DIY: Removing Sand in Water Tanks

When Executive Editor Charlie Doane found sand in his water tanks, he assumed it was the result of extensive tropical cruising. But guess what— the culprit was chlorinated water.
Author:
Updated:
Original:
SandPhoto.1

While sailing my Tanton 39 Lunacy south to the Caribbean a few seasons ago my crew and I noticed there was some sandy grit in the fresh water running out the taps when the boat was bouncing around in rough weather. The operative theory at the time was that this crud was just what it appeared to be: sand. We reckoned at some point in the boat's long cruising career, which included a westabout circumnavigation, some sandy water had come aboard in some remote tropical port. The sand had then settled to the bottom of the tank, where it sat until it got stirred up by the boat’s motion.

The following summer, after moving the boat north again, I decided to open up all three water tanks and try to remove the sand. Getting into the water tanks was easy. The inspection plates are under the settees and nav seat in the main saloon, with access hatches right over them.

SandPhoto.2

I was a bit mystified by what I found inside. The walls of the aluminum tanks were bright and clean, but there was indeed a build-up of crud at the bottom of each V-shaped tank--a bit of brown schmutz, plus an accumulation of what appeared to be sand. But was it sand??? Though the tank walls looked good, I wondered if this "sand" was the result of some sort of corrosion.

Cleaning out the tanks was easy. They are well designed, with the lowest point in each tank right under its inspection plate, so flushing out the channel under the baffles and then vacuuming out all the crud was quick work. I hoped this would solve the problem, but a little over a year later, when I opened the tanks again, I found more sand inside.

On doing some research I learned that my sand is the result of the tank interiors coming in contact with chlorinated water. I have never treated the water on Lunacy with chlorine, as many cruisers do, because I have always assumed that chlorine cannot be good for aluminum. But many public water supplies these days are treated with chlorine, and this water, if left for prolonged periods in aluminum tanks, will cause deposits of aluminum oxide to form.

To solve this problem, I’ve put together a filter kit that cost all of $50 with bits and pieces I found at Home Depot. A stock home water-filter housing and some charcoal filters for removing chlorine, plus some adapters that allow me to plumb in a dock hose, should be all I need to keep that damn sand out of my tanks in the future.

SandPhoto.3

If you have aluminum water tanks on your boat, you’d do well to put together such a rig yourself and run all the water you’re taking aboard through it before it hits the tanks. If you need to treat the water on your boat to keep things from growing in it, you should use peroxide rather than chlorine. Peroxide has a longer retention time and will not attack aluminum.

Related

T31A4577

Cruising the Eagle Class 53

Sailing at 19 knots in 15 knots of breeze is not an earth-shattering experience anymore. I was thinking about that on a perfect late summer day in Narragansett Bay while we were slicing along on the most technologically advanced cruising catamaran I’ve ever seen—the Eagle Class ...read more

1.-Exterior-old-port-600x

Know-how: Replacing Portlights

Years ago when my wife and I were running sailboats in the Caribbean we once had a guest who, when we're at anchor, would occasionally look out the big saloon ports at the, ahem, “scenery.” (We spent a lot of time in the French islands back then.) More recently, if this same ...read more

Nathan-Bates-San-Diego,-CA

SAIL Reader's Photographs

Are you out there sailing, cruising and living the sailing life? If so, we’d love to see it. Send your sailing photos to sailmail@sailmagazine.com And don’t forget to sign up for our free eNewsletter. We saw this rainbow on the west coast of Fatu Hiva in the Marquesas Islands, ...read more

10-002

Ask Sail: Analog or Digital

Q: I am redoing my voltage distribution panel and can’t decide between a needle movement voltmeter or a digital illuminated voltmeter to monitor my house and starting battery voltages. Which way would be best? — J. Henshaw, Tampa FL GORDON WEST REPLIES I would say do both types ...read more

Ultime-maxi-trimaran-2048x

Video: The Power of an Ultime Tri

. If there was ever any doubt as to the speed potential for the eye-popping Ultime maxi-trimaran class, the first 24 hours of the Brest Atlantiques race have surely put such doubts to rest. The drone footage above of Franck Cammas and Charles Caudrelier’s Gitana Edmond de ...read more

Brest-Atlantiques-2048x

Video: Brest Atlantiques Fleet on its Way

The four monster trimarans taking part in the 14,000-mile Brest Atlantiques race, from Brest, France, to Brazil and then Cape Town and back, found themselves battling brutal conditions under deeply reefed sails from the word go. The event in many ways represents the pinnacle ...read more

TOTW_PromoSite

SAIL's Tip of the Week

Presented by Vetus-Maxwell. Got a tip? Send it to sailmail@sailmagazine.com Fine-tuning a Sure-fire Solution  It’s fun to look back over a summer’s cruising by way of the track my chartplotter has recorded. Where the track really comes into its own, though, is piloting out of ...read more