Features September 1, 1998 Issue

Scanstrut A Best Buy in Radar Mounts For Masts

Other off-the-shelf mounts from Kato, Edson and Nautical Engineering each have strong points. The Furuno seems overly complicated and the D. Lily mount, while inexpensive, is heavy.

Radar (radio detection and ranging) is a marvel. It was invented and patented 75 years ago. But the British perfected it for use during World War II. The English claim radar won the war. George Patton thought he won it, with a minor assist from the United States’ industrial prowess. The Russians claim…

Radar needs no explanation other than what everybody who has one knows: It takes a bit of practice to get good with it.

The lingo is fierce—VRM/EBL, MARPA, CPA, SHM, RTM, DRM, TCPA, GRD, FTC, STC and don’t ask until you need to know.

But other than a tendency to spin off a bad case of acronymphobia, the only other hang-up when you elect to equip your boat with radar—which is basically a DSP coupled to a CRT or LCD—is where to hang the antenna, a.k.a. the scanner. If you have a big boat, the antenna can be a rotating arm (open array). Most sailboats use a radome, which is about the size of an old-fashioned wheel of cheese. Where to put it is often not a simple matter. Sometimes, a custom mount is the answer.

If you have a ketch or yawl, you’re singularly blessed. The antenna goes on the forward side of the mizzen mast. Perfect. Just mind the main topping lift.

However, those with sloops and cutters face some decisions. The radar antenna can go on the front side of the mainmast, on the backstay or on a pole mounted on the stern. Referring to the latter, some manufacturers call the stern mount a “radar mast” or “tower.” However, for clarity, we’ll call it a pole.

A few place it—along with a lot of other electronic frippery—on the increasingly popular arches, which makes mounting the radar antenna no challenge at all. On sailboats, “radar arches” generally are so ugly, we’d like at this time to postpone talking about them. We do have here at Practical Sailor some sense of aesthetics.

Wherever the radome goes, it should be high enough to avoid sweeping the crew. It’s claimed that it is especially not good to get it close up in the eyes. Further, the higher it’s mounted the further it can see, because it’s a line-of-sight instrument, but too high and it can’t see objects under its angled beam, in what is known as the “shadow sector.”

(For those who fret, the subject of radio radiation is covered in a new Bulletin #65 published by the Federal Communications Commission’s Office of Engineering and Technology. It is entitled “Evaluating Compliance with FCC-Specified Guidelines for Human Exposure to Radio-Frequency Radiation.” If you want to avoid a heavy dose of Federalese, you may, generally speaking, regard as equally harmful a small radar antenna and the microwave in your kitchen.)

If you want radar to help you navigate narrow, buoy-marked channels, the radar should be fairly low, a foot or two above standing-up head level.

If you want a radar to detect ships and land at fairly long range (maybe a dozen miles or more), higher is better, which means up on the mast. High or low? Somewhere between 10' and 20'. It’s something you alone can consider. Bear in mind that mast mounting your radar places weight and windage aloft; it also will make climbing the mast more difficult.

If you intend to use your radar while under sail, you can consider a gimbaled (athwartship only) or adjustable-level mount. Radars lose some of their punch when the boat is heeled. Because most radar antennas have a vertical beam width of 25°, a boat heeled more than about 15 degrees is pinging airplanes or submarines. It’s acute for targets on either beam, less so for those directly ahead or astern (unless you’re pitching).

To sort out the complications, Practical Sailor will deal in three separate articles with the off-the-shelf choices in mast, backstay and pole mounts, and attempt a summary at the end of the third one. The summary will include costs, which can range from a couple of hundred dollars to $3,500 for a fancy, multi-purpose pole mount. This review will be about mast mounts.

Most mast mounts are made of aluminum (cast or welded-up plate), usually white powder-coated. A few are fabricated with stainless tubing, which is more expensive.

Whatever the material, the mounts call for more holes in your poor mast. To attach the radome, there are some mounts in which you’re expected to drill holes in the mounting plate, but with either the radar set or the mount, you’ll come by a template to assist you. For others, you specify what make and model of antenna you intend to attach to the mount, and it comes with holes pre-drilled or slotted.

A very nice development of the last several years is that, without any industry discussion, there seems to be a tendency to make the four holes 6" on centers. That’s good, admirable standardization, particularly because Raytheon recently changed the hole centers on its new Pathfinder models—without warning mount makers.

Here’s the line-up, which pits the international powers, Edson (United States) and Scanstrut (England), against all the little guys.

Edson
Edson is a 139-year-old New England company that tends to dominate any product market it enters, mostly because it makes good on its claim that everything it makes is quality. Fairly big (25 employees), for a primarily marine company, Edson is most widely known for pumps and steering systems, especially pedestals and pods.

Edson’s Hank Keene said that for radar, Edson likes pole mounts because it places the radome at the optimum height, which he said is 10 to 14 feet above the water level.

