Radar Offshore: The Unsung Crew
Radar is no longer an exotic navigation device
Radar pinpoints buoys, identifies landfalls, spots squalls and fronts, alerts you to the approach of a ship, and provides range and bearing in crossing situations
Not long ago, radar was considered an exotic and unusual navigation device to have on the average offshore boat. I can remember making landfall with my parents in pea-soup fog with only the seats of our pants to get us home. When we thought we were close to a critical buoy, the engine, if running, was shut down. Everyone would be as quiet as possible to try to pick out the sound of the bell or gong and then try to determine from which direction it was coming. Or, when sitting at anchor, watching a column of small boats, like a string of ducklings, following the ferry or large yacht with radar. Initially, radars were large, drew huge amounts of power, and the antennas were gigantic. The pictures were difficult to read, and gazing into the snow of the display, wishful thinking often played a larger role than real expertise with the equipment. Times have changed.
About 10 years ago, when asked what the most important navigational devices to have on board were, my reply might not included radar. And if it did, it would not have been at the top of the priority list. Loran C or satnav would have come first, and an autopilot would even have edged radar out. However, with the huge strides made in the electronics field, and with much lower prices than ever before, radar - integrated with positioning devices - is an obvious choice for blue water sailors.
Versatile radar
Inshore: The most obvious application is when entering or leaving port in reduced visibility, or finding the buoy or waypoint when visibility is down. Landmasses are easily identified on radar, especially when we know where the starting point is, and heading out through a breakwater is like heading down the interstate. When visibility is reduced, radar is also a useful defensive gadget, enabling us to keep out of the way of other traffic. Large metal objects like buoys show up very well, and while fiberglass is a poor reflector, even the round mast and rigging on a sailboat will give a return that can be recognized from sea clutter or extraneous returns. With a little practice (in good visibility), one can become very adept at recognizing what is a real target and what is not - even to distinguish between fishing buoys, navigational buoys, and small boats.
On a recent double-handed return from Nova Scotia, we had extremely thick fog and 22 knots apparent on a close reach, which made for a great sail, but with hearts in mouths as we were logging almost 10 knots. We knew the area was teeming with fishing buoys, and every so often one would flash by almost close enough to touch. Fortunately, they were of the lightweight variety, and only the ends of the buoy strings were of the heavier reflector type. The radar picked up these ends clearly enough, but it was tricky guiding the busy helmsman through the minefield. At one point, the Portland-to-Yarmouth ferry approached and looked huge on the screen as it went by at a relative speed of 25 knots! Anticipating a long and tense night, we were relieved when the moon rose shortly after sunset and the fog dissipated completely. The prospect of one of us glued to the radar while the other steered through the night was not one I was not looking forward to.
Offshore: Using radar to navigate buoy to buoy, to avoid other vessels in a busy situation, or to enter harbors is the primary application for sailors. However, radar has extremely useful offshore applications, well away from obstructions and navigational aids. Even in clear conditions, I generally keep the radar burning at night (on standby) to clearly monitor any targets that come over the horizon. After dark, our reactions and judgment are not as good as they are in daylight, and radar will take the guesswork out of an offshore crossing situation. Ranges can be immediately determined, and crossing angles can be anticipated. Many times, I have seen range lights and thought that the ship was safely on the horizon, only to find myself looking up at those distant lights a few moments later. A radar plot would have relieved the situation and alerted me to a close crossing situation and high closing speed.
Weather: On ocean passages, squalls are frequent companions, particularly at night, accompanied by heavy downpours. The heavy rain will show up as a large, fuzzy target on radar. If sailing at good speed, you can alter course slightly to avoid cells of rain and the gusty local winds ahead of the squall.
On a recent passage from New England to Grenada, we were just north of Bermuda, hove-to in about 45 knots of southerly. While we could have slugged it out, we chose to heave-to and await a frontal passage forecast within 8 to 10 hours. We continued to stand our watches hove-to, which consisted of monitoring the radar, taking a peek around every few minutes, and cleaning the galley and refrigerator when too bored. At about 0300, an image that looked like a solid landmass entered the radar display from the northwest and rapidly moved across the 12-mile screen radius. It was the anticipated front, and we had plenty of time to prepare for the 180° wind shift. For more on using radar as an onboard meteorological tool, see Michael Carr's article, "Radar Detection of Squalls and Fronts" on page 28.
