Directly from the article

"Conclusions

Even with single-plies, seawater degradation was slow. This highlights the need to never pump overboard near shore; if you must, use a macerator and not just a diaphragm pump.

The clear loser was facial tissue. Its biodegradability performances left little doubt that it would remain intact underwater for months and cause clogs.

Testers were reasonably happy with all of the single-plies we tested, with the Scott Rapid Dissolve leading the pack. However, rapid dissolving is not the only thing that counts, and Scott Extra Soft’s greater user-friendliness make it a winning substitute for a more cushy two-ply. Single plies are typically flimsier than double plies, but this can be compensated for by using slightly more single-ply sheets per wad, which is still usually less paper (by weight) than a double ply. More importantly, the single ply is less likely to clog.

Except for the marine toilet papers, two-plies are an unacceptable risk of head clogs. They were much slower to break down, most critically during the initial stir when they would be passing through the joker valve. If they fail to break up during pumping, you can be sure they will be trouble at the pump-out."

Yes it is good information and the conclusion paragraph tells the tail. "never pump overboard near shore" "two plies are an unacceptable risk"

This test was also preformed with a manual head. Hence the word pumps in the body of the text. Very few boats in charter still have manual heads. The electric heads while convenient are much more prone to clogging.


My post and those observations are based on thirty years of personal boating and maintaining a fleet of 20 or so charter boats for the better part of the last ten years.


Jay