GPS v Plotter? Fixed v Handheld

[(195)]

Can anyone explain the difference between a GPS unit and a plotter?
Is it better to have a fixed or handheld unit?
Which is more useful as a navigation tool?
What extras do you have to buy to make it work?
Please help - I am totally confused by all the different units on the market as they all appear to do the same (I'm sure this is not really the case).
Does anyone have any recommendations on what to go for? I am looking for a simple to use unit that will help with costal navigation on a 24ft sports cruiser.
All advice gratefully received.

 

[tony_brighton]

Plotters and GPS borth work off the GPS satellite system for positioning. The big difference between the two is that the plotter also contains a digital representation of your paper-based charts so you dont need to muck about as often with pencils and rules etc.

(Before anyone complains - its still worthwhile having a paper chart as a back-up if the power on your plotter fails - and to have a recent position on it).

GPS will give you all sorts of useful features, the best one of which is 'you are here' in Lat and Long. The rest of it (Speed over the ground - SOG, distance/bearing to waypoints, Course over the ground - COG etc etc) is in my opinion a huge bonus. But in essence you have to use GPS with a paper chart.

With a plotter, you usually have your charts digitally stored on a cartridge (can be expensive - worth checking the prices for the relevant type but I just paid £200 for Solent & Channel Isles on a CMap-NT wide format). The more areas you sail the more cartridges you need. You still have all the GPS functions mentioned above but its all displayed for you on the electronic chart including things like historical track.

Given the above there is a huge range of differences in products available, for example a colour plotter will set you back hundreds more than a b&w. Hand-held GPS units are so cheap these days (c£100) that its always worth having one as a back-up, but with a sports cruiser I'd say go with a plotter and make sure you can see the display from the bridge - assuming you can afford it! Prices range from around £500 for a b&w upto several £k for the dogs whotsits; but note that if you want good clarity in sunshine you probably need a colour unit.

 

[ChrisJ]

Pay your money and take your choice....

My choice was a hand-held.
- Can take it home and use it in the car (my cars speedo is 12% wrong) or when walking or when using a car ferry across the channel etc.
- Can practise at home, so its easy when on the boat.
- Can enter way points while at home.
- Can plan routes while at home, along with paper charts.
- Paper charts are harder to go wrong, as well as being cheaper.
- Old paper charts are useful as demonstration or practise items, as well as general passage planning at home.

- BUT its easier to leave it at home when it should be on the boat!!
- It goes through the batteries fairly quickly.
- It has a small display (which seems to be getting smaller each year!).

Cheers,

Chris

 

[bob_tyler]

You car's speedo may not be the problem. If you are rounding a bend, the GPS will have measured the distance across the chord of your course and thus indicated a much slower SOG than your road speed.

The more worn your tyres are, the faster the speedo reads as the wheels have to turn more revs for the same distance.

The best method for a speedo check is a stopwatch over 1km of straight motorway.

If your speedo is 12mph fast, please keep in the left hand lane at an indicated 70mph or you may be forcing others to slow to 58mph and they will rightly be annoyed.

I know this is a sailing forum, apologies to any reader who is offended by my non-sailing reply.

 

[tonyleigh]

This is dangerous (!!!) but I'm trying to read between the lines - especially your final comment. A relatively cheap (£100 + power lead + bracket), easy for you to see, hand-held "fixed" securely by your steering position and running off your boat's battery (eg through a cig lighter socket) would allow you to familiarise yourself with what is a very sophisticated technology. It may suffice you for a season or two by which time you will be able to judge whether to up-grade.

 

[Guest]

You have had an excellent response regarding what a plotter is but I can suggest another option which is what I have ... a Yeoman plotter! It holds paper charts so you don't lose them! I already had a fixed GPS but you can get a model with GPS built-in [I'd still probably have a separate] and it is excellent and particularly good for fast cruising when you don't have time to start messing about plotting positions at 20knots+. You can route plan with it, upload waypoints to the GPS, it will tell you where you are on the chart so you can mark it [the chart has a plastic covering] - go and have a look at one or check out www.yeomanuk.co.uk - they even have a downloadable demo!

I would highly recommned it for fast craft!

 

[david_bagshaw]

I am another firm believer in the Yeoman, for the real navagation, and lap tops for planning , interest,keepin waypoints etc.

I have never had a plotter of the type that needs chips or cartdridges, , put off due to the costs, for last years voyage alone the cost of cartdridges would have been thousands, + the correction fees.

Much prefer paper + web derived notice to mariners etc. web addys for NL , germany , denmark and uk on my site


David

See my web site www.yachtman.co.uk

 

[Guest]

A GPS and Plotter are two different animals. A plotter does not have to have GPS capability. You can therefore buy both. A plotter with the handheld GPS interfaced to provide ship cursor and navigation info.

