Hunter Legend - Waste Holding Tank

[Panama Jack]

Hello to Peggy Hall and T J Furstenau and other Hunter Owners.

Regarding Aluminum Waste Holding Tanks

Peggy was correct!!!! .... back in August 2020, when she said that if you find corrosion on an aluminum waste tank that you can see, it will not be the first and there will be other areas that you cannot see ! Well, yesterday I had the marina service department help me remove my 25 gallon tank. We had to use the Sawzall to cut off the top vent bib and the side "feet", but it came out of the tight access in the aft cabin on my Legend 37.5 and guess what? The bottom was corroding like a sun of a b____!. It looked like it had a disease.... there was so much corrosion. We managed to get tank out of the aft cabin by turning it sideways to go thru the aft cabin door and up the companionway and the marina people took it away.

I am ordering a new plastic tank from Ronco, and new sanitary lines and 3/4 inch vent line.

Just wanted to thank you guys for your invaluable advice and to pass it on to others who are about to undertake this project, unless of course, I am the very last Hunter Owner in the country to finally remove their aluminum tank!

 

[Peggie Hall HeadMistress]

I'd make the vent line 1" or even 1.5" ...3/4 is only 1/8" larger than the "standard" 5/8".

I'll be glad to help you spec the best fittings locations if you want to send me a PM.

--Peggie

 

[Panama Jack]

What is your email Peggy. we will continue to communicate that way, please. And I can send you some drawings. and my cel number. I pretty much have the fitting locations in my mine.

 

[kappykaplan]

@Panama Jack , send Peggie a PM from this site.

 

[Panama Jack]

Not sure how to do that. What is "PM"? ...private message?

 

[kappykaplan]

Private message. Hover over Peggie's avatar.

 

[Ron20324]

I'd make the vent line 1" or even 1.5" ...3/4 is only 1/8" larger than the "standard" 5/8".

I'll be glad to help you spec the best fittings locations if you want to send me a PM.

--Peggie

Bear in in mind, when you double the inside diameter of the hose, you quadruple the circular area of the hose.
I used 1.25 dia I believe. (pi) times (R squared)=area. The biggest problem I had was making the 90 degree turn .

 

[Scott NIelsen]

I went through the same issue when I got my 37.5 7 years ago. i did a plastic tank and lost some holding capacity due to what was available at the time. then shortly after my fuel tank developed a leak. Long story short I learned that the original manufacturer for the tanks on Hunter sailboats will make you an exact replacement only out of thicker aluminum. It will take a few months for them to put in in their production line but is worth it for the form fit and function and exact replacement (more or less). I also did a modification on the fuel tank to better facilitate the installation of the new tank when I got it. The tank manufacturer is EZELL industries. If memory serves they are in Florida. Smartest thing I ever did on a tank replacement. Been happy for over seven years. Wish I had known about EZELL when I replaces the holding tank.

 

[Peggie Hall HeadMistress]

A good thing you didn't, 'cuz while metal is a good choice for a fuel tank and an ok choice for a water tank, but NOT for sewage holding 'cuz urine will turn a metal tank into a colander. Boat builders switched to PE holding tanks in the '90s.

--Peggie

 

[Panama Jack]

Peggie

Please email me.

 

[Panama Jack]

I went through the same issue when I got my 37.5 7 years ago. i did a plastic tank and lost some holding capacity due to what was available at the time. then shortly after my fuel tank developed a leak. Long story short I learned that the original manufacturer for the tanks on Hunter sailboats will make you an exact replacement only out of thicker aluminum. It will take a few months for them to put in in their production line but is worth it for the form fit and function and exact replacement (more or less). I also did a modification on the fuel tank to better facilitate the installation of the new tank when I got it. The tank manufacturer is EZELL industries. If memory serves they are in Florida. Smartest thing I ever did on a tank replacement. Been happy for over seven years. Wish I had known about EZELL when I replaces the holding tank.

