Plumbing

Practical Sailor recently tested an updated version of the SeaLand 20 HTS-VRT holding tank reviewed in our November 2011 test, which found the Trionic SP-2020 super premium holding tank to be the Best Choice. For this test followup, SeaLand sent us a tank with the inlet and outlet fittings firmly installed and sealed with pipe sealant, as the maker recommends. (Aftermarket tanks are typically shipped with fittings separate.) The re-test found the revised SeaLand to be leak free, but the Trionic is less expensive and showed less deflection.

In the December 2011 article, “Maintaining Stainless Steel,” you mention that there are hose-clamp makers that get the stainless-steel combination right, but never shared who those manufacturers might be. I’d love to know who’s your pick!

To create a real-world test, we assembled a series of miniature holding tanks containing sanitary waste generously supplied by a 20-pound, 5-foot pet iguana named Ziggy. This was supplemented with other sanitary waste as needed. Seawater flush was used because saltwater is known to contribute to odor.

The effectiveness of activated carbon comes both from surface activity (a result of activation by partial combustion of coal or woody products) and the vast pore structure formed during this partial combustion. Anything that clogs the pores will dramatically reduce carbon life, potentially ruining it within minutes.

Although none of the test tanks or the test boat’s holding tank accumulated solids sufficient to restrict pump-out, we observed significant differences. While vent filters did not increase tank solids beyond what is normal in a poorly ventilated and un-treated tank, some of the subject tanks did better than others.

For a real-world test, we created a series of small but real-world holding tanks containing real sanitary waste. The sanitary waste was supplied by a 20-pound iguana. Ziggy already poops in a tray of water and we know this mixture to be plenty foul. This was supplemented with additional sanitary waste during the start-up period each spring. Seawater flush was used, as the odor problems associated with seawater are known to be more severe, the result of bacteria-reducing sulfate into more odorous sulfide chemicals. Tank tests were supplemented with field testing aboard a test boat on the Chesapeake Bay.

Before beginning a series of tests, we always involve the manufacturers. They have a wealth of information they are happy to share, in the interest of reducing problems with their products. In general, their advice forms a consensus.

In our 2002 holding tank test, SeaLand emerged as the winner. The material of choice for holding tanks continues to be rotationally molded linear polyethylene, which is light in weight, doesn’t corrode, allows for seamless tank construction, is relatively inexpensive, and won’t allow odors to permeate. This new test compares a pre-2009 model SeaLand tank to a new holding tank from Trionic Corp. The holding tank test looked at the tanks’ construction materials, price, size, valves, inlets, outlets, leaks, inspection ports, vent size, warranty, and performance-based panel deflection. Preventing threaded fittings from leaking was the hardest part of the test.

Practical Sailor evaluated washdown pumps capable of performing high-pressure cleanup chores on boats ranging in size from a weekender to a mid-size cruiser. We looked at eight pumps from four manufacturers: the C-60 Deck Wash Kit from Groco Marine; two pumps from Jabsco / ITT; two from Shurflo; and three from Johnson Pumps. With gallons-per-minute ratings ranging from 3.5 to 7 GPM, the pumps were evaluated on their free-flow and restricted outputs, outflow distance and pressure, power draw, price, warranty, design, and construction quality.

Most washdown pumps are plumbed to draw directly from the water you’re sailing in (fresh or salt), in which case, the amount of water available for use is unlimited. The only problem with using a raw-water system in salt water is the residue left behind—although a salty boat is often better than a nasty one. A second option is feeding the system from the boat’s freshwater tank. This will typically limit the amount of water you can use, but it does offer the advantage of reducing the effects of corrosion on metals via freshwater washdowns.