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Sailing and GPS-report


Knut

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Sunday 30 March was a bit rougher than normal on Biscayne bay. With standard jib and no reef in the main it was like riding a bycycle in strong gusty wind and frequently the main sheet had to run out freely when the hard gusts hit. Quite an exercize because of a "cold" front coming in. Out on Elliott Key a family in a powerboat (that lost power) got the boat swamped and tragedy struck. The two youngest kids did not make it.

Today, the weather forecast said 10-15 mph and I received a new GPS yesterday, but had no time to really learn too much. Still, the intention was to get some good measurement on boat speed, for the fun of it. The wind turned out to be lousy, so we only got up to 4 mph and most of the time from 2 to 3.5 but the GPS turned out better than expected. We made 8.29 miles from the marina channel opening and back, based on the GPS-registered actual track. I uploaded the track to the PC and made a JPG-file of it, just to give an impression (see attached).

The gadget will become very useful when going to new areas. Handling charts and navigation tools with one hand on the wheel and the other hand with the mainsheet does not work well. With this handheld (and a little bit pre-planning on the PC, it is all a different ballgame. The GPS has also a compass, so I will probably not mount a fixed boat compass. We will see after some more practical experience with the new "toy". :D:D

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Very cool, Knut! I've been meaning to get a GPS to track my speed. My impression has been that the Weekender will go about 5 - 6 knots in a stiff breeze, but not much more than that. But that's only a gut feeling, not anything I've ever measured.

Anyone else get a speed reading on a GPS in their Vacationer or Weekender?

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Knut,

I really haven't started shopping for the gadgets yet, but does the software come with the GPS or is it a seperate item you bought?

Also, what is the brand of the GPS unit/software?

I like that you can view your course after the fact. Is it recording positions on a timed basis or per your input for position?

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I am, may be, not the right guy to give feedback on this subject. I never had a handheld GPS before and I have only used the stationary systems in larger boats. On top of that, I have only had it out on the water once! More reporting will follow later when I have a little more experience and I am NOT recommending anything to anybody, because the needs are so different. To the specific questions:

Garmin GPSmap76S: Software and cable (serial port) to communicate with the PC is included. It also has a basic land-map of the US pre-installed. It can be operated by one hand (using the thumb on the keyes) like a cellphone. The screen is of course small, but by using a multitude of zoom-levels you can switch from overview to detail as needed. It is watertight and it floats.

I bought separately a so-called BlueChart CD (marine maps). This one covers the Americas, but you only get the un-lock code for one area in the 140$ paid. (Additional areas un-lock codes cost 90$ as far as I recall). The single area is more than enough for me, covering almost all of Florida with the Keyes out to the Tortugas + the Bahamas etc. From the CD any map you need can be transferred to the GPS-unit memory. With 24 MP capacity it seems more than adequate.

The tracking of a trip can be started from any point you like onwards. The unit shows a bread-crumb track on the screen as you go. This is the one I uploaded to the PC. After the trip you can even get your average speed, maximum speed etc etc. Of course you can choose metric, statute, nautical miles etc and speed in mph, knots etc. I am quite impressed with the whole thing.

Hopefully I learn the toy better as I go, but it is quite intuitive it seems. More reporting later; watch this space!

:D:D

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Thanks for the info Knut. I realize each one is probably different in its features and the same with the software, but its a good starting point to begin researching with.

We have many little islands and coves in the Puget Sound here and to have the ability to go back after the fact and plot where I may have wondered around would be interesting.

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Hi,

I certainly expected the warnings about not relying on the GPS alone (since I did not say anything about it).

I agree completely, but it does not change the fact that as long as the GPS works properly and you have batteries etc, it is so much more practical in a small boat like the Weekender. Regarding reliability: One guy had used this same type GPS open on top of his cayak for a real long paddle trip in the Everglades, 3 weeks or so. Worked perfect all the time. Certainly, I will in any case bring water-safe "paper" maps and a pocket magnetic compass of good quality (Silva with mirror for straight arm reading of bearings and courses). A fixed boat compass; maybe, but the trouble is to find a good spot for it without limiting sitting space and comfort. We will see, decision can always be postponed until it solves itself one or the other way.

