Cleanout access for aluminum freshwater tank.

Oct 2, 2008
1,424
Island Packet 31 Brunswick, Ga
I want a cleanout access port for our aluminum freshwater tank because even after multiple cleanings we continue to have a lot of white crystals in our plumbing. These things result in clogging up the filters. In addition we get a foul odor if we leave the boat for more than a few days. I would like to cut a hole in the aluminum tank and install an access port. It seems to be a straightforward job but wanted to see what tools and techniques people here would recommend.
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Gunni

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Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
A gasketed screw port with O-ring is necessary to make sure that your tank vent continues to be the location where over-fills discharge.
 
Oct 24, 2010
2,405
Hunter 30 Everett, WA
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I suspect someone did that with our water tank. In our case there was no doubler inside. I highly recommend installing one to stiffen up the top of the tank around the flange.

Here is a pic before I took it apart to stop the leak between the flange and the tank.

Ken
 
Mar 26, 2011
3,399
Corsair F-24 MK I Deale, MD
I'd be more concerned about the cause of the white crystals (the chlorine in the tap water is eating your tank). Water chemistry may also be a factor, since the bad smell is almost certainly from sulfates being reduced.

Cleaning is still an excellent idea; if there is an accumulation, it needs to be removed, since it will harbor bacteria where the chlorine cannot reach them.
 
Sep 28, 2008
922
Canadian Sailcraft CS27 Victoria B.C.
.....for our aluminum freshwater tank because even after multiple cleanings we continue to have a lot of white crystals in our plumbing. These things result in clogging up the filters. In addition we get a foul odor if we leave the boat for more than a few days....
You always will. Uncoated aluminum is a bad choice for a water tank for this reason.
 
Oct 2, 2008
1,424
Island Packet 31 Brunswick, Ga
Excellent idea on the doubler, thanks!
And thanks also for the link to the fuel tank inspection port.
As always, this forum is the best one out there!
 
Jul 7, 2004
8,402
Hunter 30T Cheney, KS
I'd like to do the same thing to my poly tank. Do any access covers come with doublers or will I need to fab something?
 
Oct 24, 2010
2,405
Hunter 30 Everett, WA
I'd like to do the same thing to my poly tank. Do any access covers come with doublers or will I need to fab something?
I don't know but I still need to fab one for our boat. Even with all those bolts it won't hold without.

Ken
 
Feb 14, 2014
7,399
Hunter 430 Waveland, MS
I'd be more concerned about the cause of the white crystals (the chlorine in the tap water is eating your tank). Water chemistry may also be a factor, since the bad smell is almost certainly from sulfates being reduced.

Cleaning is still an excellent idea; if there is an accumulation, it needs to be removed, since it will harbor bacteria where the chlorine cannot reach them.
This probably the cause, but don't be in hurry to clean the crystals. Bacteria needs food, AlCl3 crystals no, sulphates & nitrates yes.

I just replied to a similar problem on Crystals in Tank, perhaps I was long winded, but you may be chasing a rabbit by cutting your tank.
http://forums.sailboatowners.com/in...tank-of-hunter-legend-40.175552/#post-1251030

If you have sulphates and chlorine, I would suggest the carbon active filter to filter ALL water BEFORE it gets in you nearly "fresh" water tank. Obviously the filter cartridge longevity depends on the load to be filtered, but they claim 15,000 gallon per cartridge. Low chemicals in tank, lower maintenance.
Jim...