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post #1 of 25 Old 09-03-2008 Thread Starter
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Backwards (mis)use of a GPS

I was coming into our home port at night with no moon, just star light.
I knew where I was going and could see the lights for the Chanel entrance. The problem is that there is a unlighted red buoy somewhere up ahead. In normal light even at night it is not a problem but this one is really hard to see.
My navigator put the buoy in as a destination then switched to highway view.
As long as we were NOT on the highway and the distance was a few hundred feet we could forget about it and head for the channel.

Not exactly the way GPS use is taught but it worked.
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post #2 of 25 Old 09-03-2008
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Oopsie!! You want to have your way points on the right side of the channel but not on the buoy itself. And if you are approaching to enter a channel from the side then set your waypoint to between the two reds or the two greens depending on which side you are coming from.
But if you use the exact position of a buoy or a daymark, I guarantee that some foggy day or on a dark evening you will hit the damn thing. Maybe but not today or even a month from now. But you will when your attention is not on safe navigation but on some detail that has attracted your attention for a period long enough for you to hit it.

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post #3 of 25 Old 09-03-2008 Thread Starter
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Quote:
Originally Posted by Boasun View Post
Oopsie!! You want to have your way points on the right side of the channel but not on the buoy itself.

You make a good point of course. I'll set a point off the mark in some cases.
This particular marker is not a channel marker. I guess I simplified things too much. It is actually in front of an island that is in front of the channel.

I know where the island, channel, marks etc are since we sail there several times a week.
I just thought that setting a way point and missing it on purpose was a creative use for a GPS.
Not taking about normal navigation.

As to the idea that setting a point off the mark is safer than setting a point on the mark, I'll defer to folks that know better but:
1. The marks can be off quite a bit from the chart
2. The GPS can be off quite a bit
3. The channel can be moved a bit as dredging is done.
4. The channel can be as narrow as the margin of error for 1 though 3.
5. You can come in at an angle so your course is through the mark to your offset position.
Since 1-5 all are true whatever number you put in the GPS for a mark is likely to cause you hit the mark if you don't have a proper lookout. It is just a matter of time.
So the question is? Is it worth while to put in an off-set mark? I suspect like most things marine, sometimes yes sometimes no.
In either event I suspect a lookout is the best precaution.
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post #4 of 25 Old 09-04-2008
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Last season I saw what looked to be a GPS-guided collision. A commercial lobster boat was leaving New Bedford harbor, and managed to t-bone one of the large green lit buoys along the New Bedford approach channel. They hit it so perfectly that they broke off the front section of their bowsprit, knocked it down and ran over the buoy. It resurfaced under the boat and pushed it aside.

At the time prior to the impact, the bridge was empty...no one to be seen... as soon as they hit, someone showed up and ran across the bridge to the helm.

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post #5 of 25 Old 09-04-2008
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Wasn't that on the Discovery show? I think I remember laughing about that one.

Dictated, but not read.
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post #6 of 25 Old 09-04-2008
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Could have been... the Direction, which was the boat in question, is one that is on the TV show, The Deadliest Catch.

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post #7 of 25 Old 09-04-2008
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Even with GPS switched off, my boat's autohelm has an uncanny affinity for buoys. In their absence, lobster pot markers are its speciality.

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post #8 of 25 Old 09-04-2008
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I would get one of those million-candlepower handheld spotlights. You can see the reflective tape on the buoys a half-mile away. I can't imagine not having one, especially up here in lobster country.

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post #9 of 25 Old 09-04-2008
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Yeah, that spot light is a must! I put in a Garmin 525, bought the chip$$$ and one year later there are new nav aids not on the chart??? So I'll put them in myself. Even the annoying ferries seem to whack the bouys [better them than me] sometimes.

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post #10 of 25 Old 09-04-2008
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Quote:
Originally Posted by ereuter View Post
I would get one of those million-candlepower handheld spotlights. You can see the reflective tape on the buoys a half-mile away. I can't imagine not having one, especially up here in lobster country.
Having tried them many times I can assure you they will destroy your night vision! I still have one on board for emergencies but not for general steaming. If you do use one you really need to get it out over the bow pulpit to avoid any deck reflections. Even then the glare off the water will still kill your night eyes.

I made a stowable "light bar" that I can zip tie to my bow pulpit and plug into my anchor locker. It has four amber colored fog lights mounted to it and it picks up lobster pots very easily. An item like this, or a 1,000,000,000,000,00 gazillion power spot light, should only be used in absolute necessity as it does not meet COLREGS.

Again, 1,000,000 candle power anything will ruin your night vision, which you need!

Just raced last night and sailed back to Portland Harbor in the pitch black. One crew guy brought a LED head lamp with no red lens! Every time he fired that damn thing up I lost lobster pots for a good 60-90 seconds before my eyes recovered. We have banned his headlamp from above deck use for the remainder of the fall series unless he gets a red lens for it...

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Last edited by Maine Sail; 09-04-2008 at 08:35 AM.
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