The main difference between fixed and handheld is that handheld do not have the same capabilities as the fixed.

A fixed GPS Plotter on the other hand would in normal circumstances be connected to the autoplilot, tillerpilot or wheelpilot. An NMEA output from a fluxgate compass would provide heading info for north up, course up display etc.

Determine what you want to acheive and what you have to acheive it and take it from there.

 

[Guest]

I was going to leave it to the rest of the Forum to give you the best advice until I saw the phrase "muck about with charts"!!!!!!!!!

Even with the best and most expensive bits of electronic kit on the market you should still "muck about with charts" (i.e. know where you are on a bit of paper).

I've worked with computers for over thirty years and I still don't trust them to be there for me when I need them.

"Bit of paper" - I agree it's not easy to keep it updated and it can get wet, limp, scuffed and dirty but at the end of the day it will be THERE and it WORKS.

Electronic charts and equipment is (relative to a paper chart) less reliable than a heroin addict in need of a fix. Voltage "dip", electrostatic discharge, magnetism - they can all b*gger up the system. (Apparently in Belize they have even found a bug that eats CD discs!!)

My advice is that if you are at "stage one" with electronic navigation kit go for a handheld GPS and use it to fine tune what you see on the paper charts.

Best regards )

Ian D

 

[Grehan]

We're fairly new users, but . . .

(a) We've got a portable GPS, which is good because we can practice with it at home. Did I say practice, I mean play around. This is v.important. After a few weeks/evenings/weekends we've become reasonably confident with what is after all an amazing bit of kit - even if reasonably cheap nowadays.

(b) Were also initially confused with what Chart Plotters were. Decided against putting all eggs into one rather expensive electronic basket, however convenient.
Got a Yeoman and it's damn good. I also think it's safe, because updating ones position onto the paper chart (which is not electricity dependent) (and is much bigger than any Plotter screen) at frequent intervals is no chore and is therefore actually done. And a vital task, too.

Version of Yeoman that includes its own GPS might be worth considering, but the combined thingy needs 12v supply so not so convenient for playing with.

Only snag we've discovered with the Yeoman is that the actual full plastic envelope area does not correlate with the 'active' area. So (for example) a complete Small Craft Portfolio chart does not get covered - a margin round the edge (that's what a margin is, I suppose . . .) doesn't 'read'.

Anyone else find this?

----post script further thought -----
Compass do a "MLR GPS and Yeoman together" cheapy deal. Or did. Not that I'd recommend them - first time round got the MLR GPS plus a motor boat steering wheel instead of the Yeoman. Took 'em ages to sort it out. Not very impressed. But they are cheap and also quite friendly and helpful. You get what you pay for, I guess. Probably.<P ID="edit"><FONT SIZE=-1>Edited by Grehan on Tue Jun 19 17:44:22 2001 (server time).</FONT></P>

 

[Guest]

Others have explained the difference between GPS and plotters, so I'll only comment on my personal experiences with GPS/electronic plotters/Yeoman.
On my 37ft power boat I started with a Garmin 12 handheld with a 12v power cord and mounting bracket (the GPS itself is reasonably priced, but the accessory prices are high). I did my route planning at home and manually entered waypoints into the 12 from paper charts. It was then simple to mount the unit in its bracket on the boat, plug it into the cig lighter and go.
A couple of years later, I installed a fixed GPS, Garmin 126, but was still able to plan at home using the GPS12 and transfer waypoints to the GPS126 using the interface cable.

I then began looking at electronic plotters and was able to use b&w and colour on friends' high speed boats, but I could not get used to the small picture and need to zoom in and out and then find the right place on the chart. The best I've seen for size and clarity is the Northstar. It's very expensive and has what looks like a 12" diag screen.

After some research on this forum, I bought a Yeoman which I can interface easily to my handheld GPS12. Its first real use has been over the past couple of months and I've found it invaluable. We planned and executed a 1000nm cruise from SW Florida, through the Keys to Ft Lauderdale to the Bahamas (Abacos) and back. We returned home yesterday. The planning consisted of transferring WPTs directly from the Yeoman to the GPS 12 at home, using their interface cable ( I could have done it on the boat) and then using the Garmin to Garmin interface cable, transferring the data to the fixed GPS aboard (this one is interfaced to my autopilot). En route, the handheld can be left attached to the Yeoman and will allow you to see exactly where you are on a paper chart at any time. ( If it's left attached, it has to run on its own batteries, by the way, but they last for at least 8 hours. I use rechargeables(sp?)). I think that on a 24ft boat, the Yeoman might be a bit big to handle at the helm, but that depends upon your boat's layout. In any case, the described set up is far less expensive than the electronic route, it allows you to grow as your needs grow, it's very easy to use and you have the advantage of the "big picture" of paper charts. Hope this helps.
p.s. as another contributor noted, the Yeoman cursor does not "sense" to the very edge of the chart, but it's a minor problem.

