Warning: Long Post.
So just this past week we had another chance to implement the full capabilities of AIS send/receive and RADAR during a night return up the Chesapeake Bay. As darkness fell, rain and mist reduced visibility to 200 yards, the dodger windows misted over and we essentially sailed the last 35 miles on instruments.
My system is an integrated Navico/Simrad MFD with multifrequency RADAR and stand-alone AIS (dedicated antenna on the stern RADAR pole). Both returns overlay on my chartplotter so that I can see a confirmation of AIS with RADAR, real-time.
The Ches is a major commercial and military waterway with 900’ ships mixed with towed barges and tugs, especially at night when the assumption is that the rec boaters have gone home. Typically only the pros are on the water, BUT you have to account for fools who don’t make themselves visible or have the ability to see me.
At night the commercials like to travel in convoy and you can hear them talking on VHF. As we sailed instruments in 17kts of wind and choppy bay it was comforting to hear them pick out my boat and relay my location to others in confirmation. It was also comforting to see them show up on the chartplotter as an AIS target, with a name, COG, and SOG; then see them painted with a RADAR return. I see them at 10 miles or more on AIS, maybe reliable returns at 5 miles on RADAR.
Sailing on a starless and bible black night we were able to reliably and safely ID the commercials with a belt and suspenders combo of RADAR and AIS. We were also able to pick up AIS Cls B rec boats by their AIS long before we could see them on RADAR. Recreational boats made of fiberglass and wood provide poor RADAR returns; even if they have reflectors, even if they are massive floating mobo condos. Their return merges into a choppy sea, dispersed by mist and rain.
So this left us to find and ID the fools who might be out there with no AIS and no RADAR reflectivity. That became the challenge. Even the nav markers gave adequate RADAR returns, some broadcasting on AIS. Luckily the conditions were so deteriorated that any fool could see it was not a good night to be on the water without the right tools. So we had a safe, relatively relaxed and uneventful trip back to our slip. (now, if I could just get the crabbers to place their traps in the legal traps zones).
My point here is that these tools (AIS and RADAR) along with sophisticated MFD processors allowed us to safely navigate in all conditions. The new RADAR require very little training in their use, settings are automated with some controls for sea state, rain, and signal gain. But you have to know how to use them and learn to trust their information. That means using them during daylight and training yourself to interpret the data. You can’t go out, turn on your RADAR and navigate safely, you have to practice.
A few years ago we were returning to the Bay from the Atlantic. The Dismal swamp was burning, mixing smoke with sea smoke, it was a moonless night, commercials were anchored and lit outside the Bay Bridge and the lights of Virginia Beach made it impossible to pick out nav lights from the shore clutter. It looked like Times Square on bar-b-que night! The RADAR showed a faint return ahead but no AIS. A nearby Pilot boat showed on AIS. We slowed and trimmed down to gain full SA; the Pilot boat came on the VHF and hailed me by boat name (got that from my AIS B). He asked if I was aware of the warship in front of me. I noted that I was seeing a faint but not certain RADAR return but was hearing lots of helo and small boat noise. He said yes, it was a boomer headed home to Yorktown with an escort of Team Operators. No normal radio call by the Navy warning of Warship activity, total stealth. I suppose we might have been paid a visit by a SEAL if we got too close! Not sure.
I forget what I paid for my system, it was a lot. And I didn’t try to cobble it together on my own. I had a team of manufacturer-trained pros construct and test the system. Even then there were subtle mistakes that had to be shaken out and resolved. It was installed for days like Monday when these kind of navigation tools make it possible to go well beyond the normal protocols of safe boating.
along.
