PS Advisor 07/15/99


Holding Tanks and Hoses
My brother-in-law and I are planning to install a holding tank in our 1970 Morgan 28. Ive tried to research the best option, from hard copper pipes to stainless steel tanks to PVC hose and inflatable holding tanks. In his Offshore Log, Nick Nicholson only mentioned PVC, but referred to on-going PS tests.

We primarily sail in the Great South Bay, but every year sail east and visit Shelter Island, Block Island, and Newport, Rhode Island. With the spread of No Discharge harbors, please advise.

Roger Daisley
via e-mail

Wed use polyethylene for the holding tank. If they have a size that fits, SeaLands tanks are thicker-walled than the others. And SeaLands Odor Safe PVC hose is the best of the white sanitation hoses for containing odors. We have tested it but not reported the results yet. The only thing better is rigid PVC pipe, bought from a home supply store. No odors can get through it, but routing rigid PVC is more difficult than semi-flexible sanitation hose. We replumbed our test boat with as much rigid PVC as possible and it made a huge difference. We also have a SeaLand discharge pump for emptying the tank outside the 3-mile limit, which is what we usually do. Its nice not to have to depend on pump-out facilities, which is what we do, of course, when needing a pump-out in the harbor.

Which Prop?
We own a 1972 Newport 41. A Newport 41 is a West Coast-built version of a C&C 41 of the same vintage.

We would like to maximize speed under power and maintain the boats excellent sailing characteristics. It appears that a 3-blade feathering prop would be the best solution to our propeller needs. However, we have no idea which prop would be best for us. Do you have a recommendation?

Paul Stemler
Corona Del Mar, California

We published results of tests conducted at the Massachusetts Institute of Technology in the October 1, 1993 and January 1, 1995 issues. The latter is available from our publishers Back Issues Department by calling 800/424-7887 or sending an e-mail to:

A feathering prop has less drag than a fixed prop, but a bit more than a folding prop. A feathering prop such as the Max-Prop, however, has better performance in reverse, which may be important if you keep your boat in a marina. The Max-Props efficiency in forward isn’t quite as good as a fixed or folding prop because its blades are flat; the solution is to apply more throttle…if the horses are available. Nonetheless, the Max-Prop is an excellent, all-around choice, albeit an expensive one.

We keep our test boat on a mooring and so can get by with a folding prop, which does just fine motoring. But when we have to bring the boat into a marina, we go very, very slowly! The makers of the Martec folding prop, however, insist that a boat with a folding prop can stop quickly enough, and that the secret is in applying lots of revs to the engine. We do, and its still nerve-wracking.

Fixed props are the least expensive and are probably the most efficient for motoring. But the drag, which varies by boat but probably costs .3 to .8 knot on the average, is a serious drawback for one who likes to sail as fast as possible.

Yet another choice is the self-pitching Autoprop, an unusual design that automatically changes pitch to match loads. It, too, feathers under sail. Cost is about the same as a Max-Prop.

As boat owners are won't to say, its another case of trading off one attribute for another.

Darrell Nicholson, editor of Practical Sailor, grew up boating on Miami’s Biscayne Bay on everything from prams to Morgan ketches. Two years out of Emory University, after a brief stint as a sportswriter, he set out from Miami aboard a 60-year-old wooden William Atkin ketch named Tosca. For 10 years, he and writer-photographer Theresa Gibbons explored the Caribbean, crossed the Pacific, and cruised Southeast Asia aboard Tosca, working along the way as journalists and documenting their adventures for various travel and sailing publications, including Cruising World, Sail, Sailing, Cruising Helmsman, and Sailing World. Upon his return to land life, Darrell became the associate editor, then senior editor at Cruising World magazine, where he worked for five years. Before taking on the editor’s position at Practical Sailor, Darrell was the editor of Offshore magazine, a boating-lifestyle magazine serving the New England area. Darrell has won multiple awards from Boating Writer’s International, including the Monk Farnham award for editorial excellence. He holds a U.S. Coast Guard 100-ton Master license and has worked as a harbor pilot and skippered a variety of commercial charter boats.


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