PS Advisor June 2014 Issue

Vertical LPG Storage Tanks

The 411 on vertical versus horizontal propane tanks.

My 1979 Tayana Vancouver 42 came with two horizontal propane tanks and one vertical propane tank (all three 20-pound aluminum) when I bought the boat in 2007. I contacted Worthington Industries and learned that “horizontal” LPG tanks are those with the additional brackets attached for horizontal installation and must be used horizontally; those without brackets are vertical tanks and must be kept vertical, which is the norm from everything I’ve read. I’m a bit surprised that not more is published about horizontal LPG tanks.

I kept the two horizontals and sold the vertical as there is no practical place to store a vertical tank on the boat. My aft-cockpit V42 has a fiberglassed compartment in the forward end of the starboard lazarette. The compartment’s width is just a hair too small for both 20-pound horizontal tanks to fit side by side (making the valve controls easy to get to) and, therefore, they have to go in at an angle instead of perpendicular to the boat centerline. Each tank has provision for a four-bolt tie-down, but practically speaking, this is impossible to accomplish due to the limited access.

Mike Hirko

Destiny, Tayana Vancouver 42

Gig Harbor, Wash.

In order to be compliant with the American Boat and Yacht Council (ABYC) standards regarding onboard propane storage (A-1), an onboard propane system can use only vertically oriented tank. From what we can surmise, using horizontal LPG tanks in U.S. boats is rare, but Europeans and South Africans, on the other hand, use both vertical and horizontal.

Most portable LPG tanks sold in the U.S. are called “DOT” tanks because they are built to conform to design and usage regulations established by the federal Department of Transportation. Both horizontally and vertically mounted portable DOT tanks are available, but note that they are not interchangeable. They must be stored, filled, and used only in the specified horizontal or vertical mounting position.

LPG tanks designed for horizontal use have welded “feet” or mounts and are specifically plumbed for horizontal use; the internal valve has a bent tube, allowing withdrawal from the vapor space only. Using a vertical tank in a horizontal position—particularly on a cold day, before the liquid in the hose can vaporize—may allow liquid LPG to flow to the burner, giving you the equivalent of a poor-man’s flame thrower when trying to make that morning cup of coffee. This could also occur on warmer days, because of the boat’s hobby-horsing.

One symptom of mounting a vertical tank horizontally is that the flame at the burner will have minuscule “flickering” (caused by liquid LPG droplets igniting in the flame). Also, the hose typically will be cold and sweating (covered in condensation). The emergency relief valve (internal/external at tank) can also freeze in the open position. If this happens, any heat that causes high pressure in the tank (strong sunlight on a hot day for example) may cause it to vent liquid LPG, possibly the entire contents of the tank.

Seeking Mooring Info

The last time I moored in the inner basin of Cuttyhunk Harbor, Mass., I noticed that the harbormaster had modified the mooring ball design. There is now a plastic pipe protruding from the ball, which holds the mooring pendant about four feet above the water. I would like to modify my own mooring system to take advantage of this design. Do you have any information how the system is constructed? I am planning to use a 10-foot section of 2-inch CPVC pipe with four feet above the ball and the remaining six feet under the water acting as a stabilizer. I am particularly concerned about the CPVC pipe chafing the upper thimble and eye-splice section of the pendant.

Gerry Bliss

Via email

According to Cuttyhunk Harbormaster Capt. George Isabel, those moorings were designed and built by Bruce’s Splicing and Rigging Co. out of New Bedford, Mass. For more information on the moorings, contact them at or 508/992-9519.

Comments (1)

I thought the "harbormaster" in Cuttyhunk was called a Wharfinger? I thought that was quaint old English.

wharfinger |ˈ(h)worfinjər|
an owner or keeper of a wharf.
ORIGIN Middle English : from wharfage + -er 1 .

Posted by: George D | July 3, 2014 8:39 AM    Report this comment

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