PS Advisor December 2013 Issue

Pondering a DIY Diesel Tank

Do your homework before making a composite tank.

I have often referred to (former PS Editor) Dan Spurr’s book, “Spurr’s Guide to Upgrading Your Cruising Sailboat,” and I was going to follow Spurr’s advice and build a plywood/glass tank to add auxiliary diesel tankage to my Morgan 382. But the Gougeon Brothers / West System website ( makes it sound contrary to standards and potentially damaging to insurance coverage.

Terry Thatcher,
Morgan 382
Portland, Ore.

It’s likely that West System does not publicly endorse homemade wood/epoxy fuel tanks because of obvious liability reasons, given that it involves do-it-yourself construction and combustible liquids. That being said, we (including Dan Spurr) think that a boat owner can certainly build a safe plywood/epoxy diesel fuel tank. Note that we specify “diesel” here. Gasoline systems—which have higher volatility and combustibility—are much more heavily regulated than diesel systems, and thanks to the introduction of ethanol fuels, related federal regs are an ever-moving target as lobbyists continue to push for higher ethanol limits.

Before planning out your build-a-tank project, first check with your boat-insurance provider to determine whether a composite tank would affect your premiums. If your insurer gives you the green light, the next step is to thoroughly research relevant government (local, state, and federal) regulations and industry building and safety standards.

The U.S. Coast Guard has no published regulations for diesel fuel systems on recreational boats, and the Safety Standards for Backyard Boatbuilders cover only gasoline tanks. However, be sure to pick up a copy of the American Boat and Yacht Council (ABYC) standard for fuel systems, H-33. Although ABYC H-33 oddly focuses only on metal tanks, we consider it required reading for anyone building a diesel tank in any material. It covers venting, material thickness, safety testing (for fire resistance and strength), etc., and according to the standard, non-metallic materials are acceptable, as long as all other standard requirements are met. Also check out the International Organization for Standardization (ISO) standards 10088 and 21487, which specify requirements for permanently installed fuel systems on boats up to 72 feet long.

Once you have a handle on all the regs and standards, talk with West System about which epoxy they recommend. Be sure to use a diesel-resistant inner-tank coating—whether it’s gelcoat or a specialized epoxy paint. Not all epoxy-laminating resins are immune to diesel, and over the long run, resin residue can gum up high- pressure injection pumps. The key to a durable composite diesel tank is a thick, well-cured epoxy coating.

If you find a composite tank isn’t for you, consider a custom aluminum tank. Aluminum is easy to work with, fabrication is reasonably priced, and it is PS’s preferred diesel tank material. See the May 2007 article on diesel tank replacement to find out why.

Head Cleaners

After reading your article, “Two Marine Toilets go Head to Head” (PS, January 2008), I bought a Raritan PHII. Raritan recommends using its bio-enzymatic toilet cleaner. However, PS recently advised against using cleaners. Should I forego using Raritan’s cleaner?

Ned Walsh
1984 Beneteau Idylle 11.5

Our concerns regarding head cleaners were related to some household chemical cleaners (like Lysol) and winter-storage formulas that can harm toilet joker valves over the long term (PS, July 2013). We reported on head and holding tank treatments in the February 2012 and December 2012 issues, and found that when it comes to cleaning agents, chemicals that augment aerobic bioactivity are the best way to reduce head and holding tank odors. Regular use of these products and a long-handle scrub brush can work miracles with head odors. The December 2012 test included Raritan’s bio-enzymatic cleaners, KO (Kills Odors) and CP (Clean Potties). While the top pick in that test was the Bactank T3 powder, both Raritan liquid treatments earned testers’ Recommendation, so, you’d do well to use those.

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