Watchkeeping

How does the singlehander keep watch hour after hour, day after day anyway? Here is the watchkeeping system I use aboard Sparrow.

Coastal

When on a continental shelf, I typically do not sleep at all. If I’m heading down a coast and staying on the shelf, naps are non-existent to short and the AIS, radar, and active radar reflector stay on.

Offshore

When off the continental shelf and weather or traffic is not a factor, the 24 hour cycle I’ve used when singlehanding is to use a simple kitchen timer and set it to an hour. I lie down to rest either in a bunk or the cockpit, depending upon conditions. When it goes off I get up and check the AIS, radar, and scan the horizon with 7×50 ED glass binoculars. Typically I will make any adjustments to course or sail trim or conduct sail changes. If nothing is going on, I’ll hit the bunk again and set the timer for another hour. I will do this roughly 4 times through the night, and 2 or 3 during the day.

There are exceptions to this routine. When within 100 miles of land in an area where there may be small craft with poor radar return without AIS, sleep time will need to be curtailed based on speed and visibility (see Scenario 3 below). In these cases, it is important for the skipper to be better rested prior to closing in on land so as not to become overly fatigued.

Tools

Tools for this watchkeeping routine include binoculars with ED glass, AIS with CPA/TCPA alarms, radar with Watchman mode and alarm, and an active radar reflector with alarm when pinged by radar. The AIS and radar reflector is on continuously, while the radar is continuous (on the continental shelf) or the Watchman is set to come on for 2 minutes every 10 to 20 minutes off the shelf.

The binoculars I chose are the Fujinon 7×50 FMTRC. They are heavy, but I just dig the rubber coating. They have a dedicated mount on the inside of the companionway.

The AIS transponder is the Veper Watchmate 850. It has low power draw especially with a display, important for a device that will stay on continuously.  This model has been out for years and proven reliable.

My radar choice may seem odd with the new technologies out today. The radar is the recently released Furuno 1815 with an old style, high power consumption magnetron antenna. Furuno has high reliability and the best watchkeeping & alarm system in my view. The Watchman mode keeps the power consumption down to Broadband/solid-state levels, especially as the Furuno does not need an MFD. It is a 4kw unit, which should reach out 40 miles or so.

I’ve long been dissatisfied with passive radar reflectors. Ships I contact rarely see me first, so I decided to invest in a different solution. The active radar reflector is the Echomax XS, with the antenna mounted above the 2nd spreader, well above the radar so Sparrow’s radar should not interfere. I’ve not tested this unit yet, so after some experience I will post a review of the unit.

Effectiveness

To analyze the effectiveness of this system, lets do some math on some realistic worst case direct oncoming vessel scenarios. Scenario 1 is an oncoming commercial ship. If we assume Sparrow is going 10 knots, a little above hull speed, and an oncoming ship is going 20 knots, then the closing speed is 30 knots. Sparrow’s AIS antenna is 80 feet above the water line, and if the ship’s antenna is a conservative 150 feet above waterline, then the line of sight distance for the AIS signal is 30 miles. If we set the AIS CPA alarm at 10 miles, then the alarm will sound when the distance closes 20 miles, or 40 minutes later. This also gives me 20 minutes to deal with the closing situation. At 10 miles, the AIS CPA alarm should pick up any vessel with an active AIS transponders.

Scenario 2 is an oncoming fishing vessel, but either has no AIS or has turned it off. Sparrow is again doing 10 knots, and lets say the fishing vessel is running at 12 knots. Let’s also assume the radar is in Watchguard mode, set to alarm at 10 miles, and comes on every 20 minutes. Let’s assume I’m sleeping and the Watchguard just missed the fishing boat at 11 nm. In 20 minutes when the radar comes on again, the fishing boat is 3.7 miles away and the alarm sounds. This distance provides 10 minutes to handle the closing situation, still plenty of time.

Scenario 3 is an oncoming small craft with no AIS and an extremely poor radar return such as a fiberglass sailing vessel with no reflector or small, low powerboat. An unlikely occurrence to meet such a vessel off the continental shelf, a vessel like this is likely to be moving at a slower speed, so let’s say 6 knots for a closing speed of 16 knots. In this case, the only way to be alerted to the vessel is through human eyes (ears are quite unlikely). Maximum horizon visibility in the best of conditions is 10 miles. If the vessel is not visible at 11 miles before I hit the bunk, this provides 40 minutes of time before a collision. So with this scenario, sleep time should be limited to 35 minutes, maximum with perfect visibility, considerably shorter with poorer visibility. Similarly, slower speeds would allow longer sleep times. While theoretically possible, after 20,000 miles offshore, I have yet to encounter a Scenario 3 at sea. Scenario 3 occurs often enough along the coast that visual watchkeeping must be vigilant.

Being Seen

The flip side of course, is being seen so that other vessels know you are in the vicinity:

• Radar reflector – EchoMax XS that returns a radar signal when it is painted by one. On continuously, the Echomax was chosen as passive radar reflectors have demonstrated poor radar returns.
• AIS transponder – Vesper 850 with connections to a cockpit display, radar and wifi. This will be on continuously.
• Lighting –  masthead tri-color, running, steaming, deck lights and a spot light. Offshore, the masthead tri-color will be on duck to dawn.
• Horn – manually operated air.

Conclusion

Ships and fishing vessel collision scenarios appear well covered with this system. The Scenario 3 small craft scenario off the continental shelf requires judgement taking into account visibility, vessel speed, and likelihood of encountering a vessel offshore with no AIS, no radar and small radar return. For example near Hawaii, this risk should be taken seriously. In the Southern Ocean much less so.