I rarely need a GPS for kayaking. But I like gadgets. I used to wish for fog so I could use my unit, but it was rarely foggy enough that I really needed it. Usually, sounds and sights in the fog were enough for me to make my way with a standard chart. I had an old unit with a very primitive map and no real chart. It was good enough for telling me how fast I was going and telling me how far I had to go etc. Last summer, I bought the Garmin 60 X with the chart because I was semi-leading a group and felt an extra-level of responsibility. I thought it would be overkill and sort of ridiculous with the little chart, but on a one week trip off the west coast of Vancouver it was useful twice. One day we had a REALLY thick fog. In 25 years of paddling that coast I have run into fog this dense only one time previously. It was nice to be able to take a course that kept you in deep enough water to avoid the reefs and yet avoid going ridiculously far off-shore. You could still hear the surf on the beaches so you could remain oriented in that way but it was useful to know how far away from the coast to paddle to avoid incidental rocks. Another day, it kicked up and we wanted to get off the water to a beach that was sheltered by a complex pattern of reefs. I have found that often, when you are standing on a beach, it is usually easy to plot a course out to the deep water, but when you are out in the deep water, it can be hard to plot a course back in. From the water, you often just see lines of overlapping breaking waves. It is hard to make out which ones are close and which are far so often it looks like there is no easy way in. With any chart, you can see that there probably is a route that is free of rocks and a route that is relatively deep so that you do not anticipate breaking waves. But it can be hard to tell exactly where you are. Using Garmin with built-in chart, it was great. I could just steer my way in and minimize the chance I would get caught by a sneaker. You are assuming that the chart is accurate and they generally are. But you have to recognize that if you are relying on every rock to be within 100 feet of where the GPS would put it that you might run into an area that the map makers were in error. These are not regions that commercial traffic is very interested in. So you have to stay alert. Anyway, these two experiences really made me happy that I had the GPS with the "real" chart. *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Robert Livingston wrote: > You are assuming that the chart is accurate and they generally are. But > you have to recognize that if you are relying on every rock to be within > 100 feet of where the GPS would put it that you might run into an area > that the map makers were in error. These are not regions that commercial > traffic is very interested in. So you have to stay alert. I'd like to reinforce this. One day, while gunkholing its shore, I found several near-surface underwater rocks just off Gibraltor Island, in the Broken Group, Vancouver Island, which were mis-charted by 100 feet or more. Not an issue for me that day, but a good caveat for future dependency on a GPS. Better to mainly depend on your eyes, and glance at the GPS now and then to confirm what you see, or to see if there is a hidden rock in the vicinity. Robert's description of using his GPS to route-find through a reef maze to a safe harbor was a telling illustration, also, of the value of a unit. I'd want a chart on deck, too, in case the thing cratered mid-passage, so I could patch my way through the old way. I really like charts, and enjoy matching what is on the chart to what I see. For me, the GPS is mostly a tool. Some days, I leave it home, to get away from looking at that blame screen! -- Dave Kruger Astoria, OR *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
<snip> > > Robert's description of using his GPS to route-find through a reef maze to > a safe harbor was a telling illustration, also, of the value of a unit. > I'd want a chart on deck, too, in case the thing cratered mid-passage, so I > could patch my way through the old way. I really like charts, and enjoy > matching what is on the chart to what I see. For me, the GPS is mostly a > tool. Some days, I leave it home, to get away from looking at that blame > screen! > > -- > Dave Kruger > Astoria, OR My wife is firmly convinced that the world is inevitably moving to a future where all we do is stare at small screens. Cell phones, digital cameras, computers, digital audio players, TVs: they take up an enormous amount of our days. Add a GPS to the mix and it's really starting to add up! Of course, our family is a hold-out in a world of larger and larger TV screens, so maybe the future isn't necessary starring at _small_ screens, just starring at one or another type of screen. -- Darryl (Mandatory paddling content: I prefer charts to a GPS too, and not only because I need glasses for reading and I can't make out a GPS screen without them. Whereas I can make out a chart -- vaguely.) *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
The "Lighthouse Lakes Kayak Trail" established by Texas Parks & Wildlife (TPWD) is on a large shallow bay system in the Gulf of Mexico N. of Corpus Christi. There are excellent maps and overhead aerial photos and the light house (not functioning but the largest structure for miles) is nearly always available for a point of reference. TPWD has put navigation poles with numbers that can be referenced to those maps which also have associated GPS coordinates. On a good visibility day navigtion among the small islands with dense vegitation is difficult. In a fog, its nearly impossible and GPS can really be a lifesaver. Also after a long paddle and needing to fight the wind on the way home I am glad to have it. For what its worth, I have a 5+ year old B&W Lowrance IFinder that still does some things better than any of the new Garmins I am looking at. It once also sat at the bottom of the Devil's River for some time. After I literaly poured water out of it and thought it was a goner, I took it apart and laid it on a rock for several hours and put it back together. It made a come back and has served me well for 2 years since. *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
It's not just GPS units that have errors in the positions of rocks, etc. Regular charts have them too; in fact it's likely that the navigation charts on GPS units just transferred the errors over from the published charts when they digitized them. When we were using sextants we seldom noticed these errors; or at least I never did. Even with the original electronic navigation systems (Omega, Loran-A and -C and Transit Satellite) nothing was really accurate to the degree that we could demonstrate that a chart had errors unless we were a hydrographic survey vessel; we just had other things to do. But in the past 20 years, since the advent of GPS, I've found several instances of chart error. It's probably much more evident now with the deliberate errors turned off. Admiralty charts were no less immune to these errors than US charts and some charts from third-world countries (Mexico is one) were - contrary to popular legend - much better than both US and UK charts. Which reminds me to advise everyone that the Mexican tide tables for the Sea of Cortez are (or, at least, were) much more accurate than those published in the USA for that region. So I suspect that until all charts have been re-surveyed using modern techniques (not likely in my lifetime) we should all be very careful of assuming that the chart on our GPS or chart table or kayak deck is absolutely accurate. As an aside; it's interesting to note that GPS satellites have to take into account the relativistic effects of time dilation in order to give us accurate positions. I never thought about this until I watched a program about Albert Einstein over the weekend. Yet more evidence that Professor Einstein's "thought experiments" worked very well. Craig Jungers Royal City, WA On 1/1/07, Dave Kruger <kdruger_at_pacifier.com> wrote: > > Robert Livingston wrote: > > > You are assuming that the chart is accurate and they generally are. But > > you have to recognize that if you are relying on every rock to be within > > 100 feet of where the GPS would put it that you might run into an area > > that the map makers were in error. These are not regions that commercial > > traffic is very interested in. So you have to stay alert. > > I'd like to reinforce this. One day, while gunkholing its shore, I found > several near-surface underwater rocks just off Gibraltor Island, in the > Broken Group, Vancouver Island, which were mis-charted by 100 feet or > more. > Not an issue for me that day, but a good caveat for future dependency on > > a GPS. Better to mainly depend on your eyes, and glance at the GPS now > and > then to confirm what you see, or to see if there is a hidden rock in the > vicinity. > > Robert's description of using his GPS to route-find through a reef maze to > > a safe harbor was a telling illustration, also, of the value of a unit. > I'd want a chart on deck, too, in case the thing cratered mid-passage, so > I > could patch my way through the old way. I really like charts, and enjoy > matching what is on the chart to what I see. For me, the GPS is mostly a > tool. Some days, I leave it home, to get away from looking at that blame > screen! *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
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