The extra hand: Another feature (perhaps a tad less seamanlike) of radar is it's potential as an extra crew member. A few years back we were sailing south in November from Newport, R.I. After a brisk start, we motored along in a complete vacuum for the next seven days. Our daily routine was generally cleaning in the morning, a noon stop for a swim, checking the engine while shut down, lunch, and then a movie. Of course, the radar was set with a guard-ring at 12 miles to alert us of any traffic entering our plot of ocean, and the watch would stick his head out of the companionway every 15 minutes or so. In this way, we could enjoy our feature film without being disturbed by pesky shipping. Simply said, radar has become an affordable, indispensable tool that can make our onboard lives easier, less stressful, and more enjoyable.
Installation wrinkles
Installing radar on a small sailing vessel is commonly done in two distinct ways:
(1) put the antenna as high on the mainmast as possible,
(2) fabricate a post or arch on the stern to carry the antenna. Clearly, radar operates in a line-of-sight manner, so the higher the antenna, the farther away a target on the horizon appears, or the farther over the curve of the earth one can see. Assuming that your target (bridge of a ship or elevated radar reflector) is at least 50 feet above the surface of the water, if your antenna is mounted on a stern-post at 15 feet above the surface, the potential range of your radar unit will be about 121/2 miles. If the antenna is, say, 35 feet above the surface, the target will be visible at about 15 miles.
Mast-mounted: Clearly, a greater range can be achieved with a higher elevation. However, the range ratings of the various manufacturers are determined in a favorable setting, and optimal performances are measured. In the real world, we find that a 16-mile radar might pick up a landmass at that range, but there is no hope of picking up a small target at that distance. If the gain is cranked up to intensify distant targets, chances are that the increase will cause a lot of clutter close-in, which will obscure the picture. The point is that, in practice, one rarely operates outside of the 12-mile range, so the potential gains by mounting the antenna high on the mainmast are not as great as they seem.
Chafe and abuse by halyards and the leech of the genoa also need to be considered. One final thought on a mainmast installation: The wire run between the antenna and display will require a terminal block or connector, which can be disconnected to allow the mast to be removed. Radar cables can have up to 24 or more conductors, some of which are very small coax. Making these delicate connections can be a nightmare, and the connections are susceptible to water damage. The diameter of the factory plugs is sufficiently large to make their use impractical when running the coax inside the mast.
Stern-post mounted: A dedicated stern-post is the way to go in our opinion. Factory cables and plugs can be used, and the wire run is generally shorter than up the mast, so one may get away without cable extensions. This makes the entire installation "plug & play" for basic operation without any questionable hardwire connections. Those with ketches already have an ideal radar pole in the cockpit.
Cockpit display: There is a trend among sailors to have all information right at the helm, including the radar screen. While it seems a nice idea, in practice the entire crew ought to be able to see the information, not just the helmsman. We also find that, at night, radar screens can be extremely bright (particularly the CRT displays) and ruin one's night vision. Conversely, during the day in bright sunlight, the CRTs get badly washed out. The LCD types need to be viewed head-on, not from the side. The issue of a true waterproof display is a huge consideration for cockpit mounting. While most new units can take an occasional dollop of water, I am skeptical that plugs and switches can stand true submergence very frequently.
For these reasons, I feel the best place for the radar display is in the nav-station below, with perhaps a repeater in a waterproof mount in the cockpit. This will require communication between the navigator and the watchkeeper, but you can be assured that the main unit will stay dry and keep functioning.
Radar types/features
CRT or LCD: Radars available today are remarkable for their clarity and resolution at short ranges - that is, less than 20 miles. Take a look at the masts of any commercial shipping you pass, and I'll bet there is a small yacht-type antenna mounted just alongside the powerful 48- or 72-mile antenna. The products available today fall into two basic display categories: LCD (liquid-crystal display) and CRT (cathode-ray tube). The less expensive and "waterproof" models tend to be LCD, which can also be viewed a bit easier in direct sunlight. The CRT displays are the traditional types, which tend to give better resolution and pictures. Current LCD models are vastly superior to the original units produced several years ago, so it would seem that the LCD technology might catch up to, and even surpass, the older CRT. However, for the time-being, we feel the CRT display gives a better picture.