However, because of the popularity of mast mounts, the company last year introduced a mast mount, which comes in three sizes.

Edson’s new mast mount is a well-done, one-piece, high-quality aluminum casting, simple and strong. Edson has its own foundry. The middle-sized mount (for 17" to 20" radomes) weighs about 3 lbs. The entire mount, including the feet, has an extremely glossy baked-on urethane coating.

The mount’s top surface has four slots for stainless steel bolts to attach most any radome. The two vertical support sections are fastened with stainless bolts to four articulated aluminum “feet” affixed on the mast with three rivets each. The rivets are supplied by Edson.

“The rivets make this mount special,” said Keene. “They’re solid, no hole in the middle, serrated and each will take 500 pounds.”

Edson’s mast mounts are priced, list and discount, at $258/$199, $272/$239 and $306/$269.

Edson has in the works a circular guard rail made of thin aluminum tubing, which will be powder-coated. It probably will be similar to the one offered by Nautical Engineering (see below) and may be available by the time this is published.

PYI
The other biggie is Scanstrut, an English manufacturer whose mounts are imported by PYI, along with Max-Prop, Whitlock steering and PSS shaft seals.

The British maker provides for Edson very vigorous competition in radar mounts and pedestal-pod assemblies.

Scanstrut has strong ties to Autohelm, the British instrument maker, and with the huge (110,000 employees) Raytheon Corporation. In fact, a Scanstrut mount is an accessory for Raytheon and Autohelm radars.

Besides two new mounts for Raytheon’s Pathfinder® series ($250 list for the 18"; $350 for the 24"), Scanstrut’s eight established models cover virtually any radar antenna.

PYI’s Scanstrut manager, Robert Bright, said, “Scanstrut’s new Raytheon mounts are the cleanest and lightest. No adapter plates are needed, which keeps the cost down.”

The small, one-piece Scanstrut weighs just over 2 pounds. Even with the stainless guard (a separate item), the weight is about 3-1/2 lbs.

Scanstrut’s entire line, from the small one-piece mounts to the clever two-piece models (see photo) reflects excellent design and fabrication. All use small articulated, cast-aluminum feet that, like the new Edson, can be riveted to a mast.

A compliment was paid to Scanstrut by several other small manufacturers who said, in identical language, “Everybody copies from Scanstrut.”

The Scanstrut mounts for radomes up to 18" (not open array antennas) range in discounted price from $180 to about $200.

In addition to its excellent mounts, Scanstrut offers through PYI a unique, two-piece cable conduit. Fasten the flat piece to the mast and snap on the cover with the cable tucked inside. Available in two sizes (1/2" and 3/4"), the PVC, at about $4 a foot, is not cheap, but it’s handy stuff, on the mast, inside, anywhere there are cables or wires to run.

Stainless by Kato
One of the few makers of stainless steel mast mounts, Kato Marine is a small Annapolis company more widely known for stainless davits and outboard hoists.

The 10-year-old company makes two sizes of its mast mount—for small radomes (16", 18" and 20") and one large one for 24" domes. The small model (6 lbs.) is made of 3/4" stainless tube; the large one (12 pounds) is 1" tube.

The small model lists for $365, the large one for $445. Defender discounts them to $340 and $400, respectively.

Kato mounts must be considered semi-custom. A buyer supplies, in response to a questionnaire, the make and model radar, and mast dimensions or type (Kato has on file information about hundreds of production boats and all major spar makers.)

What you get for a considerable chunk of money is an amazingly strong, nicely welded and polished assembly (most of its eight employees are welders) that fits like a glove. The arms that attach to the mast have only a 3/16" “give.”

Keith Olver, a partner in Kato and a longtime mast expert, said he likes to see the unit attached with stainless machine screws. He concedes, however, that high-quality aluminum rivets might be stronger. When using any stainless fastener, the usual precautions must be taken to avoid dissimilar metal corrosion.

Finally, what makes the Kato mounts especially attractive is that, by design, they are both a mount and a guard rail (see photo).

Olver said that the guard circle limits sail chafe. Far more importantly, he said, the guard ring protects the radar from being beaten to death when the sail’s leech flogs it.

“Damage to the radome itself is the biggest problem with mast mounts,” he said. “In any kind of breeze, the sail’s leech actually hammers it, every time you tack.”

Nautical Engineering
Nautical Engineering is a tiny Michigan company that offers a small line of mast and pole mounts for sailboats and powerboats.

The 24-year-old company, considered in the industry to be a high-quality innovator, makes a small line of boat hardware, including the AnchorLok, a patented pair of clips to hang a Danforth-type anchor on the bow pulpit.

For its radar mounts, NE uses aircraft-grade aluminum, anodized, powder-coated or covered with baked vinyl, or stainless steel.

