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Old 08-08-2007, 15:02   #16
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My pref is electronic charts AND paper charts. I compare one to the other and make sure they match. Each 1/2 hour I plot my position on the paper chart just in case. I also use AIS to keep track of the big boats. I use RADAR and ARPA to keep track of everything I can. I don't like ARPA as it can be a bit flakey.
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Old 08-08-2007, 15:20   #17
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I use RADAR and ARPA to keep track of everything I can. I don't like ARPA as it can be a bit flakey.
What's ARPA? Google search turned up nothing related to navigation.
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Old 08-08-2007, 15:31   #18
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Automatic Radar Plotting Aids (ARPA). It is an add on to RADAR and tracks targets and calcs your Closest Point of approach (CPA) and Time to Closest Point of approach (TCPA) etc. If your RADAR is not tuned in well you can end up tracking noise.
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Old 08-08-2007, 15:45   #19
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Thanks, Charles. ARPA sounds like something that could be quite helpful, as long as it works without gumming things up.

Here's an idea based on the way we used to do it in the Navy. Put some kind of protective cover on the radar screen. When a target appears to be tracking with a close CPA, use a grease pencil to mark it with the time. After a few minutes, if both you and the target maintain course and speed reasonably well, you will see a very clear track of the target that can be extended to show CPA, with time.

We also used printed sheets that showed compass points and distances. We would mark the radar bearings and distances, with times. This is the same process as above, but transferred to a paper sheet.

Of course, the simplest thing to do is just note the bearing of the target. If it does not change, you are headed for a collision, so unless you are looking to raft up, better change something!
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Old 08-08-2007, 16:27   #20
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You mean, my chartplotter, radar, gps, depthsounder, autopilot, laptop NMEA networked system won't work?

There's food for thought.
If your boat gets struck by lightening, the chances are excellent that most or all of those toys you listed will become so much recycle fodder. In this case it doesn't matter if you have one GPS, or two, or 64 of them. It doesn't matter if they are turned on or plugged in. They will be toast. Maybe if you put them in a properly designed metal box they will be OK. Maybe.

That is likely not a big deal if you are close to your home port. As I said for local sailing, I am comfortable with e-charts only. But if you are in the middle of a long term, long distance cruise in unfamiliar waters you just might have a problem if you don't carry paper charts and other navigation tools.

But of course it is all a risk/benefit calculation. If you think you are unlikey enough to be struck, and that all your systems are reliable enough to any other common mode failure, then you would be comfortable without the paper charts, or a handbearing compass, or a sextant. You're calculation might also have to do with cruise duration. For a 2 week crusie down the coast of your home country, maybe you're fine. Do you trust all your electronic gear equipment for a 5-year circumnavigation?

I am just not ready to risk my life (and that IS what I think we are talking about here) to the reliability of my electrical and electronic systems. You may be, you may think I am a whining Chicken Little. Maybe I am.

But I'll still buy any paper charts FIRST, then if there are any boat bucks left over I'll buy the electronic versions.

Good Seamanship is all about being expecting and prepared for the UNEXPECTED, you never assume it will not happen.
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Old 08-08-2007, 18:03   #21
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It's very unlikely that a spare portable GPS in a bag and turned of will be fried by a lightning strike.

Paper charts are traditional and some are beautiful.

The electric stack is here to stay.

I have both.
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Old 08-08-2007, 22:02   #22
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i dont have any electronic charts...paper only. Still looking for a good source for used charts. Anyone got any New England they wanna sell?
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Old 08-08-2007, 22:18   #23
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benji - I have some older chartkits that cover all of New England quite well. If you can update them, they should be all you need. When I get back on my boat, I can let you know how old they are and what I would sell them for.
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Old 08-08-2007, 22:28   #24
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It's very unlikely that a spare portable GPS in a bag and turned of will be fried by a lightning strike.
Before you say that with authority, you might want to read some insurance reports about lightning strikes.

The damage does not come down the power wires, but rather is the huge and very rapidly changing magnetic fields associated with the huge currents of the strike. This magnetic flux induces currents in circuit boards that are well above what IC chips can tolerate. Makes no difference if they are turned on or not. Sometime portable stuff survives, sometimes it does not. One sure thing about lightning is that it's effects are very unpredictable.

Some useful first person stories:
Eclipse hit by Lightning
Sail Gemini - Lightning
Lightning strike on the cruising yacht sv Watermelon

And this is the granddaddy of authoritative papers on the subject. Unfortunetly it is getting a little long in the tooth. Here's to hoping that another acedemic type can get funding to update this research from almost 15 years ago.
Lightning protection of boats and marine facilities
According to this research at least 40% of boats struck had ALL of their electronics destroyed.