Output power: This is the determining factor of range. The small yacht-type units we are discussing here are of 2, 4 or 6 kilowatts. Very simply, the more power, the greater the range. A slight increase in range can be achieved by using an open-array antenna rather than a dome type, the most common on sailboats. The hazard with the open-array is that a halyard or other line can be caught up in the sweep of the antenna and damage it or its motor. For this reason, we will limit our discussion to the dome-antenna models.
Bells & whistles: Today's state-of-the-art radars are packed full of bells and whistles unheard of just a few years ago. Virtually all are capable of displaying navigation data (if supplied from an external source) on the radar screen. Zoom-in is standard, as is moving your position from the center of the screen (to make more screen available ahead of you), which is referred to as "off-centering." Controls on the screen almost always consist of tuning, gain, rain clutter and sea clutter. Tuning matches the "receive" portion of the set to best accept the reflected signals. Gain is essentially a sensitivity-setting that ought to be kept as low as possible to keep the screen from becoming snowy, but high enough to show weak targets.
Sea and rain clutter adjusts are just that - filters to clean up the screen when weather is poor and seas are up. I find that IR (interference rejection) is useful to keep the display clear while having the gain at a higher level. Auto-tune, which automatically adjusts gain and tune (but can be manually overridden), is the norm, and guard zones with audible alarm features are standard on all.
The ever popular and practical "lollipop" is a favorite feature that places a circle around a waypoint or target, keeping track of which target is indeed your waypoint in a "go to" image. The lollipop feature does require external position information, as well as compass or heading sentences, typically from your autopilot's fluxgate compass. Calculated heading information from your GPS or Loran will work, but will wander a bit compared to direct compass readings. Numeric range and bearing to the waypoint can also be displayed. A clever and useful option now available enables identifying and tracking moving targets (other vessels) relative to your own course. This is an invaluable tool for collision-avoidance.
Finally, using the radar CRT or LCD to display electronic charts is a built-in feature on nearly all radars now. A separate card or disk-reader can be linked with the radar, and the operator can toggle between charting and radar display. To my knowledge, no one has yet come up with an economically feasible way to superimpose an electronic chart onto a radar image, but this feature cannot be far away.
A radar selection
The accompanying table breaks the radar selection into three categories, which are defined by price, type of display and size of display. The small LCD units are best suited for 35- to 40-foot boats; the small CRT units (7") are suitable for boats up to 45 or 50 feet; and the larger 10" CRTs are best suited to vessels over 50 feet. Of course, much more powerful equipment is available for larger pocketbooks, but keep in mind that great elevation is required to see out 30 or 40 miles, so the smaller unit may meet the task at hand. The LCD displays are more likely to be waterproof (to a degree anyway), and so are better suited for an exposed mounting. Size of display is the major choice with the CRT, radars with a larger screen being easier to see. The physical bulk of the display must be reckoned with in the navigation area; a suitable spot must be found where it can be easily viewed.
LCDs
Furuno, Raytheon, Autohelm, Si-Tex and JRC (Japan Radio Co., Ltd.) all make models of LCD radars with varying power and display sizes. The antennas are quite light, ranging from 9 to 16 lbs., and displays are 6" to 8". The simplest and least expensive units are the Furuno 1621, the Raytheon RL-9 and the JRC Radar 1000. All will give reasonable images on a waterproof display, but don't expect much performance over six or eight miles. The prices are reasonable; in fact, the JRC is advertised at under $1,000. A relative newcomer to the game, JRC has been making equipment for Raytheon for many years, and is now marketing their own line.
Take a small step up and enter the higher-end LCDs that provide higher power (range), larger displays and, of course, a higher price tag. These radars put out up to 4kw and are priced in the range of the small CRT units. However, the pictures are quite good and they have waterproof displays - but how waterproof are the rear connectors?
Furuno has cleverly packaged up their 821 display without an antenna, and offers it as an on-deck repeater for other Furuno radars. Both Raytheon and Autohelm have identical units that feature 7" screens, and all the bells and whistles previously discussed. Nicely engineered and packaged, the LCD type radars are attractively priced, and will certainly show you what is out there ahead of you.