“Whatever metal or treatment seems best, we use,” said Bob Ahern, NE’s owner.

NE’s most popular mast mount, which comes in two sizes to fit most radomes and masts, has a patented mounting system which Ahern said was designed to provide structural strength and stability.

“It’s real virtue,” said Ahern, “is that it wraps around the mast and fastens on opposite sides, rather than mainly toward the front.”

The smaller version weighs 7 lbs. and is $275; the larger model, which weighs 8 lbs., lists for $348.

Cognizant of the chafe problem, NE offers for the mounts a cleverly designed guard made of aluminum tubing with a powder coating. Extremely light, the big one (26" diameter) weighs but 2 lbs. and lists for $155; the smaller (20" diameter) weighs only 1 lb. and lists for $125. They’re easy to mount and, being very light and very effective, make good sense.

D. Lilly’s Line
There used to be a Donald Lilly (he started the Long Island company in 1968), but he’s long gone, replaced by a couple of family partners who keep alive Lilly’s name. This small company (five employees) is known mostly as a principal makers of mounts for marine radio antennas, but also makes a fairly full line of sailboat and powerboat radar mounts.

What’s unusual about Lilly’s mast mounts is that (1) they are white powder-coated stainless steel, and (2) they are very modestly priced. They are heavier than those made of aluminum.

John Jennings, Lilly’s son-in-law, said, “We just believe that stainless is stronger and will last forever.”

He said they are powder-coated because that’s what customers want.

“We’ve never had a request for a polished stainless version,” he said. “We use a Long Island powder-coating company that really knows its business.”

Lilly’s model 4000, which weighs 11 lbs., is a universal mast mount that accepts most makes of radar antennas. It lists for $258; West discounts it to $197. It fits masts from 4" to 8" wide.

The small model 2000, for both powerboats and small sailboats, can be mounted vertically, horizontally or at an angle desired. It has 90° angle feet that can be made to fit any angle. Not shown in the photos, it lists for $176; West sells it for $140.

Furuno
For its small radar sets, Furuno offers a mast mount apparently made for Furuno by some company called Aumont. Defender sells it for $240. The mount works; we’ve seen the mount on a number of boats.

However, it’s a contraption by any accounting, the Aumont mount is a seven-piece nightmare that comes with a dozen stainless steel machine screws and lots of washers. Took about 15 minutes to do the assemble loosely, as recommended.

It’s adjustable to fit most small- to medium-sized masts. The instructions say to fasten the assembly to the mast with stainless rivets, two sets of four—which is not easy. Tightening it all up, in place, must be a knuckle-buster.

It’s only real virtue, in our view, is that it’s light—4 lbs.

We didn’t check to see who Aumont is, mostly because there are lots of better-designed mounts that are easier to install and that wouldn’t worry you about whether all those machine screws are tight.

The Bottom Line
There are other makers of mast mounts, including two gimbaled mast mounts. They are the widely known Questus, handled by Hood Yacht Systems, and the Waltz RLS (radar leveling system) handled by Performance Marine. Both are seen more often on stern poles, as well as backstay versions. They will be discussed in a later article. There also are custom fabricators that will make up a mast mount in virtually any configuration. Among these is an expert marine stainless shop, Tops-In-Quality, 314 E. Huron, Marysville, MI 48040; 810/364-7150.

Looking at off-the-shelf mast mounts, the stainless Kato, which is both a mount and a guard, is expensive and heavy. The Lilly powder-coated stainless models are heavy, but they’re also inexpensive, especially the small “fits anywhere” model 2000.

For medium to large sailboats, the Nautical Engineering line, made of aluminum, very strong and only a bit more money, seems preferable to Lilly. All Kato, and most Lilly and Nautical Engineering models have a slight liability in that if the radome must come down for service, it must be removed from the mount, which remains on the mast.

By contrast, Edson and Scanstrut used “footed” mounts that, by removing four bolts, permit lowering the radome and mount together. Edson and Scanstrut also stand out because of their modest weight, always a plus when adding gear up high.

Edson, a top choice in most anything it makes, sets prices that might be considered premium. If you always choose top quality, you’ll go for Edson.

However, Scanstrut has, in our view, the best combination of low weight, quality and cost. A Scanstrut mount is an all-around Best Buy.


Contacts- D. Lilly & Company, 25 Linden Place, Port Jefferson, Long Island, NY 11776; 516/473-7779. Edson, 146 Duchaine, New Bedford, MA 02745-1292; 508/995-9711. Furuno, USA, 271 Harbor Way, South San Francisco, CA 94080; 415/873-9393. Kato Marine, 7416 Edgewood, Annapolis, MD 210403; 410/269-1218. Nautical Engineering, 700 Doheny, Northville, MI 48167; 248/349-1034. Scanstrut, PYI, Box 536, Edmonds, WA 98020; 425/670-8915.

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