GPS & Computer vs. Handheld GPS or Fixed Chartplotter.

[mahalocd36]

Hopefully my article will make this months (Feb/Mar) Masthead newsletter. I describe setting up your own chart plotter on a low cost laptop. If you already own a Windows* laptop it's cheaper than you think. That was my unbashful attempt to get you to read the article.

Yes it did, it should be out next week.

[Jim Davis]

On having a laptop on board, I do carry one and use it. However my primary use is communications, not navigation. I have several navigation programs loaded into it and originally thought it would be nice to use it in route planning. I quickly learned that with the variables of long distance cruising that preplanned routes don't pay off. I have found it much better to plan one day at a time and after consultation with my Chief of Staff set up the next day after dinner with the chart book in hand. On a Garmin it is simple to use point and click to put in a route. The same process that is used on the laptop and I don't have to then transfer the route to the chartplotter. My Garmin can also stay in the NEMA mode so I don't forget to switch it back and forth. For my purposes a route will be minimal and safe sided for inclement weather. As to actually following the route religiously, I don't unless the visibility is bad. The GPS is only advisory and the chart lives on deck. I also try to plan routes that avoid running a buoy line. In fog, or rain power boats tend to go buoy to buoy and that is the last place I want to be.

I have found the laptop, as a navigation tool, cumbersome and a power hog. Even with a bright screen, hard to see and the last thing I want on deck. For a power vessel with an enclosed pilot house and continuous power generation this could be a different story. My chartplotter isn't large enough for me to want to clutter the screen with AIS data. I do not want a screen that big on deck. I have, and know how to use it, RADAR collision avoidance with ships in the fog isn't a real problem. Now little guys like us can be a problem. Fiberglass and wood do not make good Radar targets. Even with the best reflector small boats do not show up well on small craft RADAR, especially if they are "end on". I know the comercial guys would like to see everyone have AIS and RADAR, but most reasonable sized sailboats don't have the battery to support it. Much more important is for people to use their eyes and common sense.

One other thing that I see with electronic navigation is the tendency to put large chartplotters at the helm. This may be nice for steering a precise course, but too often not conducive to keeping a good lookout or noticing minor changes in the wind. At night these same people will enter a small creek with full bright and therefore can't see beyond the screen. I have pulled boats off because their course, set by chartplotter, was on the wrong side of a buoy and had to maneuver in Rules of the Road violations because of the chartplotter/autopilot interface. This is not to say electronics are bad or evil, it is to say be careful and exercise caution. There are too many that rely totally on electronics. It seems that less people are able to simply enjoy being on the water, perhaps it is too many "Reality Shows" on TV.

That said, I will admit to using the laptop to plan routes when I am preparing a boat club cruise. I set up routes in advance to make sure the legs are comfortable for a 5 knot boat and allow plenty of time for a post-coffee start and afternoon cocktails. This also warns me if a pre-coffee start will be required. This route information is normally not given to the others, just the projected days run and departure time.

[fenixrises]

Hi all,

I have used a simple Garmin eTrex GPS as my primary location tool. It is not interfaced with my laptop but can be. The only problem is that the eTrex needs a clear sky view and as far as I know does not have the option for an external antenna.

I was gifted a version of CMaps and the charts for the whole world with it. So far all has worked fine. If I need to see the chart for the area I usually set the laptop on the chart table with the 12V adaptor plugged in to the ship's electrical system. So far this has been rarely needed.

I enter waypoints prior to departure and usually stick to them, except at the end of a passage. Then I sometimes need to make changes on the fly.

But I have not done a lot of close in sailing along the US east coast, or in bad or foggy weather. So that would probably change things a lot.

As for power consumption that has not been a problem for me as I rarely use the laptop except when approaching land, say the last 20 miles or less.

One way to dramatically reduce power consuption is to remove the laptop's battery. Much of the power consumed in a laptop is to re-charge the battery and that is a constant load. Most newer laptops are 19V so a step up adaptor is needed. My laptop, with battery installed, draws far more current than without the battery. If you have an older laptop it may use lower voltage. My old Toshiba needed only 15V and would run on well charged main batteries with no step up in the voltage.

As you may know my old Toshiba took a dring of saltwater and died. So that is a concern. The new Acer is peforming very well.

I met a fellow sailor in Simon Town who had two computers on his boat, plus a laptop. Now this was a big fancy boat and the guy had bucks. But what he did seemed very resonable. His computers were quite small units, about 7~8" square and around 2" thick. They were made to work on 12V and used in automobiles, mounted normally in the trunk. This is a good idea.

All connections were there for periphrials, CD/DVD drive, mouse, keyboard, monitor, etc. It could be interfaced with all his nav instruments and autopilot. He used a wireless mouse and keyboard so had no wires on the chart table. This main unit was mounted below at his nav station. He had another unit with monitor up in the enclosed mid-ship cockpit. It could be seen from the helm.

When he bought the units they were around $500, now I would guess they would be maybe $300. Add to that a $200 LCD monitor, a remote CD/DVD drive and mouse and keyboard and you're set.

Since most nav stations are near the companionway it would probably be a not too difficult task to mount the monitor on some type of swing arm. That way it could be moved to a position of easy visibility. If positioned under the cabin top at the forward end of the companionway it would be visible and pretty well protected by the dodger, etc.

I may give this system a tryout in the future.

Take care,
Fred

[Dave Jeffery]

Anyone tried the iNAVX application for the iPhone, which is advertised as providing real time position on raster charts via GPS? Useful?

[barfwinkle]

I got a usb antenna last week, it got here Friday, so I plugged it in, found the com port the computer/software assigned it opened the navigation software (Seaclear II - Free) and it worked GREAT.

It also worked with Maptech Offshore Navigator. Way kewl, and the antenna was $39.95.

THe antenna will receive thourgh the coach top and even at the house it shoots through two roofs and still gets a fast and good reading.

I'm a happy sailor.

Fair winds

[MarcMcCarron]

This is the only way to go.

I use GPSNavX ($59 download) software on my mac with a
BU-353 USB GPS ($35 on ebay) . My charts are free from
NOAA.... and always up to date, thank you government.

It's perfect in every way.

80% of the time I use a tiny gps hand held
(just the numbers - not a plotter) that I picked up
on Ebay for $60. It eats two batteries every 12 hrs.
I get VMG and position. I use a paper chart (book) in the cockpit
and track my whereabouts manually; simple is best.

At night It's 100% GPS laptop in the cabin. The software even makes the screen night vision friendly by using black maps with red soundings.

The GPSnavX web support is wonderful. Great product.

At anchor my 17" screen is perfect to watch movies. Mac
laptops are the only way to go.

[barfwinkle]

I too have the BU 353. I am glad to hear about the Apple software and yes the NOAA charts are great.

Thanks for the info.

It was 80° here today and now a freaking cold front is blowing through!!!!! Crap, oh well

Fair winds