Holding Tank Condition Question

[DH]

I have an aluminum holding tank that I suspect is approximately 24 years old, the age of my boat. I think it is around nine gallons. There appears some discoloration and some flaking on one lower corner. Does that mean that it is developing a hole, or is this just something aluminum does. The only leakage I found is a slight amount I just discovered from the pump out connection. None at this time from the discolored, flaky looking corner, but the leakage I did find may have dribbled onto the corner of the tank where the discoloration is.

I intend to replace all hoses and valves. It probably would be best to put in a new tank, but they cost in the neighborhood of two fifty to three hundred dollars, and I would like to not spend that if I don't have to.

Thanks,

David

[Allure2sail]

Hi:
The Aluminum holding tank on my 1987 27/2 had corroded threw (porous) when I bought her four years ago. I replaced it with a twelve gallon rectangular shaped plastic tank two years ago and it was on of the better upgrades I've done. It still mounts on the starboard side on a shelf platform I built and is as high and as outboard as I could get it. I still have enough room to get into the Lazaret (it is tight, I'm 5'10" 220lbs) with me facing forward or aft. I can take pictures of the setup and measure the tank L x W x H if you would like. The holding tank is still in the parts boat I have if you want it (just pay the shipping and crating materials). I just can't imagine it is in any better shape than the one I got ride of or the one that is leaking in your boat. I would assume the PH level of what's in there eventually eats threw it (makes for a smelly boat).
Good luck
Bruce

[DH]

Bruce,

I would very much like to see your set up. Thank you,

David

[bmiller]

The plastic tanks are much less expensive and available in a wide variety of sizes. I got mine from http://www.tank-depot.com/browse.aspx?id=1163, don't remember exactly which one though.

Here's a couple photos of my set up:

This shows the plumbing runs, the lowest white hose goes from the head into the top of the holding tank, the little black one next to it is inlet water, the hose into the bottom of the y-valve is from the bottom of the tank, the top right of the y-valve goes to the macerator then overboard via thru hull, the top left of the y-valve goes to deck pump out.


This next photo shows the side of the tank, sorry best one right now. Note the fresh water lines have been replaced and rerouted since this photo was taken.. I built a little shelf for it and made ss brackets to hold it in place, the orange padding is split fire hose.

If you want more photos I can get them in a couple days.  Good Luck and keep us informed.

Also important, You will need a fitting relocate kit and the inspection port if I remember.

[Allure2sail]

Hi:
I did take the holding tank out of the parts boat and the bottom is porous as well, sorry. As a matter of fact the fitting on the bottom stern face of tank broke of when I went to pull the hose off of it. I would go plastic for a replacement as well. I will take picture of my 12 gallon plastic setup this weekend when I uncover the boat for the springtime prep.
Thanks & good luck
Bruce

[cdreamIII]

David,  I am halfway thru the same process.  I purchased a 14 gal tank from the tank depot along with fitting relocation & pump-out kits http://www.tank-depot.com/productdetails.aspx?part=RH-B265  This tank is 14 1/2 x 14 1/4 x 17 1/2 tall & just fits thru the cockpit locker.  In hind site, I would probably go with a slightly smaller tank because running the hoses are going to be a bit tight during installation (a project for this season providing I can find the time).  For now a porta-potty works well.

Bill E

[DH]

Will this work? Instead of building a shelf for the tank, could you take a piece of marine plywood a bit larger than the back of your plastic holding tank so that fasteners could be attached to the bulkhead in the same locations as the old aluminum tank? Use 5200 adhesive to the back of the holding tank, and then attach it to the plywood. Then attach the plywood with fasteners to the bulkhead, and secure the tank with a metal band around it as shown in the above post by Bruce Miller.

David

[Tim Gardner]

David,

Nothing sticks to polyethylene.  For the same reason as they are chemical resistant: PE has no free electrons for the glue molecules to share.  To accomplish your goal, strap the tank to the adapter plywood in both horizontal and vertical directions. 

I'd hate to see the mess of a dropped tank that was glued on. - tg