CD30 Holding Tank - Kracor

[John R.]

I spent two days removing the entire sanitation system from our '83 CD30. I don't want to disgust anyone with the details so we will skip that part and get to the point.

I was having a lot of trouble with head odor and thought it was the hoses and indeed they were permeated. They have all been disposed of along with the Forspar Y-valves which I do not recommend. They had a problem seizing over time and in fact the handle sheared off on one when trying to turn it. So much for the tauted strength of glass filled nylon (Marelon). I intend to complain to Forspar about the quality.

I removed the holding tank as well. It is a sculpted bow tank that fits under the V-berth cradled by the liner. I discovered after removing the tank that it had 5 cracks in it. All cracks were on the forward end of the tank. They radiated outward from the female tank fitting ports. Two cracks stemmed from the vent connection. Three others stemmed from the outlet fitting. The hose barb fittings are the blue/grey PVC type. All original parts from Cape Dory, installed by Cape Dory.

I phoned Kracor Inc. in Wisconsin (CD original supplier) and was faxed a sheet on how to repair cracks and holes in the tank. They advocated the use of polyethelene welding rods or thin strips of plastic milk containers (polyethelene also) and a heat gun or a propane torch. If you need the details of the repair procedure you can call them at the number I'll list below.

The gapping cracks in my tank can't be repaired properly in my opinion so I asked if they still made the tank and would they have a record of the particular model. I had a little trouble at first until I got to speak with an engineer. He was very helpful and was very concerned about the cracks. He is going to search their files for info on the CD.

The tanks are roto-moulded in aluminum molds when manufactured. They are made of high density polyethelene. The engineer has been there for twenty years and had never heard of nor seen cracks like these in those twenty years. He was mystified how they could occur, me too. I asked if over torqueing during install of the fittings could be the cause, he said no because the poly is used purposely to allow for expansion and flexing. He said over tightening would definately not be the cause. I asked if different thermal rates between the poly and the PVC fittings would cause it, he said no again. That doesn't leave much else because the tank has never been moved before. The vents were open and not blocked so pressure would not be the cause.

I would like to hear from anyone else that has had any problems with the poly tanks. Any particular tank, it doesn't have to be a holding tank.

I have decided that when I reinstall this system I will convert to a schedule 40 PVC pipe system rather than typical hose installations. In place of expensive marine Y-valves I'll use PVC ball valves that won't seize up.

If anyone else has converted to a PVC pipe installation I'd like to hear about your installation. I figure I'll need hot tub PVC to hose barb fittings to be able to connect the pipe to the head and vented loops. Any other ideas?

I'll post another message on this subject when I get the final tank information from Kracor such as model # and cost etc.,.

KRACOR INC.
5625 West Clinton Ave. (figures!)
Milwaukee, Wi. 53223
PH: 414/355-6335
FAX: 414/355-8782

[Steve Alarcon]

John,

I've had a common problem on all of my tanks on my '83 CD30. The problem has been that the nipples have all broken off. I have been able to glue them back on with a product who's name escapes me right now (I'll get it for you if you wish). But the point is that they have all broken for what appears to be a common reason....pressure. Seems like each of the tanks, (fresh water or holding tank) all had clogged vent lines. When filling or pumping into, the increased pressure would cause the male fittings to break away. Since I replaced all of the vent lines, no problems. Hope this helps.

Would really appreciate knowing what you find out about replacement tanks. I'd like to replace mine before I have "major" problems.

Steve Alarcon
CD30 Temerity
Seattle



alarcon3@prodigy.net

[Tom]

I spent two days removing the entire sanitation system from our '83 CD30. I don't want to disgust anyone with the details so we will skip that part and get to the point.

I was having a lot of trouble with head odor and thought it was the hoses and indeed they were permeated. They have all been disposed of along with the Forspar Y-valves which I do not recommend. They had a problem seizing over time and in fact the handle sheared off on one when trying to turn it. So much for the tauted strength of glass filled nylon (Marelon). I intend to complain to Forspar about the quality.

I removed the holding tank as well. It is a sculpted bow tank that fits under the V-berth cradled by the liner. I discovered after removing the tank that it had 5 cracks in it. All cracks were on the forward end of the tank. They radiated outward from the female tank fitting ports. Two cracks stemmed from the vent connection. Three others stemmed from the outlet fitting. The hose barb fittings are the blue/grey PVC type. All original parts from Cape Dory, installed by Cape Dory.

I phoned Kracor Inc. in Wisconsin (CD original supplier) and was faxed a sheet on how to repair cracks and holes in the tank. They advocated the use of polyethelene welding rods or thin strips of plastic milk containers (polyethelene also) and a heat gun or a propane torch. If you need the details of the repair procedure you can call them at the number I'll list below.