 

[Guest]

I have already said enough about the Yeoman and it appears a lot of other people like it too and yes there is a margin but usually at that point you are ready to shift to the next chart and you can offset the paper chart in the plastic envelope slightly so one corner is not dead?

Actually I have scanned, magnified and printed sections of charts of areas that I use a lot and for those who don't know the Yeoman - it will 'read' any chart [homemade or commercial] as you reference each chart by using 3 points on the chart and it then knows where you are on the grid?

There are a few comments about handhelds and fixed and using handhelds at home and tranferring waypoints, etc ... Guys, do what I did and buy yourself a 12v transformer fit a ciger lighter socket to it and use the fixed GPS at home [assuming you haven't glued it into the dash]!?

Another comment was that a Yeoman may be too big for a 24' - could be right, but no more cumbersome than trying to look at folded charts, etc ? Look at www.yeomanuk.co.uk for more details ...

 

[Guest]

At last like minded people. I've been using a Yeoman interfaced at first with a Navatar decca set and now with a Garmin 128 and have travelled 100's of miles without problem. All these plotters are great to play with (and I've tried a few of my friends ones) but when the chips are down its nice to have a piece of paper there with all the details of the area at hand. Charts are cheaper than chips and by doing your own updates you realy get to know your area.
The Yeoman / GPS system is a cheapish, reliable and simple answer to modern navigation and long may it last.

 

[Guest]

Re: help for malcolm

Right, all the answers so far have been a bit technical. Here's some non-teccy.

A gps and a "plotter" are nearly the same thing. A plotter does all that a gps can do, plus a bit more. Sometimes plotters are called "GPS plotters" or "chart plotters".

First, a gps. They are indeed all abou the same, cos they all use the same bunch of satellites up in the sky. It uses these to work out a lat and long of EXACTLY where you are on the planet, and display it on the litle screen. It can also tell how fast you are going (in mph or knots) and in which direction.

Also, with a gps, you can type in a lat and long (as N and W) or where you want to go which you can do in the shop before you buy it or get the guy to do it, and it can remeber it. These are called "Waypoints". Then you press GOTO and select that you want to go to that point. The GPS tells you how far away you are from that point, and (at current speed) how long it will take to get there (usually called ETE Estimated or Expected Time Enroute) and at what time you will get there (ETA) again at current speed.



All the above can be done with a handheld, usually costing around 100 quid. It uses batteries, but you can get an adapter to plus into a 12v socket. Garmin are probly the market leaders, and nice people if it goes wrong.

Right, plotters, a.k.a. GPS Plotter does the same as above. But inside its electronics it has an electronic map. It can display this map, and put a little marker on the map of exactly where you are. These have bigger screens, and are bigger, because instead of showing just numbers as the gps does, it has to display a map. But it's really a gps, just with a map as well.

After a while with a gps plotter, you find that you don't really need the map function except to show wife "where we are". You can get little "chips" to slot into a gps plotter which hold fine detail of the local region. These allow you to see, for example, the layout of a harbour and even the numbering of the pontoons. But you could get the same from a pilot book.

Best thing would be:
1. Buy a handheld Garmin GPS 12 or whatever for 100quid ish
2. Turn it on and it'll show "where you are" as a N and E or W.
3. Use paper map to mark with pencil map an X of where you are every so often as you drive boat along.

4. Then, once you ok with above, use the GOTO (waypoint) as expliianed further above.
5. Be careful : the gps will not warn if there is a headland in between you and the target waypoint, or a brick wall or anything, it just points to where the waypoint is from where you are. Depth etc are unknown to it. best put in waypoints which are (say) 1/4 of a mile from the harbour entrance. ALSO, be very careful that the waypoint is absolutley correct: a single digit error can be disatrous as you head off to the wrong place. Checking against a paper chart is always good.

6. Once you have got benefit from a handheld, praps think of a plotter. On a 24footer, tho, it may not be worth it - most benefit is to be had from the handheld.

 

[h4nym]

Re: Car speedo 12% light

Folks

When I first checked my GPS SOG against my speedo (on a straight piece of the M40) I was initially confused at the inaccuracy. But it's a BM, I kept on consoling myself - at least it's better quality rubbish than a hundred quids worth of Garmin rubbish! Then I worked out how to get my Garmin to display MPH rather than knots!

On a more serious note, as well as a GPS Plotter onboard, I also have a PCMCIA GPS Card in my laptop. Coupled with a cigarette lighter inverter and Microsoft Autoroute Europe, it's a damned sight cheaper than a car sat nav system, and Navmaster on the laptop is a reassuring backup to the plotter. If you have a laptop, get the card. http://www.premierelect.co.uk/pcgps.html was where I got mine. And by the way, if you do get one, get the external antenna. Apparently the antenna in the card is disabled by default!