Handheld GPS/Chartplotters

[Minnewaska]

The portable GPS navigation systems available for the aviation industry are, by far, more capable than the best handheld unit available for the marine industry. Use Garmin as an example. Here is one of their top of line aviation handhelds, which you can mount with hardward to the yoke, glareshield, whatever.

https://buy.garmin.com/shop/shop.do?cID=156&pID=14859

Pricey, for sure, but even models that are more comparably priced to marine unit are incredible more capable, IMHO. These av units have charting, terrain awareness, navigation, satt weather, airfield databases, etc. Simply put, they have all the marine capability, plus 3 dimensional info.

Why isn't a much more capable unit available for marine use? At the least, this model above has a usable 7 inch screen.

Rather than buy any of the portable marine GPS, I'm seriously considering an Ipad with integrated GPS and a charting app. By comparison, it seems to me that the marine GPS offerings will become obsolete (already are in fact).

[sailingdog]

Unfortunately, the iPad isn't waterproof or very shock resistant, and would die in a marine environment fairly quickly from spray or impact. I also wouldn't call a unit with a 7" screen a handheld...a portable or transportable, but not a handheld really.

Also, at $3600, that unit isn't really comparable to the marine units, since it is an order of magnitude more expensive.

[Minnewaska]

Originally Posted by sailingdog

Unfortunately, the iPad isn't waterproof or very shock resistant, and would die in a marine environment fairly quickly from spray or impact. I also wouldn't call a unit with a 7" screen a handheld...a portable or transportable, but not a handheld really.

Also, at $3600, that unit isn't really comparable to the marine units, since it is an order of magnitude more expensive.

You are essentially right about the Ipad, however, they make waterproof and hard cover cases for them.

I acknowledged that the aviation units are more expensive, but you are getting something that is portable and a truly functional alternative to a mounted unit. My example is about the size of a hard covered book, which is easily handheld, and you can actually read useful data from the screen at arms length. They also have much less expensive units that still have larger screens and capabilities far beyond marine handhelds.

My question is why there aren't comparable marine units, with larger screens and the full capabilities of a mounted unit, even if at higher prices?

[SVPrairieRose]

Well, since your unit lasts 2.5 hours and weighs nearly 2.5 pounds I would suggest that a SH CP300i with a few 6v lantern batteries attached would be a fair compromise. At less than $800 all in you have lots left over for other things. As for the ipad, if it has the same gps quality that I get with my iphone with navionics then you are going to crash your boat. My iphone is a toy, with a lot of great features, but a toy none the less.

[sailingdog]

Part of the issue is that there is little demand in the MARINE market for a portable large screen MFD GPS type device. The cockpit of most boats is open, and as such, anything that isn't permanently, or semi-permanently mounted is liable to fall overboard. This is generally not the case with most aircraft.

Sealing and ruggedizing the units for marine use adds to the costs of the unit.

Also, the data that is involved is probably a bit more than you have in the aviation units. Terrain height is in some ways of less importance except near airports, since most planes are used for transport from point A to point B and otherwise fly at a fairly significant height. Boats do not have the luxury of being able to change their "altitude" and the depth of the water becomes a serious issue, especially since boats are often far less maneuverable than aircraft and more at the mercies of their environs in many ways.

Also, IMHO the data for aircraft requires far less granularity than does marine use GPS units. When you're moving at 130 knots, the data points need to be further apart to prevent information overload. When you are moving at six knots and have much more limited ability to dodge, being limited to two dimensions effectively, then the data set needs to be much more complete.

Finally, I'd point out that Garmin does make a dual use transportable unit that is very similar in many ways to that $3600 unit but designed for terrestrial and marine use. The Garmin GPSMap 640 has a 6" screen and has both marine and terrestrial navigation capabilities. Like the aviation unit, it is capable of receiving XM WX real-time weather data as well. It also supports AIS and DSC input and display as well, but is significantly less expensive, at $1000.

[Minnewaska]

Originally Posted by SVPrairieRose

Well, since your unit lasts 2.5 hours and weighs nearly 2.5 pounds I would suggest that a SH CP300i with a few 6v lantern batteries attached would be a fair compromise. At less than $800 all in you have lots left over for other things. As for the ipad, if it has the same gps quality that I get with my iphone with navionics then you are going to crash your boat. My iphone is a toy, with a lot of great features, but a toy none the less.

