compass deveiation gremlin

I tend to agree w your comments/perspective, TBG. If you are going in/out of home port on a regular basis - it only takes 1 or 2 trips to write down the magnetic compass bearings off your normal track between buoys/points. That's really all you need to do.

having said that - I don't find it too hard to correct for deviation - and back in the day (now sounding like an old fart) - that's what one had to do since we have only had chartplotters/GPS for the past 20 years or so. before that - you steered by magnetic compass - and you had to get it to line-up with the chart - that is to plot your course to your destination on the chart and then convert back from true bearings - so that your magnetic compass matched.

As tugcaptain and others already stated - you're only off a few degrees (normally) w/o correcting for deviation - but on long distances - that can add-up. I think it's fun figuring this stuff ahead of time. but that's just me...
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TheBigGuy said:
Thanks to everyone for all the informative links. It's all very good information. It would seem to me that creating a custom deviation conversion chart is far more effort than is necessary to navigate short distances safely as long as you take a few precautions. If you are fishing offshore it would seem to me to be far more important to simply record your course and travel times on you first trip out and back. As long as your compass isn't seriously out of whack because of nearby magnetic disturbances on your dash it should be giving a consistent reading. So, the variations and any deviations should at least be consistent when recording your course readings from your compass. As long as you have recorded your course out and back from any area you are fishing, you should safely be able to navigate back without doing complicated conversions while in transit in the fog. That would seem to be more of a stressor than giving you a feeling of security if your GPS goes out in the fog. I certainly would not want to have to do conversions in that situation. I would rather simply want to know the bearing that my compass read to get me back to Port when traveling that route in the past. This requires that you must have made the trip at least once, but you would have to be extremely unlucky to have your GPS go out on your first trip offshore at a new location. Maybe it's just me, but I would rather retrace my course by a known compass reading than have to do any conversions in a high stress situation. Comments.
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I agree that heading back in on your reciprocal headings is not a bad method, as long as the headings out and time/distance travelled at each heading was recorded (or remembered....). You'll be heading back on reciprocal headings anyways if headed back from where you came. However it won't help you much if conditions are demanding a change in destination. You'll still end up having to add or subtract a new course.

I disagree that variation and deviation is a complicated conversion underway.
It's two equations, simple addition or subtraction. A rudimentary understanding of the concept and a little practice. Then it's just a normal part of navigating, and another skill in your toolbox.
 
Thanks for that perspective Tugcaptain, as I hadn't considered severe weather as an added complication to a GPS failure. I guess that's because I just naturally assume when you have foggy conditions the weather is generally pretty calm.

I have been caught by GPS failures several times while on vacation. The Compass and sounder were my life lines to get back to Port. As you stated in your earlier post I could not immediately recognize my location once I'd hit shore, but I could tell by my sounder readings that I was slightly north of my destination. I knew there were no depths that shallow South of my destination, so thereby deduced I had arrived too far north. Luckily I had my wits about me as it was starting to get dark by then and landmarks were not easily identifiable.

Math is my Achilles heel so I've always relied on following a known bearing to return to Port. In a high stress situation I would hate to have my math skills put to the test. I am a very good navigator and would probably not be alive if that weren't the case. Luckily for me I have survived every bad situation I've I've been through on the water. Every tough scrape is a learning experience and the knowledge gained from a lifetime on the water can not be learned from any book. Unfortunately, knowledge about your boats limitations can only be gained by practicing your boat handling skills in severe weather. I'm a little older and wiser now, and I don't tempt fate when there's a dodgy weather forecast anymore. I now do my best to put safety first. No fish is worth risking your life or the lives of your passengers for. When you're younger you tend to think your bullet proof and sometimes make rash decisions. I will now simply forgo an opportunity to fish if the weather could get nasty. I will now overnight, rather that run the strait to get home if things look iffy. When I was younger it was full steam ahead and dam the torpedoes to get to the fish. Very foolish looking back through hindsight, but it certainly made me very capable at handling a boat under the nastiest of conditions.

