This is the "Beast", the unholy mother of all over sized cables on a boat. Its huge square head defies passing through almost any hole or conduit in the vessel. Did I use the word conduit, and boat in one sentence? My apologies for that oxymoronic faux pas. Anyway, I'm not exactly sure what chart plotter manufacturers were thinking when they adopted VGA technology to feed images to monitors and TV's, but they sure didn't give the cabling end of this technology a whole lot of thought.
Here is the Sewell solution. This clever little box was never designed specifically with the boater in mind, but it works admirably with a little creative adaptation. This device costs about $30.00 online, and by adding another $25-$40 dollars for other bits and pieces you can save yourself the enormous agony, and frustration of trying to pull fifty feet of the "Beast" through your boat to the forward stateroom TV. Another thing about inputing VGA to your television empirically discovered by myself, is that despite the fact it may have a VGA input, sometimes they don't like the VGA format being sent by the chart plotter, and you get an "Unsupported Video Format" message, or the ilk on the screen. The moral of the story is to test it first to see what will happen, especially on LCD TV's.
The Sewell VGA to composite video converter comes with everything you need, (almost) to convert a VGA signal to a composite (Yellow RCA video cable) signal.
The output from the chart plotter plugs into the end of the Sewell box with the supplied VGA cable. On the side of the box are the three outputs consisting of composite video (yellow), S-video (not on a lot of newer TV's), and a additional VGA port.
The VGA "Beast" inputs to the box, and the output is the much smaller, and much easier to deal with composite video cable. Another variation on the cabling is to use less expensive RG6 (TV coax cable) and add RCA adapters seen below to connect to the TV and Sewell box. When using coax cable, you might consider adding a ninety degree RCA adapter to the TV if you're short on space behind the set.
When I said the Sewell solution has everything you need, the "Almost" part of this is power. The Sewell box is powered by a USB port, or an optional 110VAC transformer. You get around this power issue by buying a USB charging port ($15-$25) used in cars, and a 12VDC ($10) accessory outlet from your marine supplier. This is all you now need to power the Sewell unit using your vessels 12VDC system. Throw some electrical tape on the outlet, and USB charger to stop any potential walkabouts by the parts, and the power part is done.
The end result is good, but with only 480i resolution, it is not quite as sharp as the VGA cable image. I thought it was an acceptable image overall. In the case of this boat, it would have taken a day, or more to pull the VGA cable, if it was possible at all, and on the other TV in this vessel, I don't think it was possible to get the VGA cable to it without a herculean effort. It is possible to field install VGA connectors, if you have the pin outs, special crimpers and connectors, time, and patience, but patience is all I have on most days. On this boat, the image below (pardon the moire lines caused by my camera) was carried by a composite video cable. On the other TV I used a fifty foot RG6 coax cable with equally good results.
Inexpensive, simple to implement, decent picture quality, low cable costs, and no VGA "Beast" being painfully dragged through your boat. If composite video is not your cup of tea, Sewell also has a VGA to component video converter, and even a VGA to HDMI unit. Now you can lie in bed and watch the anchor alarm messages, and see how close you are to the rocks, or see that coastal weather warning. The TV photo was taken on Don Payzant's gorgeous 50' Nordhavn trawler. Watch for the upcoming electronics make over story on his boat, and a separate piece on the very clever mount for his TV.