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Scotch Mist, Sorry if my ramblings were a bit confusing. Here is another go....
Hanse fit Simrad instruments as standard (unless you ask them not to, which we couldn't as the boat we bought was already built). As standard there is a depth sounder, a speed/distance log, the black box that they both plug into, and what they call a Combi display (the latter mounted either on the steering binnacle instrument pod or over the main hatch, depending on whether you have tiller or wheel steering). All of these are part of the Simrad IS15 range of instruments.
There are a number of alternative vendors of instruments but my two faourites were Raymarine and a new company called Tacktick.
The unique features of the Tacktick instruments are that they are solar powered and talk to each other via radio rather than cables.
Raymarine's products are similar in concept to the Simrad ones. Both are connected up using their own proprietary cable based communications protocols. Seatalk is the name for Raymarine's protocol and Roblink is the one for the Simrad IS15 instruments. Confusingly Simrad also have a newer protocol for other products that is called Simnet!
The Simrad IS15 instruments are actually quite expensive so I didn't want to throw away something like £600 worth of speed and depth instruments and start again with another manufacturer. For mostly cosmetic reasons I also decided that I didn't really want a mixture of manufacturers equipment.
So, given that Simrad stayed it was then easy to decide on the IS15 Wind instrument to be added. This is fairly straight forward as the sensor at the top of the mast is cabled down to the same black box mentioned above and the new display is just cabled up to the existing Combi display. All of the IS15 display are in a kind of daisy chain arrangement on a single string of cables from the black box.
The nice thing about the IS15 displays is that as well as having two of the Roblink sockets (for daisy chaining as described above) they also each have an industry standard NMEA port. The NMEA port can be used to either talk to, or listen to, another instrument or device (that supports the NMEA standard) whether it is from the same manufacturer or even another one. This is where it gets more fun and more complicated....
So we have a depth transducer, a log transducer and a wind transducer all connected to the Simrad black box. That is then cabled to the Combi instrument using Simrad's Roblink protocol and that is then cabled to the Wind display. OK so far?
Now, the wind display also sends data out of its NMEA port to the wheel pilot. It will send any and all data that it can receive from other devices. In this case we are interested in it sending wind angle data so that the pilot can use it to steer a course relative to the wind. As standard the pilot can obviously steer relative to its built in electronic compass.
Now we really get complicated! The Garmin GPS/plotter is connected in to the NMEA port on the Combi instrument. That means that any NMEA data that it outputs (e.g. speed over ground, course over ground, course and distance to waypoint......) is received by the Combi display and then resent out on the Roblink connection. As I said above, everything on Roblink is sent out as NMEA by the Wind display. That means that the wheel pilot not only gets wind data but also data from the GPS/plotter.
OK, so what does that all mean in practice?
The WP32 wheel pilot can:
Steer to a magnetic course using its own electronic compass Steer to an apparent wind angle using data from the Wind display Steer to a waypoint using data from the GPS plotter (that came via the Combi, Roblink to the Wind, and then NMEA to the pilot!!!)
The Combi can display:
Speed Depth Wind angles and speed Course over ground, speed over ground etc from the plotter Distance and course to waypoint from the plotter Loads more that would take forever to type..... ....and it can do it in all sorts of combinations which is why I like it.
The GPS/plotter is a Garmin 172C which has a 3.5inch square colour display and can utilise Garmin's Bluechart cartridges. The screen is not very big (when you are used to even the small paper chart folios) but you can zoom in and out at the press of a button. It is big enough for use at the wheel and the unit fits nicely on the instrument pod.
What I said I had discounted was:
a large GPS/plotter down below radar a bigger plotter or display at the wheel linked to the two items above
On a larger boat, with more space at the wheel, and if you sail further than we do at the moment, then these additions/changes coud make good sense. The possible issue is that an instrument/plotter/radar display pod that is big enough for a large screen will take over the cockpit and look far too big. It might also be tall enough that it is too close to the boom for comfort.
My view is that the market is changing rapidly, prices are falling, and in a year or two we could buy more capable equipment of this type for less. It all depends on what you want to do today and what you are prepared to spend.
I probably ought to add that I didn't really want to drill holes and pull cables through my nice new boat so Aztec (at Hamble Point) supplied and fitted the extras. It is obviously much cheaper to do it yourself but they know where all the cable runs are, what cables already exist, and have all the tools and experience. They could also do the mastwork before it was rigged which makes life easier. Hanse will put you in touch with them if you ask, or I can.
Phew....sorry for the long post and I hope this helps.
Regards, Andrew
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