Paper Charts or Just Electronic

[jackdale]

Originally Posted by Simi 60

Really?
A lead line?
And dicking around with it in a busy harbour entrance?
Sounds like a recipe for disaster.

Why not simply have redundancy.

I use a lead line to measure the depth under my rudder when I anchor stern-to shore.

Do you think I have have a depth sounder on the stern?

[Adelie]

Originally Posted by SV Windrush II

I am amazed that people would suggest replacing the compass with a GPS, how would you stay on heading watching a GPS? The position on the screen is delayed, you would have the sever case of the drunken sailor syndrome. I have my GPS on with the tracking everywhere I go, but when I need to stay on a heading I am using my compass.

Sarcasm.

[Simi 60]

Originally Posted by jackdale

I use a lead line to measure the depth under my rudder when I anchor stern-to shore.

Do you think I have have a depth sounder on the stern?

Plenty of boats do have stern mounted transducers.
I have a small less than $100 transom mount garmin on the big boat as well as an incredibly noisy depth only transducer towards the bow, and a commercial quality fishfinder transducer amidships.

Even our tender has a transom mount transducer.

[SV Windrush II]

Originally Posted by StuM

Who suggested replacing a compass with a GPS?

I see several comments on here that suggest some people are using their GPS instead of the compass. I think for short costal passages that they can see navigation aids it’s ok, but still I always use my compass for referencing my heading

[El Pinguino]

I know of boat..... Swiss..... currently in the SW Pacific.... when they were on the far side of the Pacific they were planning to remove the compass as they couldn't see it anyway.... had built a cockpit table over the top of it.... don't know whether they did or not but they had gone an awful long way like that.

[Simi 60]

Originally Posted by SV Windrush II

I see several comments on here that suggest some people are using their GPS instead of the compass. I think for short costal passages that they can see navigation aids it’s ok, but still I always use my compass for referencing my heading

Plotter screens have heading reference lines that extend for hundreds of nm if so wanting.

When we were sailing the only time we ever hand steered was racing or coming into port.
All other times autopilot on and concentrate on sail trim, nav and situational awareness.
Should add, back then we never had a plotter.

[Jim Cate]

Originally Posted by SV Windrush II

I see several comments on here that suggest some people are using their GPS instead of the compass. I think for short costal passages that they can see navigation aids it’s ok, but still I always use my compass for referencing my heading

Perhaps you don't sail in areas with significant currents. If you did, you would be well served by monitoring your cmg, for your compass only tells you which way you are pointed, not which way you are actually going. Out at sea where there are no visual clues as to cmg this is especially important IMO and that is where the gps really shines.

And your concern about the time lag in the gps readout... most units nowadays allow you to select the time constant for the smoothing function, so you can set it to a short period and loose the lag. And btw, when in any but smooth waters, even my five inch Ritchie binnacle compass wanders quite a bit with boat motion so the helmsman must do some mental averaging of the readout. A good helmsman can do this easily, but a gps can do it better and without error.

I wouldn't be without a good mag compass, but I steer more by gps these days and. perhaps surprisingly. I've a good track record of arriving on target.

Jim

[SV Windrush II]

Originally Posted by Jim Cate

Perhaps you don't sail in areas with significant currents. If you did, you would be well served by monitoring your cmg, for your compass only tells you which way you are pointed, not which way you are actually going. Out at sea where there are no visual clues as to cmg this is especially important IMO and that is where the gps really shines.

And your concern about the time lag in the gps readout... most units nowadays allow you to select the time constant for the smoothing function, so you can set it to a short period and loose the lag. And btw, when in any but smooth waters, even my five inch Ritchie binnacle compass wanders quite a bit with boat motion so the helmsman must do some mental averaging of the readout. A good helmsman can do this easily, but a gps can do it better and without error.

I wouldn't be without a good mag compass, but I steer more by gps these days and. perhaps surprisingly. I've a good track record of arriving on target.

Jim

Well for the most part I do the same. I always the GPS to Monitor course, if I need to make any corrections I adjust my heading according But still using my compass to steer

[CassidyNZ]

Originally Posted by Training Wheels

Funny, I rarely take the cover off our compass. The chart plotter tells me CMG. I generally steer to that, if I’m on a rhumbline. Usually, we’re steering to the wind, which I want to know our CMG.

Voyaging on the rhumb line is not that great an idea. That’s where big ships live. I make my way left or right of the rhumb line then set a course parallel. Of course if you cruising areas where there are no ships that’s different but a simple fact of life - islands depend on ships for their supplies. Few island destinations are not in shipping lanes.

