the exact source?

[Dean Abramson]

Hi Don,

I indeed am a veteran of these wars...

See the thread:
http://www.capedory.org/board/viewtopic.php?f=1&t=20767
That thread will give you the lowdown.
The hyperlink in the thread is no longer good, but I have just now reposted three of the pix at:
http://www.mainephoto.com/folios/notsof ... index.html
You can see my ad hoc tools, the bilge bottom after a colored water test, and my bilge after I completed the repairs.

Also, I had an article in Sail, in the January 2013 issue, which, in part, is a humorous take on this project. A sense of humor helps. The article is called Do It Wrong, and starts on Pg. 60.

For the sake of full disclosure: the repair lasted about two years, and far as I could tell, it was going to last forever; I had no more problems related to that issue. However, our boat was subsequently damaged in an accident, and I had to have some hull repair done that involved cutting into the hull at the bilge. So while that was going on, I asked the boatyard to get in there and fix the holding tank right, because at that point it was a lot cheaper than if it had been a separate job. So we bit the bullet and did it. That professional repair has lasted, and I am sure will last for good, because they put a lot more glass in there. (The larger hull repair was done well too, and no more issues there either.)

I will post this also in your other thread. Seems like a lot of 31's have/had this issue with the original HT. It's a bad design, I'm afraid, on a boat that is so, so nice in almost all other ways.

[distand]

Regarding finding the leak, actually I had the yard at Noank Shipyard do it. They cleaned out the tank and bilge (which had quite a lot of holding tank waste in it). Then they filled up the holding tank and observed water seeping into the bilge. The exact location of the leak was not determined. However, the yard manager, Denny, made a good point that the weak point in these types of glasses tanks is in the corners. While fixing it is possible (as was done by some other CD31 owners), he did not think a repair would hold up. I was on the boat today and the odor is much improved.

I responded in my other thread (Holding Tank Leak) where I'm planning to put a new holding tank.

[eb1smith]

I too have had this issue. My fix was to use copious amounts of 5200 on the joints that connect the holding tank to the bilge, I think I used 4 tubes. No issues after over 3 years.

Anyway if you are looking at relocating, the options would be:

1. Right behind the toilet.

2. In the cabinet next to the head.

3. Under the settee, change out the water tank for the holding tank.

Also you could change over to a Wag Bag.

--Eric
CD 31

[distand]

Thanks Eric. I hadn't thought of the two obvious places. Behind head and in cabinet. I will look into some tanks that might fit there.

Don

[distand]

Finally some time to reflect on my "little" project to fix my holding tank. After a lot of consideration I decided to repair the tank this past winter. Here is a very short summary of what I did (I would be happy to provide any details to anyone):

- Poked around via the bilge hatch using a knife taped to a stick. It became immediately apparent that the bulkhead to tank had become loose where it meets the bottom of bilge.
- Used a 4 1/2" grinder with 40 grit disk (mounted it on various custom handles to reach bottom) to remove material at bottom and to open up the bottom of the bulkhead to help with repair
- After struggling with how to reach the repair I made the decision to cut a larger bilge hatch (cut about 30" long x 14" wide opening that allowed me to remove the entire sump basin (built into bottom of floor). This worked fairly well and the new hatch came out after much cutting with a small circular saw, multifunction tool and hand saw.
- This access enabled me to kneel on the raised portion of the bilge (i.e., on the leaded portion) and to reach down to the repair area. After some more sanding/cleaning I was satisfied with condition to begin repair.
- Cut/fit several layers of chopped mat, bioaxial cloth and roven woving using polyester resin (need a good mask). I layer up the entire bottom of bilge with chopped mat and then proceeded to use bioaxial to patch up the bottom of the bulkhead. Several layers later the patch seemed very solid.
- Then I installed a 3/4" marine ply lip on the underside of the floor to hold the new hatch. I used epoxy and SS wood screws inserted from bottom up. Although this made a very solid lip for the hatch, given the location of the hatch just below the companionway ladder I wanted to make sure that it was very solid. So I installed three bulkheads beneath the lip and supporting the width of the hatch. Very time consuming to construct these but definitely worth it. I installed them with SS angle irons connected to bottom of floor. Decided to not fiberglass them in (for now) as they were very solid. Used closed cell foam on edges against hull and on underside of new bilge hatch.
- This is just a short summary. There was much shaping, sanding and fairing involved and this job required a real commitment of time.
- Re-plumbed the toilet, made some improvements to bilge pump, installed a sump pump (was missing) and installed the hatch. It is screwed down so it can be easily removed.
- I launched the boat (from Piermont, NY) in July and sailed it around NYC up to home port of Noank NY. Happy to report that all is working well and there are no leaks!!!! Like all things I will have to see how the repair holds up over time.

