Electrical

Letters to Practical Sailor from our readers. September 2010's topics include barnacles, teak finish, knots for a bosun chair and LEDs.

According to multiple reports, most AC electrical fires occur at the boats shorepower inlet. To address this and other shortcomings of the standard twist-type boatside connection, SmartPlug Systems developed a new AC shorepower system that the company hopes will become the new marine standard. Loose and corroded connections are most often the culprits when overheating occurs. Corrosion typically results when moisture gets in at the plug-inlet connection, while arcing-which in turn leads to pitting, scorching, and heat build-up-is partially due to the shape and small contact area of the connector pins.

When we last dropped in on the realm of interior lighting (Practical Sailor January 2009), we looked at light emitting diode (LED) replacements for incandescent bulbs in a traditional bulkhead-mounted reading light. The test revealed some significant advances in LED technology, and those advances continue today at a lightning pace. Responding to the call for energy efficiency, LED makers are packing more and more luminosity output into smaller and smaller packages. As our reading light test showed, LED technology has developed to a point where finding LED "bulbs" that can provide enough illumination for reading is no longer an issue. Results from that comparison prompted PS to consider whether another key light on our boat-the galley light-could soon go the way of the incandescent reading light. Unlike reading lights, a galley light needs to cast a very wide beam angle to illuminate a large area, something LEDs alone are not very good at.

Practical Sailor looked at three Wi-Fi antennas suggested by readers: the Bad Boy Xtreme from Bitstorm, Rogue Waves Wave Wi-Fi from GeoSat Solutions, and The Wirie, developed by cruising couple Mark Kilty and Liesbet Collaert. All three are marketed specifically to boaters, and they represent the two principal types of devices that users will find: USB-type units that plug into computer or laptop USB ports and Power over Ethernet (PoE) bridges that network via your computers Ethernet port to provide a pathway to the Internet.

The Practical Sailor February 2010 issue launched our test of marine inverter-chargers with a look at the inverter capabilities of units from six manufacturers. This report compares the battery charger functions of the inverter-chargers from Charles Industries, Magnum Energy, Mastervolt, ProMariner, Tripp Lite, and Xantrex. Our recommendations differ based on an owners needs. One unit is excellent for sailboat owners with larger AGM or gel-cell batteries who plan to expand their systems down the road, while another is better suited for those who have no expansion plans, offering a combination of lower price, features, and sophistication.

To decide which marine inverter-charger best meets your onboard power demands, first consider how it will used, how and where it will be mounted and what is required to fit with your electrical system. After testing multiple marine inverter-chargers, Practical Sailor offers this report on the units’ inverter capabilities and a follow-up review will report on the units’ charger functions. There are two classes of marine DC inverters: true sine wave (TSW) and modified sine wave (MSW). Each uses a different method to produce AC voltage. Practical Sailor evaluated modified sine wave units from Charles Industries, Magnum Energy, ProMariner, and Tripp Lite, and true sine wave units from Magnum, Mastervolt, ProMariner, and Xantrex.

As we did with the Torqeedo electric outboard and Minn Kota trolling motor in past tests, Practical Sailor put the Solid Nav Traveler to work in sea trials on a Cape Dory Typhoon to determine whether it was a viable replacement for a small boats gas-powered outboard. The four-horsepower Traveler electric motor is marketed by Solid Nav and manufactured by Suzhou Parsun Power Machine Co., Chinas largest outboard exporter. Using a brushless 48-volt DC motor made by Mars Electrical Co. of Milwaukee, Wis., the Traveler combines a familiar drive train and an innovative solid magnet electric motor. At first glance, it looks like a small conventional outboard. Available in both long-shaft (20 inches) and short-shaft (15 inches) models, the Traveler is a gasoline outboard alternative best suited for a pocket cruiser (like a Cal 25) or similarly sized weekend cruiser where electric propulsion is desired. However, its required battery entourage limits its portability and affordability, and charging needs limit its practical use on smaller boats.

I am looking at antenna mounting options for my 2.2-kilowatt radar. I like the idea of keeping the antenna out of the foretriangle and its sail and rigging, but am a little concerned about crew exposure by mounting the antenna aft on a pole or lower on the backstay. The manufacturer (Furuno) mentions nothing about exposure hazards in its installation manual. Does a hazard exist in this configuration?

With the increased demand to have all the electrically powered comforts of home onboard, it should come as no surprise to boaters that the majority of AC-related electrical fires involve overheated shore-power plugs and receptacles. Prime Technology, aims to change all that with the introduction of its Shore Power Inlet Protector (ShIP for short), a monitoring and alarm device that automatically disconnects AC shore power when excessive heat is detected at the power inlet connector. We reviewed the ShIP 110 designed for use with a 110-volt, 30-amp system. The company also offers a similar unit (the ShIP 220) for use with 220-volt, 50-amp service. Charred plugs and receptacles are the result of resistance build-up (due to loose or corroded connections), which generates heat and the potential for fire, a problem especially prevalent among vessels that continually run high energy loads such as water heaters and air-conditioning units. In addition to monitoring the temperature of your vessels shore-power inlet plug and its wiring, the ShIP system automatically disconnects AC shore power when an unsafe temperature is detected, providing visual and audible alarms. (The audible alarm shuts down after five minutes to avoid prolonged disturbance to surrounding boats.)

As sailors, wind energy is at the forefront of our lives. The Practical Sailor wind generator test in March 2007 included a prototype of the Air Breeze from Southwest Windpower. Last year, the company debuted the Air Breeze in the alternative energy market for recreational boaters; it is distributed through retail giant West Marine. Using the same criteria as our 2007 test, Practical Sailor tested the Air Breeze for several months under a variety of conditions, using it to charge the ships batteries aboard a Union 36. The wind generators body is cast aluminum, and its blades are made of glass-filled polypropylene. Testers found it quiet, easy to mount, and reasonably priced at $900.