Distributed power systems and NMEA 2000

Just about every modern boat has a network for allowing various pieces of marine electronics to talk to each other. And now the concept of using a network approach to distributing power throughout a boat has gained ground. However, despite the National Marine Electronics Association’s (NMEA) efforts to promote NMEA 2000, its latest networking standard, at least one influential marine equipment expert has decided to forgo NMEA 2000 for a proprietery-distributed power system on his new boat.

Nigel Calder, an Ocean Navigator contributing editor and the author of the authoritative Boatowner’s Mechanical and Electrical Manual, has chosen a non-NMEA 2000 compliant networking product for the distributed power system in his new boat, a Malo 46. The new boat, scheduled for a mid-2008 launch in Sweden, has been selected to receive a distributed power system named Capi2. This product, built by Dutch/Swedish firm called Capi2 Nederland BV, is not plug-compatible with NMEA 2000. To use it with NMEA 2000, a gateway would be required.

NMEA has put considerable effort into promoting their 2000 standard, including holding ConnectFest events at various boat and trade shows in the past few years. These events, which NMEA calls “live demos” allow boaters and those in the marine trades to see how easily NMEA 2000-certified products can be networked. Typically a long network wire extends around the room and a multitude of devices, such as GPS units, chartplotters, autopilots, radars and more, are connected to the single wire. Since they have been certified by NMEA as 2000 capable, they are truly “plug and play.” The network is self-configuring and no setup is required. Units can be plugged into the network and removed from it without causing disruption.

Calder’s reasons for picking the Capi2 system for his latest boat were clear: “The primary reasons I chose it are 1) because it is the simplest system on the market with the least bells and whistles and, as a result, I suspect it will be the least likely to give problems while still giving me what I want, which is remote switching, different combinations of switching, and simple diagnostics; and 2) because its individual node structure makes it relatively easy to hotwire the system in the event the electronics get fried in the nodes, enabling me to revert to a traditional hard-wired circuit. If we get hit by lightning in mid-Atlantic, or have some other electronics disaster, I will be able to get the boat up and running again relatively easily (I’ll have to hunt down the nodes to bypass them, but we’ll build this into their placement so it is not too difficult).”

Capi2 calls its product a bus-based power supply system (12-24VDC) based on a digital bus technology. With this approach, you have one set of power bus cables and from that bus you install nodes and then power various devices via the nodes.

Some distributed power systems have made claims that they are NMEA compliant, however according to Calder, the NMEA has not yet developed much of a message base for power distribution, so distributed power systems are putting proprietary messages on the NMEA bus in the 2000 format. However, Calder notes: “Without a gateway of some sort, the other NMEA 2000 devices cannot display/respond/react to these messages, so you might as well use a less expensive proprietary system.” In the meantime, Calder has been encouraging the NMEA to develop the necessary message base.

It will be interesting to see how NMEA 2000 standard is adapted to accomodate the needs of distributed power systems. According to Steve Spitzer, technical director for NMEA, the issue of increasing the NMEA 2000 message base for distributed power systems is already being addressed. “We’re waist deep in it,” Spitzer said.

Since NMEA is a trade organization, it does not have a large development staff. It works on additions to the standard when its members request them. “We only work on these messages when there is a market need,” Spitzer said. According to Spitzer, three companies recently requested an increase in NMEA 2000 messages for distributed power operation. “So it is something we’re dealing with right now.”

For pure data networking, the NMEA 2000 standard continues to gain adherents via the NMEA’s ConnectFest events and through the steady increase in products that have been certified as NMEA 2000-compliant. Now it looks like distributed power systems will be accommodated within the NMEA 2000 standard as well.

For devotees of DR
Not all marine technology comes in the way of electronic circuit boards and radio frequencies. Sometimes the best in marine technology is taking old standbys and updating them with modern materials. One such example of that is the Navigator’s Tool Tote by a Charlotte, Vermont, based company called Sailor Bags.

With its variously-sized pockets, the Navigator’s Tool Tote is the perfect way to carry your navigation tools with you. It can accomodate parallel rules and dividers and pens and pencils and any other small items you might need for plotting your position. The entire package can be folded over, rolled up and held closed with two hook and eye straps.

The bags themselves are made from the same Dacron that is used to make sailcloth. The difference is that Sailor Bags has their sailcloth made to order and it skips some of the resins used to construct standard sailcloth. The result is a bag that is softer to the touch. In addition to the Tool Tote, Sailor Bags makes a full line of other sailcloth-based carrying bags.

For some people, of course, GPS holds sway and the notion of Navigator’s Tool Tote is outlandish and using a pair of dividers or parallel rules is almost as old-fashioned as square sails and lead lines. For those people Sailor Bags has a solution: a zippered compartment in the larger Tote Bags and Duffel Bags for holding a handheld GPS unit. 

By Ocean Navigator