Got a cheap 140 quid NASA NAVTEX Pro on my boat (418khz?) . Mounted on the dash. Works well - antenna seems to be able to be placed anywhere and still work so it's velcro-d inside the wheelhouse to avoid drilling holes in the wheelhouse roof. Set is tuned to Niton S and pumps out more extraneaous messages than useful ones - even with the message filters enabled.. However - the weather forecasts are good and the unit stores several days worth on the 80 line screen memory.
I've mounted it with a cigar lighter plug so I can take it home when the boat isn't being used in case I miss a weather forecast. But I get these by fax from the met office or from Solent coastguard twice a day, so the NAVTEX is just a backup really. Good if you're spending more than a day afloat, or sailing away from fax machines, VHF forecasts etc. More detail than the current LW shipping forcasts, plus subfacts, gun facts, lost bouys, moved bouys, shipwrecks, oil spills etc. All human life is there.
Pulls only 40 mA off the battery so can be left on for a few days if you want to return to the boat and find the latest forecast or hazard list waiting for you. No backlight on mine, so useless at night.
Nice thing to have, and could prove useful for longer trips, especially if you cruise away from inshore waters. Scrolling through meesages is quick, but there's always more information than you really want. Last used mine in anger on a trip from Ramsgate to Cowes. Just kept an eye on messages as they came in - in case a freighter had sunk in the Looe Channel.
If you a 2001 Reeds Alamanc there's a good description of what you can expect on page 88.
Perhaps of most use to either gadget freaks (cough) or offshore passages.
A number of gizmos now available for NAVTEX on Palm Pilots, laptops etc. A seasons worth of Met office faxes are cheaper if you want synoptic charts and three day forecasts.
Other Nasa options might be the Navtex engine which will deliver Navtex information to your laptop or home computer (£109), or a retro fit for all Nasa TARGET Navtex receivers the 490 aerial and switch box to receive the inshore forecasts (£59). If the Target Pro is too much the original Target Navtex Standard with the new aerial is still out there (£149).
strongly recommend the ICS paper printer navtex if you dont care about cost. The paper read out is much easier to use, save the messages you want bit like post it notes. Also the buzz of the printer reminds you to look see you have a message.
But a great bonus feature is that it works as a log too. Feed the NMEA in from your GPS and it will print your lat long, cog, spd, time every 15 mins so you have a great log written on paper, which saves you the hassle of writing the log yourself, fantastic, great safety device.
The NASA range is cheap and cheerful, the Target Pro plus, giving dual band coverage being best value for money. You do need to have their active antenna for it to work adequately The standard doesn't have enough memory to cope.
A word of warning, the screen becomes illegible in hot weather (32C+), not that you're likely to get that in UK waters.
The ICS thermal paper rolls are expensive and don't last long unless you are severely filtering out the information, but you can get round that by cutting down cheap fax rolls.
I had an ICS, but got fed up with all the waste paper it ejected. Just bought the Furono great piece of kit. Got it from Cactus--- lokk at their web site and you will get full spec. and a good deal