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 wont to say, its another case of trading off one attribute for another.

Practical Sailor has been independently testing and reporting on marine products for serious sailors for more than 45 years. Supported entirely by subscribers, Practical Sailor accepts no advertising or any form of compensation from manufacturers whose products we test. Testing is carried out by a team of experts from a wide range of fields including marine electronics, marine safety, marine surveying, sailboat rigging, sailmaking, engineering, ocean sailing, sailboat racing, and sailboat construction and design. This diversity of expertise allows us to carry out in-depth, objective evaluation of virtually every product available to serious sailors. Practical Sailor is edited by Darrell Nicholson, a long-time liveaboard sailor and trans-Pacific cruiser with more than three decades of experience as a marine writer, photographer, boat captain, and product tester. 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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