Hey Scott

I went with the plastic tank from Ronco. It was wonderful. Just finished putting it in this past weekend. It took my wife and I and a marina service guy 6 hours. Also put in ALL NEW sanitary lines and vent lines. And yes, like you, I lost a little capacity.....from 24 gallons to 17 gallons....but since the tank was smaller, I could fit it in nicely and still have acces to the fittings and hose clamps, wherein before, it was too cramped and no accessibility. It is awesome tank and I can see in for inspection when to pump out without guessing, as in an aluminum tank .

 

[Peggie Hall HeadMistress]

 

[aaronshorb]

Having replaced the holding tank on my previous '92 Legend 35.5, I cannot emphasize strongly enough following Peggie's advice. I know that I did, and while in some aspects I may have created a bit more work for myself, I would do it again in a heartbeat. After replacing that tank, my holding capacity increased, holding smells all but disappeared, and pumpouts became a breeze.
Old tank had a bottom fitting for the drain, and I fitted a dip tube at the top. Prevented waste from sitting in a line/hose where it WILL eventually permeate.
Old tank had a single small vent line, I replace with 2 (port/starboard) 3/4" vent lines which allowed lots of air thru the tank. And as Peggie will tell you, more air is better, aerobic bacteria smell better than anaerobic.
Also, that larger vent line allowed me to run the rinse hose into the tank thru the vent - insures vent line is always clear (no clogs from spiders or overfilled tank), and also allowed me to run rinse in while pumping out. I'd start pumping and once it was going, run the rinse line in. Keep pump running until pump line shows it's coming out clear, and then shut of rinse line until empty.

T J

Hi TJ, You wouldn't happen to still have the specs for your Ronco tank would you??
I have a 1993 Legend 35.5 and am replacing my old tank now.
Any info, drawings, etc. you have to share would be greatly appreciated.

And after some time since your replacement....
Would you still suggest 2 larger vent lines?

AARON

 

[Peggie Hall HeadMistress]

I'm not a fan of two vents...larger vent line, yes, but aeration instead of a second vent. That doesn't have to be expensive...many boat owners are DIYing aerators using a bait box pump and some "perforated" hose run across the tank near the bottom.

-Peggie

 

[aaronshorb]

I'm not a fan of two vents...larger vent line, yes, but aeration instead of a second vent. That doesn't have to be expensive...many boat owners are DIYing aerators using a bait box pump and some "perforated" hose run across the tank near the bottom.

-Peggie

1. With all new lines and no odor issues. For a coastal cruiser frequently used boat with a 25 gallon tank... Would you bother to aerate the tank? I'm on the no side of the fence.

2. When I pump the toilet handle I hear air sucking through the upside down U bend vent behind the shower panel. Started after I replaced the head plus new vent (since I had the panel off anyway) but at the same time I replaced the holding tank with a little temporary one. Lots of conflicting posts out there. Is that really normal to hear?? Any guesses of what to check or what I can do to stop the noise?

 

[Peggie Hall HeadMistress]

No...it's not normal. You shouldn't hear anything from a vent line INSIDE the boat. Nor is a vented loop (I'm guessing that's what you mean by "upside down U") in a vent line.
Vent lines should be short--ideally 5-7'--straight as an arrow, and it shouldn't rise more sharply than 45 degrees because fresh air doesn't fall and the gasses in the tank can't rise, so they'll never meet to exchange the gasses for oxygen, which is essential to PREVENTING odor from being generated in the tank. This may require a longer-than ideal vent line with a VERY gentle bend in it, but only longer within reason. "Vent" thru-hulls are designed to keep sea water out of fuel and water tanks, they're NOT designed to let holding tanks breathe. Replacing it with an open bulkhead (aka "mushroom") fitting will not only help a lot, but also has the added advantage of allowing you to put a hose nozzle against to back flush the vent line on a regular basis to prevent vent blockages...anything that's trying to set up housekeeping in it will just be washed into the tank. Better yet, also enlarge the vent line and its thru-hull to 1". Finally, try never to let tank contents overflow or spill into the vent line...I know, this can happen due to heeling...when it does, back flush it as soon as you can.

--Peggie