The gapping cracks in my tank can't be repaired properly in my opinion so I asked if they still made the tank and would they have a record of the particular model. I had a little trouble at first until I got to speak with an engineer. He was very helpful and was very concerned about the cracks. He is going to search their files for info on the CD.

The tanks are roto-moulded in aluminum molds when manufactured. They are made of high density polyethelene. The engineer has been there for twenty years and had never heard of nor seen cracks like these in those twenty years. He was mystified how they could occur, me too. I asked if over torqueing during install of the fittings could be the cause, he said no because the poly is used purposely to allow for expansion and flexing. He said over tightening would definately not be the cause. I asked if different thermal rates between the poly and the PVC fittings would cause it, he said no again. That doesn't leave much else because the tank has never been moved before. The vents were open and not blocked so pressure would not be the cause.

I would like to hear from anyone else that has had any problems with the poly tanks. Any particular tank, it doesn't have to be a holding tank.

I have decided that when I reinstall this system I will convert to a schedule 40 PVC pipe system rather than typical hose installations. In place of expensive marine Y-valves I'll use PVC ball valves that won't seize up.

If anyone else has converted to a PVC pipe installation I'd like to hear about your installation. I figure I'll need hot tub PVC to hose barb fittings to be able to connect the pipe to the head and vented loops. Any other ideas?

I'll post another message on this subject when I get the final tank information from Kracor such as model # and cost etc.,.

KRACOR INC.
5625 West Clinton Ave. (figures!)
Milwaukee, Wi. 53223
PH: 414/355-6335
FAX: 414/355-8782

Just a comment on welding polypropylene tanks. Where I work we have a fleet of polypropylene kayaks that we rent out and have to repair cracks from time to time. You may get a different kind of plastic rod and perhaps the material is different, but for what it's worth here's my experience. You don't want to ever put the heat gun or propane torch directly on the tank. If you overheat it it blisters up and you have a problem getting the rod to stick. Unlike welding metal you DON'T heat both and then fuse them. Think of the rod as you would a glue gun. You heat only the rod until it melts and let it drip down on the tank. Try to get a big gob melted all at once because it's hard or impossible to go back and add a little more later. Once the weld starts to set up you can't reheat it without getting the tank hot and deforming it. Once you get a gob on the tank, very quickly work it around with a putty knife. When it hits the cold tank it starts to harden almost immediately so you don't have much time to work it. I can't imagine that a propane torch would work. I think it's way too hot.

Practice on something before you try the tank. I don't think you will be happy with it. I've never seen a patch hold as long as a year. Of course kayaks take a twisting and beating that water tanks or er.... effluent tanks don't so maybe. If you have a tank that's removable I'd take it out of there and replace it. They're not expensive and what a drag to have to do it again in a year.

My own theory with no evidence to back it up, is that when you attach the rather stiff hoses to the tank, they become a "hard spot". As the boat moves, the liquid is sloshed back and forth and flexes the tank up and down and back and forth even though there is no pressure. Just like bending a nail back and forth, after a number of years the tank cracks at the hard spot. You can put some welding rod on the crack but then IT becomes a hard spot and the tank starts working just beyond the edge of the weld. Pretty soon you have a new crack and the welding rod doesn't stick to itself once it's been melted and cooled as well as it does to the tank material. Before you know it you've got bad patches on top of patches and all of them are leaking.

JMHO but I'd get the thickest walled new tank I could, secure it really firmly, and be done with it for awhile. I replaced all the plastic pipe on my boat with hose, but if you want to go with PVC pipe why not get the schedule 80 rather than schedule 40. Schedule 40 is meant for sprinkler systems where there is no hot water and a leak doesn't matter. Schedule 80 (the gray stuff) hardly costs any more but the walls are twice as thick, uses a heavy duty glue, and is approved in most states for hot water. This means it stands up to expansion and contraction better than schedule 40. You probably knwo that when gluing PVC you have to push in really hard on the two pieces and hold for awhile until the glue sets. The first push on the tubing seems to bottom the tubing in the fitting, but there is a stop there that you are meant to push through and hold to get a leak tight joint.

Don't take my word as Bible here. I don't pretend to be an expert. I'm just relating my personal experience working with the material a little bit, in hopes it will help. I've never dealt with Krakor and maybe they have something and know something that I don't, but my experience is that over optimism about what tank repair rod can do is more the rule than the exception.

Good luck with your project and we always appreciate it when people take the time to post the results of whatever they try. Cracked tanks are a common problem and a successful cure would be great to know. Oh yeah, BTW both of my water tanks are leaking -- cracks right around the bases of the fittings that accept the hoses. Just small leaks and mainly when you're heeled over so I just live with them. You wouldn't want to live with a leaking holding tank...



