Review of Marine Hardware

(Extract) If you want the best and can afford it, the Questus is easily the most Sophisticated.

Prior issue of Practical Sailor contained the first of three articles on radar antenna mounting choices. The first report was on mast mounts. This one is about what may be the fast-becoming-popular gimbaled backstay mounts.

In conjunction with this radar mount project, we made a small survey of Practical Sailor's neighbors at East Passage Yachting center and Ted Hood's Little Harbor in Portsmouth Rhode Island. An even 100 survey sheets were placed on sailboats that had radar. There were 39 replies. The number is not large, but it probably is a fair indicator of the way in which most boat owners handle the placement of radar antennas.

Of the 39 who replied, 22 have mast mounts. Eight carry the antenna on a pole. Only six are on backstays. There also were one mizzen mount, one arch and one custom frame. Mast mounts currently are the overwhelming choice. However when you specifically asked, "Do you wish you had chosen a different location or kind of mount or that it was gimbaled?" 5 of the 22 with fixed mast mounts (and one with a pole mount) said they wish they had gimbaled mounts. So instead of a mast-pole-backstay ratio of 22-8-6 bias, the score (counting the "wish I had" votes) would have been 17-7-12.

It's not just that mast-mounted radar antennas can be damaged by the flailing leech of a jib and that , even with a guard (off-the-shelf or custom made) the sail will develop a frayed edge.

The real allure of a gimbaled mount stems from a radar antenna's vertical beam width of 25 degrees, which means that if the boat is heeled more than about 15 degrees, signal loss sets in. How bad is the loss? As part of this series we'll be testing that, too.

In our survey, about a half dozen of the 39 who replied said they did not care about gimbaling because the boat is almost always under power and level when the radar is being used- such as when motoring into harbors, in fog or at night. The value of gimbaling seems to depend somewhat on whether the radar is used when sailing, especially as a collision avoidance instrument.

The hooker in gimbaling is how to prevent the device and the antenna from swinging freely. A sailboat is an engineering laboratory devoted to controlling movement. Anything loose is dangerous. Another detail that must not be overlooked is the loop in the electrical cable, to prevent breaking the cable's extremely fine wires through continual flexing.

There are on the market but three kinds of gimbaled antenna mounts. The three represent extraordinarily interesting entrepreneurial pursuits. At the heart of these mounts are devices that severely dampen movement as the boat heels. Two are hydraulic; the third uses mechanical friction.


THE QUESTUS

The gimbaled backstay mount was developed in 1989 by a Marblehead, Massachusetts sailor who, as is often the case, wanted something better than a fixed mast or pole mount on his 1974 Tartan 41

Allen DeSatnick has the means to do it right. He owns a successful company that makes surgical instruments and equipment including implants. A 54 year old engineer educated at the Massachusetts Institute of Technology, he knows and has high regard for precision work.

His Questus antenna mount, a very technical and finely made piece of equipment hit the market in 1990. Since then 3000 have been sold through Pompanette Inc, which owns Bomar, Hood Yacht Systems and several other marine companies.

The Questus is made to high standards, the quality is tightly controlled and in DeSatnick's words "the engineering is probably overkill."


The torque loads are transmitted through the hydraulic unit, down the pole to the deck. The cast base plate has a hole to carry the electrical cable through the deck. The hydraulic cylinder even has a thermal expansion chamber to compensate for temperature changes... for use in the tropics.

"The object", said DeSatnick "is to assure that the antenna platform always stays level. It may be slow in reacting to a fast roll, but there is no oscillation. And I expect it to work virtually forever, without fail".


The Questus comes in two models with mounting options and adjustments to fit any imaginable installation (including a mast or pole). Assembly, using the extensive installation manual, requires some meticulousness. For the record, the backstay options are: radome forward, pole forward of the stay, radome forward, pole aft of the stay, radome aft, pole forward, radome aft, pole aft; radome forward,stay inside the support tube; and radome aft, stay inside the tube.

Questus is the only maker with models which enclose the backstay, which requires some special lower-end tubing if you have a hydraulic backstay adjuster. It also is the heaviest of the three. The two-arm model (a version of which with other attachments is shown on the cover of this issue) weighs 18.2 pounds.