Plug it into a DC outlet in the cockpit. That's how they are used in the plane cockpits as well, some have adapters hardwired.

A $100 add-on gps antenna and software and the Ipad is as good as any gps receiver out there. I will report in the spring whether it is even necessary.

You are clearly going to crash your boat while distracted looking at these miniature marine handheld GPS screens. Can we freeze frame this voyage while I go look for my reading glasses?

I suppose, to be fair, you have much more time to focus, even go look for your glasses, and consider your next move at 8kts, than you do at 200kts.

[Minnewaska]

SD, I am both a pilot and sailor. Granularity of data is simply relative to the amount of time it will take you to cover the ground and get in trouble. I'll call that even.

The big difference is the clarity and completeness of the data, where interpretation can be made quickly and aviation units far excel.

In the plane, I have to avoid the hard stuff around the edges of the airspace as well as other aircraft. They close in on you in seconds. When making a descent to landing (there are no anchors on planes, you must dock each and every time regardless of weather), you must avoid other aircraft and terrain by precisely following published three dimensional courses and altitudes. You don't get to change at will. In the boat, you must avoid those areas of unacceptable depth, but you don't actually have to manage that third dimension. In the plane, you need data that is easy to interpret at a glance, because all of the above are routinely done in zero visibility. By the way, I also find that input and adjustments for flight plans is also easier than routing on marine GPS.

Ironically, you are not allowed to legally use a handheld for instrument flying, even though they are far more capable than their mounted counterparts. That is strictly a result of the bureaucratic FAA certification process.

I'm beginning to realize that the more capable GPS systems are not made for us sailors, simply because we don't have as critical a need for it.

Let's face it, I've never left the plane's yoke in the hands of an amateur so I could go to the bathroom!!

[sailingdog]

Originally Posted by Minnewaska

Let's face it, I've never left the plane's yoke in the hands of an amateur so I could go to the bathroom!!

I would hope not...

[brak]

One important difference is - there is a lot less "stuff" on those air "plates" than on even a basic marine chart.

So, your aviation GPS can concentrate on core functionality - where you are, where you are going etc.
Your marine unit has to display a ton of visible chart data (not all of it very important at all times, but as multiple discussions here have shown - people feel strongly about this ), and then deal with items that are of no particular practical use but are "expected" by mariners.

I am not sure about aviation GPS interface - I've seen a few (not a pilot, so not a professional opinion) and didn't find them to be very intuitive. Certainly no more so than an average marine unit - which is not to say much.

[Minnewaska]

Originally Posted by brak

One important difference is - there is a lot less "stuff" on those air "plates" than on even a basic marine chart.

If you are referring to an approach plate, used to make an instrument approach to a runway, I agree.

However, an aviation multi-function display (as many av GPS have become) can display as much or more data enroute. In fact, I shut some of it off so that I can more easily interpret what I must know.

My MFD displays all surrounding airfields and waypoints, a weather condition flag at each, my flight plan route, ground speed, altitude, course over ground, time to waypoint, time to destination, current time, restricted airspace, geographic markers like road and rivers, warnings for turbulence and icing, overlaid satellite weather, overlaid traffic with conflict identifiers, all on top of a color topographic terrain map. The GPS will calculate the vertical descent speed to arrive at a given altitude and a given distance from your destination airport and whether you will violate a buffer to any terrain obstacle on your current heading. Mine is panel mounted. The aviation handhelds can do even more, including simulated flight instruments.

With the flick of a knob, I can see current weather and forecasts at each airport along my route or any approach plate into any runway on my flight plan.

Marine chartplotters are close, but marine handhelds are lacking. In the cockpit, I have two installed GPS plus an MFD, along with several old school nav radios. I still keep a handheld GPS in the seatback, for an unlikely complete electric failure, which I bought nearly 10 years ago. That unit is still easier to read, with a bigger screen than all but the Garmin 640 that SD mentioned above.

Since I have a chartplotter, I'm really only interested in the same backup concept. I'm still thinking I will give an Ipad in a waterproof cover a shot. I'm sure there will be a way to mount it so that it won't knock around the cockpit. I'll let you all know.