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Mast Winterizing

In our story "10 Ways Winter Can Wreak Havoc With Your Boat," we mentioned the importance of making sure drain holes are not plugged as part of your winterizing prep. Clogged drain holes in stanchion bases, mast bases/steps, and live wells have all resulted in claims. Reader Dennis Krizek of Gaithersburg, Maryland added one more item to that list: roller furling masts. As he explains on his website (, "The ... furling mast system [on the Beneteau 393] consists of a cylindrical tube for the furled mainsail, inside the mast extrusion. Essentially a mast within a mast. The sail slot for the mainsail to roll in/out, also allows water and debris to accumulate inside the mast. The drainage holes provided to allow this water to escape are minuscule and easily blocked by debris." When the water inside this cylinder froze, it expanded and tore the mast wall open between the boom and vang goosenecks. Other roller furling masts with similar construction could have the same problem. To be sure there is no water left in the extrusion, you may need to enlarge the drain holes. But consult with your spar manufacturer first to find out how to do so without compromising mast strength or integrity.

Understanding Class E AIS

Smart Chart AIS app

The Automated Identification System (AIS) is the newest tool for collision avoidance. An AIS transceiver combines an integral GPS with a VHF transmitter. It broadcasts the vessel's name, GPS course, speed, and, if enabled, data on its route and cargo on a VHF frequency (most units are dual frequency using VHF 87B and 88B). AIS transceivers also pick up that data from the vessels around them and calculate when they'll be at their closest point of approach (CPA) and how close they will pass; an alarm goes off if the vessels will pass within a certain preset distance. Most commercial vessels are required to use Class A transceivers, while recreational vessels may use the lower-power Class B transceivers. Class B "receive only" units don't transmit their own position but do receive AIS signals and allow you to determine if a risk of collision exists.

Several online websites track vessel movement using AIS signals picked up by shore-based receivers (such as VesselFinder and Marine Traffic), and these can be accessed on a tablet to provide you with information about the traffic around you. Accessing these websites from the boat can be an inexpensive alternative to buying a Class B "receive only" unit, but you must have a tablet aboard, be in range of a cell phone signal, and be able to access the Internet. As with the "receive only" units, no one will be able to see you because you are not transmitting your position, but you will be able to avoid the traffic around you in crowded areas with cell phone coverage.

Class E AIS, the newest addition to the AIS pantheon, builds on the tablet idea by using the cell phone network to provide your position information to others. The Smart Chart AIS app is downloaded to your smartphone or tablet, and it accesses the online tracking websites to provide you with information about the traffic around you. But it also transmits your position over the cell system, so others using Class E AIS on their phones will be able to see you. But, since the Class E signal is not a VHF signal, your boat will not appear on Class A and B AIS receivers on vessels around you. That ferry bearing down on you will not know you are there — unless the captain happens to be looking at the Smart Chart AIS app on his cell phone while driving, which wouldn't be such a good idea. Class E AIS is an accessible, affordable way to avoid collisions in crowded waterways, but users need to understand its limitations and not confuse it with Class A and B transceivers.

Gasoline Generators And Carbon Monoxide Hazard

Gasoline generators offer a handy source of additional energy for our power-hungry boats, but they also pose real dangers to the boat's occupants, most importantly the possibility of carbon monoxide (CO) poisoning. In addition to the two generators on the bow, the boat in the photo below had a third generator running on the stern. Member Dan Marchetto, who took the photo, wrote, "The foredeck generator power cables were brought in through the forward hatch (albeit stuffed with towels) making a perfect path for the noxious fumes to the sleeping quarters below." Just how dangerous is this?

Photo of gasoline generator on boat

A study published online in the Journal of Occupational and Environmental Hygiene and conducted by the National Institute for Occupational Safety and Health (NIOSH) looked at the dangers of using gasoline-powered generators without emissions controls on houseboats. The study found that these "uncontrolled" generators routinely emitted carbon monoxide in concentrations well above NIOSH's immediately dangerous to life or health (IDLH) value of 1,200 parts per million. "[For] houseboats that exhaust uncontrolled generator combustion gases beneath or near the rear deck, [the study] indicated that extremely hazardous carbon monoxide concentrations can accumulate in that area," said Captain Ronald M. Hall, the deputy branch chief in the Engineering and Physical Hazards Branch in the NIOSH Division of Applied Research and Technology in Cincinnati, Ohio. "These hazardous conditions were exacerbated when the drive engines were operating, placing employees who worked on or around the boats, as well as the boat operators, at risk."

Between 2004 and 2005, the two largest manufacturers of marine generators introduced fixed models with advanced engineering controls to lower CO emissions. These reduced CO concentrations by up to 99 percent in occupied areas on and around the boats. If you need a generator, Seaworthy recommends installing a low-emission fixed generator that is designed for marine use with the exhaust properly vented and installed by a professional. And make sure your boat has at least one working CO detector in its living spaces.

Light Hot Spots

This halogen lamp (photo at right) in the master stateroom of a large powerboat is within half an inch of the top of the closet door when the door is open. Gregory Group, a surveyor from Cleveland, Ohio, sent us these photos and said that with the door open, "in about one minute the wood door began to smoke." He measured the temperature under the light at over 400 degrees Fahrenheit. If you have incandescent or halogen lights on your boat that may be near flammable surfaces in some situations, switching them to LEDs will reduce the heat, and with it, the risk of fire. Group also noted that on many boats, "these lamps all look the same, but some are 110 V AC, some are 24 V DC, and others are 12 V DC, all unlabeled." Putting the wrong bulb in a fixture could also lead to a fire. If you have a variety of bulbs aboard, label them or store them in separate, labeled compartments to prevent confusion. 

— Published: October 2014

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