The basis to these networks has been around for over 20 years but it's only more recently that the makers of navigation equipment, in particular, have settled on the National Marine Electronics Association's 2000 protocol.

Based on the Can-bus principal, a network of relatively light gauge cable runs throughout the boat and carries a modest current. In addition to this power the cable also carries data to and from sensors, GPS units, radar and other equipment so that a device producing data information at one point on the system can transmit this to a receiver in many other parts of the boat.

In addition a control point at one end of the boat can activate a device at the other without the need for cables, carrying high currents, to run the length of a vessel.

The benefits of this are not only the reduction in the costs associated with the cable runs, but also the savings in the amount of space taken up with running these cables through bulkheads and lockers and under bunks and anything else that gets in the way.

There is also a reduction in the amount of spurious emissions of electromagnetic radiation from a power cables carrying high voltages close to sensitive equipment. The reduction in the associated interference problems this can cause can be significant.

Actisense, of Poole, has been involved in this area of technology for many years and now offers a wide range of products, many of which are waterproof: "An obvious point, but one that has been missed by one or two others, " said Phil Whitehurst, managing director of Actisense.

The company, which develops and manufactures all of the components used in an NMEA 2000 compliant network, has been developing, amongst other items, a data multiplexer.

With all of this additional data now flowing it is possible for some parts of a system to become overloaded. This is particularly noticeable with a PC connected. The new NDC-2 helps to filter out data that might cause a problem.

The NMEA 2000 part of the Actisense range allows the user to combine a number of NMEA outputs to one NMEA stream of information which can be viewed and controlled from a number of locations around the boat.

Actisense is not the only company working along these lines. Bristol-based Marine Electronic Services has recently signed a distribution agreement with Maretron, which is a specialist supplier of NMEA 2000 components and cabling.

Plug and play The company feels NMEA 2000 will be a more "plug and play" system with equipment certified to allow much easier interconnection between units from a variety of different manufacturers. They tell us that already, Raymarine, Simrad, Lowrance, Maretron and others are starting to adopt the system, which also allows much faster data transfer rates.

There product line-up includes NMEA 2000-compatible speed, depth, GPS, compass and tank level systems, all of which can be easily linked together using NMEA 2000compatible cabling and connectors.

Most modern radars and radar plotter systems now incorporate an option for "North Up" display presentation, MARPA (mid target tracking) and radar overlay onto the screen. However, in order to get the best from these functions, a very fast and very stable input of compass heading data is required.

To provide this the company has introduced the Maretron high-speed SSC200 Compass Sensor, which features both an NMEA 2000 and the older NMEA 0183 output for easy integration into existing systems. The SSC200 incorporates a solid state sensor and rate-gyro for extremely fast and stable compass heading information. Unlike traditional fluxgate compasses, the SSC200 is not affected by normal magnetic deviation errors. It also outputs data at 20Hz, allowing for a stable display even with the pitching and rolling motion of a small boat.

The price is quoted at £449.00 including VAT.

"As Europe's leading specialist marine electronics supplier, we need to be actively promoting future standards and making sure installers, boat yards and end users have access to the cabling and connector technology so their systems are future-proof, " commented Nick Heyes, who heads up Marine Electronic Services.

He went on: "To help boatbuilders and interested end users understand the new data standards, we have produced a short form booklet explaining the benefits of NMEA 2000."

As one of the big names in this sector Raymarine is naturally keeping up with NMEA 2000 developments and also with natural developments within its own range.

One of the biggest of these developments over the last few months has been the inclusion of the Navionics Platinum cartography package in the E series.

This is something that Andrew Utting, area sales manager for Raymarine, told me has been very well received.

"The 3D charts for a given area are proving to be of particular interest, as is the ability to view this on the split screen at the helm along with location photographs, " he said.

Cosmetic developments Other products in Raymarine's navigation range have undergone some cosmetic developments with slight changes to casings that bring them in line with other components on offer. Some other products have undergone component and manufacturing alterations to ensure they comply with new disposal regulations.

Navionics, the name behind many cartography systems, has seen a good level of take-up of its range of charts, both directly and via equipment manufacturers. One part of the range that has proved popular is the NavPlanner PC planning kit.

With more people planning routes on a home PC the company has seen a need to provide a method of transferring all the navigational data to the onboard equipment.

"Using standard removable memory cards, the system allows owners not only the flexibility of where to do their planning but also an element of data back-up, " said managing director Lance Godefroy.

With PCs being used more and more it's a safe bet that this is likely to be an area of growth in the near future.

Lowrance has also adopted the card based chart system with the launch of NauticPath.

Jim Deheer, marketing manager for Silva, told us: "We aim to provide a cost effective range of charts. With only three charts covering the whole of Europe and including the Mediterranean priced at £149 each, we're looking to make inroads into this part of the market."

It would seem the Lowrance range is aiming at being affordable with its own NMEA 2000 network, LowranceNet, now being available. Components like fuel level and speed sensors retail at £59 each, so they would seem to be coming in well below many of their competitors.

Electronic chart manufacturer C-Map has also recently launched a range of new navigation software, C-eMap, designed specifically for use with PDAs and smart phones.

C-Map, which pioneered the display of electronic charts on early PDAs, has now created a navigation package for these devices.

In the past, it was necessary to connect the PDA to a PC to download the charts and software, or to insert lots of different memory cards with the software and small chart areas on. Now one high capacity SD Card contains both the navigation software and every single chart available for the UK, Ireland and North France.

After inserting the SD Card and, after a couple of seconds wait, the user clicks on the CeMap icon that automatically appears on the PDA's screen.

C-eMap users know their heading and can zoom in and out at will by touching the screen and entering waypoints directly onto the PDA. All the important chart information is displayed, such as: depth lines, buoys, lighthouses, tides, port and marina services etc.

The system is designed to be a portable solution for sailors and motorboaters alike, either as a first introduction to electronic charting, or as a back-up to a larger and more sophisticated chart plotter system.

The system works with most modern PDAs and Smart Phones that are running Pocket PC 2003 or Mobile Windows, but will need a GPS position source in order to use all of the navigation features.

C-eMap retails at £229.00 including VAT. A full choice of areas is available and the buyer selects the most suitable area and orders it from a local dealer.

All of the areas selected and the C-eMap navigation software will be included on the SD card.