I can also see that I will like very much the option to make colour map prints on the PC, tailor cut to my particular needs for special approaches etc. If you need to re-use, they can even be easily laminated and no fear of damage or wearing out. Just make a new one if needed.

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Knut,

I strongly agree with Ray. Install a compass, a lighted compass.

When you really, really need it, you might not have a hand free to check the GPS, especially at night.

It's much easier to maintain a course with a compass mounted in front of you than continually checking the GPS. On my Silhouette I had the compass mounted on the vertical bulkhead of the bridge deck. Another place you might consider would be on the cabin bulkhead next to the companionway.

All that said, a GPS is wonderful!

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Hi, everyone. I am curious about gps. I learned piloting and charts ect. from the usps. Some of the guys that were instructing the class had many years of experience under there belt. I have heard other guys talking about there experience with it sitting in the harbor and getting goofy positions from a half mile inland to two miles offshore. I have also heard that the government can degrade this signal accuracy at there whim? If you want spot on accuracy you can subscribe to a better signal service for a fee of course. Are any of these true? what has been your experience? I agree with ray that you should have a good compass and a set of charts for your area also may I add that you have the compass swung or adjusted by a certified professional. this just may save your life and your crews life sometime. May I also add that you get some training with the united states power squadron or coast guard although I don't have any experience with the later.

Thank you, Captain red 8)

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Thanks for all the well meant advise. I may repeat that yes, paper maps and magnetic compass clearly have to be available and yes, I do know how to use them both on land and sea (which of course is necessary for the tools to be of any use at all). However, it seems like we are sometimes writing about the same things but from quite different angles.

My angle is a very small Weekender that I intend to use for pleasure sailing in broad daylight only (when over-nighting, no sailing in the dark, just an anchor light or the boat beached) and basically in the ICW from Miami down into the Florida Keyes. It goes without saying that any trips to the ocean side of the keyes and reefs will only be occasional. Fog and dark can never be totally excluded, but reliable light sources are available and belong to the equipment and can be used if necessary.

Lighted and fixed bulkhead compass require power, makes a hump in a bulkhead that is very nice to lean a back against (when it is clean) and for this kind of sailing, I actually prefer the mentioned Silva-type compass because of the flexibility in making long sights and for establishing position by cross bearing plots. This is not preventing me from looking for a fixed compass type that can be made to fit my cockpit and if I find a really good solution I will also install it, but not in replacement of the Silva.

GPS signals as we receive them for public use are actually always a little degraded compared to military use (if I have understood this correctly). The position accuracy is normally less than 49 feet and if support stations on ground are available the accuracy may be down to 10 feet. In any case good enough for my purpose and without having checked carefully yet, the accuracy seems to be the 49 feet or better.

Stories about GPS-measured positions plotting on the rocks (when you are actually on water) and opposite, are probably true but sometimes a matter of old and not so accurate maps, but as always, check and double check when things are critical, as you would do also with ordinary navigation tools. As it looks to me today, the GPS and the PC-planning of routes for transfer to the GPS, is going to be my tools for navigation and back-ups will be available. It will be interesting to see if my expectations will be met. :D :?:

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Guest Anonymous

Course being Downeast Maine, fog is an ever present threat that can descend with alarming speed.

Your plan does sound sound though.

G.P.S. is good but be aware of the limitations they present. When new selective availability was far more an issue than since when Pres. Clinton eliminated it. One thing this serious conservative can applaud him on.

Usually, the signal now locates you far more precisely and exactly than the obstructions on the chart are located. Many charts have been written 40 years or more ago. The obstructions charted were not charted with the benefit of GPS.

Be aware and still give danger areas a wide berth just as if you wern't exactly sure where on this earth you are.

Ray Frechette

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Hi, I would like to throw in a couple of remarks because some replies set m thinking a little:

Ray stated the following:

"Course being Downeast Maine, fog is an ever present threat that can descend with alarming speed."

And from someone else who did like (or prefer?) dead reckoning.