I don’t use a chart plotter on a passage. I use an old Garmin handheld unit that has one screen that has an arrow pointing at the destination waypoint. That’s all I need to see.

But I still have a steering compass to look at x just for old time’s sake

[CassidyNZ]

Originally Posted by SV Windrush II

The compass is showing real time heading so that I can keep the boat pointed.

Unfortunately since the demise of proper pilotage , a compass actually only tells you where your boat is pointing (as you mentioned). It doesn’t tell you where you’re going.

I was sailing in light airs across the Agulhus Stream (can run at 3kn) off the east coast of Africa. The guy who was “in charge” (another story) insisted that we were going to Madagascar and continually referred me to the steering compass. I finally introduced him to modern thinking and showed him on the GPS that although we were pointing at Madagascar, we were actually headed for a Cape Town

In the days of pilotage, currents were shown on charts and compensated for and leeway was factored in. Don’t believe what you see on your steering compass. When I know I’m on my desired course, I reference the steering compass and whatever it says is what I expect to see next time I look at it. But it doesn’t necessarily tell me where I’m going.

[SV Windrush II]

Originally Posted by Jim Cate

Perhaps you don't sail in areas with significant currents. If you did, you would be well served by monitoring your cmg, for your compass only tells you which way you are pointed, not which way you are actually going. Out at sea where there are no visual clues as to cmg this is especially important IMO and that is where the gps really shines.

And your concern about the time lag in the gps readout... most units nowadays allow you to select the time constant for the smoothing function, so you can set it to a short period and loose the lag. And btw, when in any but smooth waters, even my five inch Ritchie binnacle compass wanders quite a bit with boat motion so the helmsman must do some mental averaging of the readout. A good helmsman can do this easily, but a gps can do it better and without error.

I wouldn't be without a good mag compass, but I steer more by gps these days and. perhaps surprisingly. I've a good track record of arriving on target.

Jim

Well for the most part I do the same. I always check the GPS to Monitor course, if I need to make any corrections I adjust my heading according But still using my compass to steer

Unfortunately I don’t have the latest and greatest electronics, mine are about 10 years old

[CassidyNZ]

Originally Posted by barnakiel

Except that I know how to use all of the toys, much as many hardline gps-only (again!) proponents will be completely lost plotting a plain DR / set / drift line.

Why would I need to plot DR/set/driftline? I can but why would I? My GPS gives me all of that.

DR is “where do I think I am now based on my last known position”. I know exactly where I am. Down to 2 metres accuracy.

X-trac error, etc. is available at any time. There is normally a “highway” on your GPS that you can watch which pictorially updates that info dozens of times in the time that it takes you to calculate it once.

Look, I grew up with charts, sextants, sight reduction tables and all those tools that used to rattle around my nav station. My sextant now resides on a shelf in my mate’s bar as a curiosity. Most visitors ask “What on earth is that?”

Anyone who seriously believes that GPS can suddenly disappear should consider what would happen to other systems using it. Like airliners and commercial shipping. If it is switched off, a lot of people are going to die. Any GPS logs onto up to 12 satellites at any time. If six of them failed simultaneously you would still get a fix 10 times as accurate as with sight reduction. At the very worst, the owners of the constellation (US DoD) may re-introduce selective availability, especially in areas adjacent to war zones. So then your position could be off by 50 metres. But disappear? No chance.

So to say that one iPad (or plotter or handheld GPS) does not represent redundancy to another is wrong. Of course it does. An old adage of traditional navigation was “You never are where you think you are”. Nowadays we all know exactly where we are.

Let’s see charts and associated paraphernalia for what they are - an interesting but onerous pastime.

[El Pinguino]

Hands up all those who can hand steer in fog with reference only to a digital CMG/COG...

[CassidyNZ]

Originally Posted by Simi 60

Plenty of boats do have stern mounted transducers.
I have a small less than $100 transom mount garmin on the big boat as well as an incredibly noisy depth only transducer towards the bow, and a commercial quality fishfinder transducer amidships.

Even our tender has a transom mount transducer.

Am I wrong in believing that depth transducers have to be in the water (thru-hull aside) to work? Most sailing boats have a stern counter that prevents a transom transducer being in the water.

I would really like a decent fish finder but the above belief has prevented me installing one.

[StuM]

Originally Posted by CassidyNZ

At the very worst, the owners of the constellation (US DoD) may re-introduce selective availability, especially in areas adjacent to war zones. So then your position could be off by 50 metres. But disappear? No chance.

If US DOD play around with it, there's still Beidou, Glonass, Galileo ...