CRTs (small)
Furuno, Raytheon, JRC, Koden, and Si-Tex all manufacture dependable small CRT radars. CRT-type displays have been the standard in radar for many years. While not faring well in direct sunlight, the resolution is a step ahead of the LCDs. All of the reviewed manufacturers offer high-quality 7" displays with every feature we have touched upon. The Furuno 1721, Raytheon 10XX , and JRC Radar 3000 all have 7" displays matched to antennas, which put out 2kw. The same equipment can be bumped up to 4kw to increase range, but features remain the same. Antennas are all lightweight, and the display units, which have a considerable depth dimension (not unlike a television), can usually be sited comfortably in the nav-station. As with the LCD displays, the built-in navigational screens provide repeaters for all navigation functions. The JRC does not support any charting features, however.
While all of these radars have "standby" modes (to conserve power and eliminate warm-up time), Raytheon has a very neat feature that allows the operator to program the system to "wake up" at certain intervals and take a sample of what is in view. For instance, with a guard-zone set up, one can tell the radar to take 20 seconds worth of sampling every five minutes, which should lend a degree of safety when operating short-handed or singlehanding. By doing so, power consumption will cut by about 50%. Raytheon features a pop-up screen for charting. This enables you to view both the radar and electronic chart at the same time, and then toggle for the larger image - just like the new televisions that allow viewing two channels at once.
CRTs (large)
Furuno, Raytheon, JRC, Si-Tex and Koden all have high-output radars that provide high resolution. If you have a larger boat, or just want better imaging, all of these manufacturers make a product that can easily match your pocketbook. They are not much different than the smaller units, except in power output (range) and size of display. In practice, a large display is desirable and, once used, hard to drop down from. Particularly at short ranges, the higher power of these radars allows for a very crisp image to be displayed from even weak targets. Higher power consumption is inherent with higher power output, but the rewards are real. By using standby modes or, in Raytheon's case, programs to scan samples at appropriate intervals, you will keep power at a manageable level. And when you want the big picture, you have the means at your fingertips.
The BWS choice
At present, Furuno and Raytheon are perhaps the most readily recognized producers of radars today. Certainly, Raytheon, with a very strong military market, has a long history with radar. Furuno captured a huge market share in the past 20 years, and deservedly. One commercial pilot of our acquaintance stated that Furuno is the choice in his trade for bridge radar, and a small yacht-size model is always mounted for "in-close" work.
Koden has been a producer of commercial radar for many years, and one may assume that they now collaborate with Si-Tex to complement their products with the small sets from Si-Tex. As already stated, JRC has been in the hardware side for many years in conjunction with Raytheon, and has now struck out on its own. Autohelm, with its single LCD model, also has a marketing and product history with Raytheon.
NEMA interfacing: These days, you will want to take advantage of the display computations that modern radar can make, and interfacing with other manufacturers' products will likely be needed. NEMA sentencing has become an established standard, but quirks still occur. All reviewed manufacturers offer position-finding instrumentation and electronic charting, but only Raytheon and Autohelm offer a full line of sailing instruments as well.
The ability of linked instruments to "talk" with each other is not as simple as it may seem. Raytheon and Autohelm use their "SeaTalk" messaging, which works well with their own kind. However, we have experienced sentencing problems when trying to integrate with "foreign" equipment, or equipment manufactured by another manufacturer. The problems are not insurmountable, but some tweaking is likely required. Experience shows that Si-Tex is forgiving when talking with other brands of equipment. Autopilots also need to be considered into the mix to provide heading information.
Track record & worldwide recognition: Frankly, all the reviewed radars are fine instruments that will faithfully serve for a long time. However, in our opinion, Furuno and Raytheon have to be the choice for track record, name recognition and availability of parts and service around the world.
Price: The JRC Radar 1000 has an unbeatable price and works well for short-range work.
Repeatability: If you want repeatability, Furuno and the dedicated model 811 repeater is a logical choice.
Standby programming: If you want the standby"wake-up" programming, Raytheon would be the choice.
Compatibility: If you want a single manufacturers' name on all electronic equipment to assure compatibility, Autohelm makes sense because of its SeaTalk messaging, and because its complete lines of sailing instrumentation has a common language.
The other radars all work acceptably, and one might want to consider their own user-preferences (e.g. comfortable keystrokes) when selecting a unit. Similarly, the larger CRT radars all have slightly different operating controls, so you may want to practice on each one to see which feels right to you. Whatever name you choose, as we enter the 21st century, your radar and associated electronics will, when properly used, keep you out of trouble and help you enjoy your voyaging to the max.