Bill
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Old 08-08-2007, 23:26   #25
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Having been at sea as a commercial fisherman for 20Yrs and also as a full time cruiser I cant remember when I last put a fix on a paper chart, on our Yacht we use a combination of Computer/Maxsea system and simrad plotter, we print off A4 size chartlets of any Ports or Harbours we may have to get into if we have a system meltdown on a passage and keep them in a folder and chuck them away when we start a new leg, If in doubt about chart accuracy keep a good eye on depthsounder (the most underused navigational tool on most boats) and youn eyes open.
The art of being a good navigator is too use the most accurate method available to fix your position and that aint a sextant these days
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Old 09-08-2007, 00:18   #26
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Intetrestingly, the NZ Cat 1 regs (which all NZ registered yachts must comply with to leave NZ) state that at least 2 GPS units must be carried but a sextant is only a recommendation. Personally, I use paper charts for all passages and only use the plotter (read, free software) as back up very close to shore. Most often I am lazy & plot on the paper directly from handheld GPS but still practice sextant, transits etc. I never rely on GPS exclusively when navigating channels etc. The mark 1 eyeball has served me well over 20+ years.
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Old 09-08-2007, 19:57   #27
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The damage does not come down the power wires, but rather is the huge and very rapidly changing magnetic fields associated with the huge currents of the strike. This magnetic flux induces currents in circuit boards that are well above what IC chips can tolerate. Makes no difference if they are turned on or not. Sometime portable stuff survives, sometimes it does not. One sure thing about lightning is that it's effects are very unpredictable.
Agreed. I have never had a strike but a boat on a mooring 100 meters from mine was struck and sunk. My GPS in the bag was fine.

How many back up systems and types of redundancies are all about risk management. It's a personal choice and in my case would depend on the type of crossings I made.

You can hit large bodies of land from a great distance by ded reckoning. You can miss tiny islands from a short distance as well. Error tolerance is key.

If I was crossing the pacific and had to hit Hawaii I might want alternate means of navigating.

If I am no more than 100 miles off the US coast I wouldn't bother.
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Old 11-09-2007, 16:37   #28
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Now that I can download free, up-to-date, Govt charts, it seems poor seaman practice to use paper. I cruised for 5 years - an ocean and many gulf/coastal crossings plus several trips to and from the Caribbean - here is the drill.

1. I update the electronic charts with the latest notice to mariners prior to departure.

2. I print paper leg charts showing my prime and backup ports of arrival.

3. I post a sailing chart (paper). Mine are 10+ years old - but, after all, continents move slowly.

4. I keep a running log on the paper chart - the computer keeps a log on the electronic chart.

5. I keep a pen/paper log at watch change in a notebook.

6. I have 2 primary and 2 battery GPS and a sextant. I carry only enough material for the sextant to do a noon siting - and have only done one once since I went to GPS.

Seems like belt, suspenders and parachute to me - and yes, I carry a 15' diameter parachute in case it just gets to bad to continue - only used it in practice so far.

Happy sailing /Stu
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Old 05-10-2007, 22:52   #29
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With the utmost respect...

Are you calling the US Navy and Merchant Marine Fleets "foolhardy?" Because they haven't used paper charts for years.

Only recreational sailors use them anymore.
The Navy still uses paper as does the merchant marine. You can't keep an electronic chart current using Notice to Mariners. I got to tour A Los Angeles class sub a few years ago and guess what was sitting on the chart table?...a standard NOAA paper chart.

I keep both on board but use the electronic chart far more often. The advantage to the electronic chart is it is so much faster. At a glance it tells me my current position down to the second and my direction. I also have my auto pilot wired to my computer along with the GPS of course which allows the auto pilot to follow a track line. Paper of course is the required backup and is more current if you keep it updated. That is my biggest frustration with electronic charts...they cannot be kept current.

In my opinion, it's silly these days not to have both onboard.
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Old 06-10-2007, 07:15   #30
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Seamanship

IMHO, navigation, both electronic and with paper charts, is a large percentage of what we call "seamanship." Much of what I love about sailing and cruising is dead reckoning on paper charts. My young boys climb up on the table and study the charts with me. You think that is not a great feeling? They especially like the wrecks.

I don't get a warm and fuzzy from electronic charts at all. Kind of like making bread with a bread machine rather than by hand.

GPS is essential of course, and I use it in conjunction with DR. Still learning celestial - do I consider it essential? Absolutely not. But it is another element of seamanship that I WANT to gain.
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