TomCambria@mindspring.com

[Michael Stephano]

I had a simular problem with my water tanks (CD30 K). There were cracks around the vents but it apeared to me that they were caused by a poor installation. The vent line was supporting the tank through the hole drilled in the hanging locker (strbd side)Also both my drain fittings had broken at some point in time and were also cracked around the fittings. I repaired the cracks with a soldering iron and put expandable drain plugs in. So far the repair seems to be holding. I can not explain why the drains were cracked perhaps it was not winterized correctly or something. The good news is it was easy to repair.



mundo@visi.net

[Anthony P. Jeske]

John:
I too had cracks in the holding tank on my CD28. I ordered a new tank from Kracor. It was not too expensive, but as I lived in the Milwaukee area I didn't have to pay freight.
It looked to me as if the fittings had been overtightened when they were installed by the factory.
Tony Jeske



ajeske@ixpres.com

[John R.]

Thanks for the responses everyone. I will keep all ideas in mind. I do not intend to repair the tank as I feel that is an exercise in futility. I will post all new info as I receive it from Kracor. I faxed them drawings with measurements of the tank today and hope to hear back tomorrow.

Kracor engineers insist that the tanks can be repaired by utilizing a heat gun or a propane torch. That's their idea not mine. I suppose with experience that is acheivable or they would not be recommending the practice. I'm sure they would rather sell a new tank than furnish free repair advice and instruction sheets. They appear to be a good company and I encourage anyone with tank problems to contact them and speak to someone in the engineering department.

After closer inspection today I believe my vent lines could have had a blockage at one point in time at the tank end of the hose. The fitting shows signs of a past crusted condition. Perhaps the blockage dislodged while I struggled trying to remove hoses. That opens the case for possible excessive pressure causing the cracks around the fittings. I think this could be quite likely. I intend to obtain a tank with larger vent line connections.

I do not feel that the motion of tank contents could cause the type of fractures I see in the tank because of hard connections. The tank is firmly secured and would not shift enough to cause enough strain at the fittings for the flexible hoses to cause cracking to the degree I've witnessed.

Another item worth mentioning for CD30 owners is that you must remove the main salon door and the V-berth door to remove the bow holding tank from the boat. Another one of those "stick it in then drop the deck on" installations! Owner friendly, eh?

To reiterate, the engineer Dave Green at Kracor stated that the assembler at Cape Dory could not have caused the cracks by overtightening because of the flexible nature of the polyethelyne material. According to them that material is specifically used to prevent that sort of problem from occuring.
Hmmmmmmmm..........Thanks all.

[John MacArthur]

Most of the fittings in my 30 water tanks, including the spares that had plugs in them, were cracked, apparently from overtightening. (engineers opinions notwithstanding) These are discs of thicker material that is welded into a hole in the side of the tank, and without exception, they were cracked around the outside of the disc that stuck through the tank wall. I was lucky enough, in the case of the spare fittings, to get away with pulling off the broken off piece, retapping the hole, and lightly screwing in a new plug. The supply and fill fittings, I have to deal with next, as they all leak a little. Incredibly fortunately, I don't seem to have the problem on the holding tank. My 30 is an '82, and it sounds as if this is not an uncommon problem. I would bet against the engineers (they aren't infallible) that there was a hamfisted installer working for Cape Dory around then, who overtightened everything.



jmac@laplaza.org

[John R.]

I'll be speaking with Dave Green at Kracor today and I will make a point of conveying all the comments other owners have regarding the tank failures in their boats. The cracking around the fitting seats is obviously becoming a common denominator for many.

I will request that they review the comments regarding their tanks on this web site. Perhaps with our comments and their assistance we can come to a definative conclusion as to what has caused the multitude of cracked tank ports. Hopefully we will be able to arrive at a solution.

My potable water tanks are fine, and there are additional watermaker feed lines to the tanks in addition to the usual fill, supply and vent lines.

It seems that boats in the '82 and '83 production years are having the problems. If anyone owns a earlier or later model (any size) that is having the same problems please post a message.

[John MacArthur]

I'll be speaking with Dave Green at Kracor today and I will make a point of conveying all the comments other owners have regarding the tank failures in their boats.

Excellent idea! For the record, I'd like to say that the fittings are not "exploded", such as would happen from the plug expanding the fitting too much, but "pushed away" from the side of the tank, such as would happen from the threaded portion of the hole being too shallow, and the plug "bottomming out" in the threads. Continued tightening at this point apparently resulted in the cracking around the fittings.



jmac@laplaza.org

[Bob Emmons]

I spent two days removing the entire sanitation system from our '83 CD30. I don't want to disgust anyone with the details so we will skip that part and get to the point.

