Replacing holding tank

Alex got it right. I used a 1 inch hole saw and cut out the embedded nuts under the tank. Then inserted a 1inch rubber bilge plug . Sealed it with marine tech . I cut off the t-handle of the plug and used a rubber mat to give clearance to the remaining stud from the plugs , so they would not touch the hull.
 
Well, let us know if you end up with a bilge full of crap the first time you hit a big wave. Or, if the vacuum pump cycles too frequently. Those will be the true tests.
 
Well, you're a braver man than me! Keep a close eye on it - Marine Tex does NOT bond with polyethylene. It might "stick" a little bit, but you would have at least had to severely roughen up the surface to, at best, get a moderate physical bond. It does not chemically bond - which is what would be needed. You might very well get a long life out of this repair... but have you ever met Mr. Murphy? You know that if he does show up, you'll be miles from anywhere when you notice - and at that point the entire tank would of leaked out and sloshed around your entire bilge area (and it surely won't just leak straight down to under the engine, either). That was the reason I just went ahead and bought a new one.

There was a post above about selling an extra one - seemed like that was almost too good to be true. How often do you find someone that has a new tank just sitting around!

Oh well, good luck... and remind me to always stay upwind of you! :smt001
 
I follow what you did..I think..and believe it will work.
Your worst case is the plugs might seep over time but, can't blowout to a "geyser" due to them being on the bottom of the tank.
You will know if its leaking buy any scent in the ER.
Heck if it leaks after a few years (or minuets) you can always spend the $750 for a new tank.

Ensure your vent line is clear because, you don't want to pressurize the holding tank.
I'm wondering if the center bolt material will hold up overtime to the black water in the tank.
I have no idea how corrosive that stuff is..?

That said, I would have replaced it with a new one on my boat...but, might have tried something like that on someone else's boat.

Congratulations on your ingenuity and ability to think outside the box...might prove to be better than new.

Best of luck,
 
I had the marine mechanic pull my 28 gallon holding tank out of my 2001 260 DA. Even after I pumped it out he said there was 6" of liquid in tank, don't know why because this hose is powerful. Anyway, I have to go down tomorrow and look at it, he said It has 4 rubber feet underneath and one is leaking. I won't understand what he's talking about till I see it tomorrow. What I want to know is since poly propylene can only be repaired with the same material, how did marine tech adhere to the tank? I wish you had pictures.
 
Cod Father said:
I had the marine mechanic pull my 28 gallon holding tank out of my 2001 260 DA. Even after I pumped it out he said there was 6" of liquid in tank, don't know why because this hose is powerful. Anyway, I have to go down tomorrow and look at it, he said It has 4 rubber feet underneath and one is leaking. I won't understand what he's talking about till I see it tomorrow. What I want to know is since poly propylene can only be repaired with the same material, how did marine tech adhere to the tank? I wish you had pictures.
Click to expand...

It doesn't, that's the point. A repair like this might last quite a while, or it might last 2 days. It's a gamble. There's a possibility of corrosion, rubber breaking down, even the plug getting sucked into the tank.

There's no "rubber" feet. But there are "feet" that were used in the mold making process. Those the spots that crack and leak.

6" of liquid remaining... could be he was guestimating wrong, or had the tank slightly tilted. Or, the dip tube could be cracked/broken. You'll never get all of it out, but maybe an inch or two. Not 6", normally.
 
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I drilled mine out then ran a 3/8 npt tap and put in a plastic plug it held all season so far.
 
Hey Eddie I bought the holding tank and turns out I don't need it. You can text me at 631 988 8268
 
It's been 1 year since I repaired my holding tank and it is still holding perfectly. Again I drilled out the bottom nuts, where the leak was coming from with a 1 inch hole cutter ,then I installed a 1 inch seacock plug ( twist on) applied marine tech and inserted them in the 1 inch holes I drilled. Let it dry. Cut off the remaining stud( exposed stud) and placed a 1/2 inch rubber mat under the tank so the plugs would not rub on the hull. So far so good . I spent less than 50 dollars for the repair, a lot better than 1200.00. If you have any questions call me 786-246-3637
 
Sal,

I called you today. I just saw your post. My number is 703-626-7625. Please let me know if you still have that holding tank and how much you'd like for it. Thanks!

Eddie
 
Water U Lookin' At said:
Sal,

I called you today. I just saw your post. My number is 703-626-7625. Please let me know if you still have that holding tank and how much you'd like for it. Thanks!

Eddie
Click to expand...
This is how i fixed my holding tank on my 2001 280.
Pulled the tank same thing leaking by bolt insets, put in a course 3/8 bolt loaded with silacone and cut off the rest of the bolt. Wah lah Done!!
 
This job is a must do for me this year for a couple of reasons. The tank was creased due to too much vacuum on a pump out and is apparently has a slow leak. The other issue is that when Sea Ray assembled this 300 SD. They put the pump in front of the tank. Not only can I not see it. I can not get to it without removing the tank. I have already removed the water heater and now have plenty of access to remove the tank.

Does anyone know how expensive a replacement tank is? The reason I ask is that Sealand makes a tank with the pump attached. However it is about a grand. If I replace the tank with one in kind. I may be able to modify the bulk head with an access panel so I will be able to service the pump. I am just looking for a ballpark cost if anyone has it.

Thanks
 
I don't remember the tank price (alone) off hand from when I replaced mine. But remember thinking, at the time, it wasn't worthwhile since the "loaded" tank wasn't a whole lot more. It just made sense to me to do the whole thing since the motors and such were all original, anyways. Try calling Northeast Sanitation.
 
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Thanks for the input. It looks like for the size tank I have it will be under 350$. I may look into a rectangle tank vs the cube and move the pump to the side of it.

Thanks again.
 
Does that come with new seals, as well? You'll, at bare minimum, want to replace those, as well. It'd be a shame to go through all of this and not do that. As far as removing the tank, pretty easy - just remove the thimbles from one side only and slide it out.
 
I have a 28 gal sealand 28 hrs tank. the sandbar if you need it I can text you pic


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