Let us agree that we have agreed that a GPS should not be relied upon as the only navigation tool on board. There is no discussion about that. However, I get the strong feeling that the message I hear is something like: When the going gets tough..... then forget about GPS (because it can fail/malfunction/run out of battery/ fall in the water etc). I am very much tempted to look at the flipside of the coin. The last units even handhelds are now very reliable and accurate. If for any reason there is a problem with sattelite contacts, the unit will beep an alarm and display such message. Also under normal operation it will calculate the position accuracy and display it. Running out of batteries (is like running out of fuel in a powerboat; some people will always be able to, but it is not a fault of the equipment) is totally unnecessary. The same people will also forget to bring the maps in the first place.

So, what I am saying is (from the small cockpit of a Weekender), that in dense fog, pitch dark night and other difficult conditions, I would no doubt use the GPS as my primary tool, combined with a compass as long as the equipment works properly and keep paper-map and other tools handy and updated on the situation just in case. When it is NOT working properly, the unit will tell you and in any case, by doubling up with traditional tools, you should be able to detect that.

My point is that when you get in your hands a gadget that is so accurate and practical to work with and reliable, especially in difficult conditions, then I prefer to also see the positive side of it and take full advantage. In real rough weather I already see that the GPS can be easily operated in the Weekender cockpit (while at the helm), while papermaps and rulers and pens will quickly become more than difficult.

An added point to the discussion: A Weekender is a sailboat and I have only a 2.5 hp outboard for zero wind and tight spots. If the problem would be strong wind, waves, delay, fog and/or dark I might have to advance by sail in any case. Dead reckoning with the side-drift, currents etc. is much more of an unknown in such a small sailboat than in a powerboat. Especially if beating against the wind in areas requiring frequent tacking. Again, the GPS is a real solution and it outperforms anything else (and I am NOT forgetting that it may fail).

Did I throw some fuel into the discussion?? If so, fine; after all it is about "messing-about in boats" or not?

:D:D:D [/b]

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Hi, Knut. I didn't mean to sound like an alarmist or such. I have no experience with gps. You're right it's a good thing to have along with everything else that is available to us. Throw in a good dose of common sense go out and have a good time. Thats all anyone of us can do anyway, beyond that it's fate can't stop that. Hows the weather down there are you able to get out during the week or only on weekends? Well knut you have a good day and I hope you have good conditions next time you sail!

Sincerely, Captain red

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I've been sailing with an old Garmin 48 for a good while now and I have found it to be very accurate. To the point where when it says look out and you still can't see the marker then you need to go see an eye doctor cause you're about to hit it. If fog or rain is so bad to where you can't follow GPS then you should have been off the water a long time ago.

Newer GPS units are waterproof to be able to survive a complete dunking and I would never, ever use it without taking spare batteries along. Selective dithering wasn't turned on for the Iraqi war so I really don't forsee it being turned on anytime in the near future.

Where Knut and I live it's really a no-brainer. If you're out at sea and you get totally lost, the GPS fails, your paper charts blow overboard and the fluid drains out of your compass. Then simply head west by figuring from the sun. Trust me, you'll hit land.

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Ok I can agree that a GPS out does dead reckoning in the fog, :idea: but radar does even better. :D I have lost all power and though I now have a hand held GPS at the time if I had not kept my charts up I would have been in trouble. GPS is great, remember at a time of war it can be reset to show deviations. Not all ports or is every GPS setup with Deferential. Depending on any one system can get you in trouble. The best days can end up in fog. :roll:

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Guest Anonymous

No, I don't throw out the GPS when the fog rolls in. I do however want backup in the form of compass and charts in case the GPS fails due to equoipment malfunction or battery failure. I also would check GPS against expected compass course as well and if in Fog there was a significant variance it would give me cause to pause and to recheck inoutted waypoint and not simply blindly trust the gps over compas and chart.

As long as GPS is working it is my primary nav tool. Not the only one though.

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Guest Anonymous

Where Knut and I live it's really a no-brainer. If you're out at sea and you get totally lost' date=' the GPS fails, your paper charts blow overboard and the fluid drains out of your compass. Then simply head west by figuring from the sun. Trust me, you'll hit land.[/quote']

The trick is to make sure that you hit land in a controlled manner so as to not do damage to equipment and or crew.

Keep a 50 lb sack o potatos on board so that in fog you ken chuck one every 3-4 minutes and make sure you here a splash.

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