I was having a lot of trouble with head odor and thought it was the hoses and indeed they were permeated. They have all been disposed of along with the Forspar Y-valves which I do not recommend. They had a problem seizing over time and in fact the handle sheared off on one when trying to turn it. So much for the tauted strength of glass filled nylon (Marelon). I intend to complain to Forspar about the quality.

I removed the holding tank as well. It is a sculpted bow tank that fits under the V-berth cradled by the liner. I discovered after removing the tank that it had 5 cracks in it. All cracks were on the forward end of the tank. They radiated outward from the female tank fitting ports. Two cracks stemmed from the vent connection. Three others stemmed from the outlet fitting. The hose barb fittings are the blue/grey PVC type. All original parts from Cape Dory, installed by Cape Dory.

I phoned Kracor Inc. in Wisconsin (CD original supplier) and was faxed a sheet on how to repair cracks and holes in the tank. They advocated the use of polyethelene welding rods or thin strips of plastic milk containers (polyethelene also) and a heat gun or a propane torch. If you need the details of the repair procedure you can call them at the number I'll list below.

The gapping cracks in my tank can't be repaired properly in my opinion so I asked if they still made the tank and would they have a record of the particular model. I had a little trouble at first until I got to speak with an engineer. He was very helpful and was very concerned about the cracks. He is going to search their files for info on the CD.

The tanks are roto-moulded in aluminum molds when manufactured. They are made of high density polyethelene. The engineer has been there for twenty years and had never heard of nor seen cracks like these in those twenty years. He was mystified how they could occur, me too. I asked if over torqueing during install of the fittings could be the cause, he said no because the poly is used purposely to allow for expansion and flexing. He said over tightening would definately not be the cause. I asked if different thermal rates between the poly and the PVC fittings would cause it, he said no again. That doesn't leave much else because the tank has never been moved before. The vents were open and not blocked so pressure would not be the cause.

I would like to hear from anyone else that has had any problems with the poly tanks. Any particular tank, it doesn't have to be a holding tank.

I have decided that when I reinstall this system I will convert to a schedule 40 PVC pipe system rather than typical hose installations. In place of expensive marine Y-valves I'll use PVC ball valves that won't seize up.

If anyone else has converted to a PVC pipe installation I'd like to hear about your installation. I figure I'll need hot tub PVC to hose barb fittings to be able to connect the pipe to the head and vented loops. Any other ideas?

I'll post another message on this subject when I get the final tank information from Kracor such as model # and cost etc.,.

KRACOR INC.
5625 West Clinton Ave. (figures!)
Milwaukee, Wi. 53223
PH: 414/355-6335
FAX: 414/355-8782
This is in respnose to the holding tank problem, experienced by

John R. I too have a crack in my polyethelene waste tank, however
I think that I caused it by putting too much pressure on the 1 1/2"
tank discharge fitting when I replaced all my hoses in my CD30. I
used the heavy duty wire reinforced hose which put alot of pressure
on the nipple. Anyhow, after some research, I have discovered that
welding a polyethelene patch is not a sure thing, there could be a good chance that it could leak. So I opted to have a new tank
manufactured by Tank Depot. Robin Jones, the owner of this company
told me to ship him the old tank and he could make a duplicate.
His phone number is 401-941-8151, and his business is located in
Rhode Island.
Best of Luck
Bob Emmons "Red Wing" CD30



remmons@hamilton.k12.nj.us

[Olli Wendelin]

My 1977 CD30 also had a tapered tank under the v-berth. It was set up as a water tank. The top had several cracks in it and I threw it away a couple of years ago.

If you come up with a source for a new tapered tank I would be interested.

Olli Wendelin
BLUE MOON
Charleston, SC

[John R.]

Bob,

Sounds like good news to me, just a couple of questions though.

Did you actually have the tank made?

What is it made out of? Polyethelene?

Does it have seams? How thick are the walls?

How many $$$ and how long to make it?

Thanks a lot for your feedback.

This is in respnose to the holding tank problem, experienced by

John R. I too have a crack in my polyethelene waste tank, however
I think that I caused it by putting too much pressure on the 1 1/2"
tank discharge fitting when I replaced all my hoses in my CD30. I
used the heavy duty wire reinforced hose which put alot of pressure
on the nipple. Anyhow, after some research, I have discovered that
welding a polyethelene patch is not a sure thing, there could be a good chance that it could leak. So I opted to have a new tank
manufactured by Tank Depot. Robin Jones, the owner of this company
told me to ship him the old tank and he could make a duplicate.
His phone number is 401-941-8151, and his business is located in
Rhode Island.
Best of Luck
Bob Emmons "Red Wing" CD30