Don

[rorik]

My boat is smaller than yours, a CD28.
I replaced the leaky, partly solid tank not long after I bought Mathilda.
The new tank is a smaller rectangle than the original origami shape and is located behind the head on the port side, rather than under the forepeak.
The hoses are much, much shorter, it's easy to get to, it has an access port for cleaning, and what weight there is to the tank, is not up in the bow.

My .00002

[Jim Cornwell]

Leaking holding tanks appear to be common among our 31's. Yankee allegedly had a nasty problem just before I bought her in '07. With eyebrows raised, the PO's yard foreman described the repair as having been "expensive!" Foolishly, I didn't inquire what the repair entailed, so here's a question. Is the tank simply separated from the bilge by a transverse fiberglass partition? What does the geometry look like? So far, so good for me, but I'd like to know what to watch for. Jim.

[Jim Walsh]

My holding tank does not appear to have ever been repaired. Hopefully it'll go another thirty years and never draw attention to itself

[distand]

The tank is just a cavity in the aft section of the keel beneath the engine. A fiberglass bulkhead separates it from the bilge area. When you look into the bilge the bulkhead or partition is visible. Mine has a vertical stripe that allows you to see the level of waste in the tank (difficult to see though). On mine with the bilge dry and liquid in the holding tank I could see some seepage coming out along the bottom (where the partition attached to the bottom of the bilge).

I never found out what caused the cracks/leaks in the bulkhead in the first place. If I had to guess I would say freezing may have caused it. I plan to thoroughly clean/dry before the winter and then add some antifreeze to prevent the problem (fingers crossed).

Don

[wsonntag]

Just a note on this topic - I believe I had a very slight leak from the holding into the bilge. I fixed it quick and easy using a specialty epoxy sealant designed to be used to line sewers, concrete gutters and fitments associated with abattoirs, food processing plants. I dried out the bilge best I could, mixed up the stuff (in an ice bath to keep it from kicking too fast on a hot day), poured it into the bottom of the bilge used a simple paddle on a long stick to spread the oozing stuff evenly on the bottom of the bilge and up the sides three or four inches, it has bonded very tightly and not separated from the surface of the bilge over the years. The material is designed to stick on damp, oily, greasy vertical surfaces. I did this quite awhile ago, never a problem again. Here's the text of my post from 2008.

"I would like to share the contact information for a firm that has supplied me with some helpful epoxy product. Progressive Epoxy Polymers http://www.epoxyproducts.com has sold me “Wet/Dry 700 Epoxy” that I have used to seal the bilge of my CD 31. Reading the posts on this Board regarding leakage from the integral holding tank in these boats convinced me that I was having the same problem or at least needed to exercise precaution.

The material is tailor made for this application. The description: “…a Kevlar reinforced epoxy coating system designed for coating and repairing surfaces that may be subjected to constant immersion in water, works underwater…..Wet/dry 700 will bond to water saturated concrete and is resistant to sewer gasses, pool chemicals, sulfur based chemicals, dilute acids and most caustics, and most hydrocarbon solvents (diesel, mineral spirits, etc)” “Uses include, swimming pools, marine environments, docks, fiberglass and wood boats, sewers, tunnels, dams, spillways, steel and concrete piping”

As with any catalyst epoxy temperature control to regulate how fast it kicks is necessary. I found out the “hard” way when my first test batch kicked in the pot and landed in a cowpie like lump on the surface I was coating. An ice water bath for the stuff in summer temps should work.

Although I am not an epoxy expert the firm has a good many useful products on the website, they have answered my email questions helpfully, quickly filled my orders and the product I purchased has exceeded expectations. Its amazing oatmeal thick stuff that bonds like crazy to less than pristine fiberglass."

Hope this is of some interest. Fun with boats!

Bill Sonntag

[Jim Walsh]

Thanks Bill, that's a valuable resource. It's nice to hear that a product worked as advertised, takes the guesswork out of which product to choose. That's what makes this forum great.