I hope I will never be unlucky enough to get caught in a storm that forces me to return to a different port from an offshore point with no land for reference with a GPS failure to make matters worse. I don't think I'd ever allow myself to get in that situation now with the better judgment that tends to come with age.

Thank you for pointing out that doing the adjustments for variation and deviation might still be required even if you know your return compass bearings well. You obviously know only too well that being prepared for the worst case scenario could be the difference between life and death. Thank you for pointing out the fact that you can never be too prepared.
 
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What surprises me is that in today’s world people could actually find themselves in a situation where they only have one GPS which has failed in fog or darkness or start with none at all for that matter. I currently have multiple color Chart plotters - two handheld (2x Lowrance Expedition c (color) models which are armoured and water proof) and 2 Lowrance fixed units (although we don’t take them all with us we always have some backup GPS navigation capability as well as a spare ext. antenna.

One of our fixed VHF radios has built in GPS with basic way point navigation although I must confess I have not yet bothered to learn how to put in the way points to get me back to the harbour because of dependence on the multiple Chart Plotters.

On the list of things to buy is a handheld VHF with built in DSC GPS as I like the idea of the coast guard being sent to my precise location if I ever end up in my Santa suit floating in the water while winter fishing. At my age and with my heart, even in the Santa suit I suspect the shock of the cold water would likely stop my heart soon after I hit the water but at least they should be able to find the body quick if I am able to hit the button. (note to self – hit it before you jump in and strap it on the suit up high like cops do so the antenna is out of the water and leave it on 16). I assume the handheld VHF with GPS is also capable of basic way point navigation.

I also plan to add the low cost navigation chart plotter app to my recently purchased slightly used large screen Note 4 cell phone which came with a water resistant armored Otter shell. Total used cost of the phone, armor and the new cost of the app is a little over $300.

With the exception of one of the two Expedition c handheld battery powered color chart plotters and the new fixed VHF with GPS, I bought all this equipment used at very little cost. It is not the newer type high def./resolution equipment but they all do the job of precise navigation extremely well. The new high res equipment in my opinion really only shines on the radar and sounder side of things at substantial additional cost, although at some point I expect we will upgrade.

We also have an older full 25 watt non DSC VHF which we keep vacuum packed on the boat as an emergency backup to the main VHF and is worth about $15.00. In its day it was a high end unit and it is set up to hook right up to the same bracket etc in a few minutes.

I paid $120. used for one of the handheld color chart plotter some years back and it came with extras like a topographical land map chip for hiking, a twelve volt power cord and a Lowrance dash mount slide in and out mounting bracket.

If you look around for bargains and take your time, the older Navionics chart chips can also be found dirt cheap.

The smaller older back up slightly used fixed 5 inch color sounder/chart plotter is worth around $160. now and came with a good spare ext. antenna, transducer and speed sensor, and works with and hooks up to the same plugs as the primary 10 inch unit, should it ever fail, as they use the same antenna, transducer and speed sensor. With a little duct tape it will fit the much larger bracket and be up and running in a few minutes so as not to interrupt the fishing season.

As you can tell I am a bit of a bargain hunter. If we were to take all of it with us, I suspect we would have more navigation redundancy than the space shuttle and at very low cost. So unless the USA, China and Russia start getting belligerent and take out each other’s satellites, or there is a nuclear air burst electromagnetic pulse which burns out most of the electronic devices and computer controlled motors on the coast (in which case we have bigger problems), -- there is really no excuse for being caught out there without precise GPS navigation and backup communication.

When it comes to navigation, we live in a time when you can help insure your survival for very little cash and not have to be white knuckling it back in thick fog with just a compass. I do agree that if you have a compass it is a good idea to know how to install and use it optimally, especially if you are going distance or blue water. In that case you should perhaps know old school navigation in its totality.
 
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Rockfish said:
What surprises me is that in today’s world people could actually find themselves in a situation where they only have one GPS which has failed in fog or darkness or start with none at all for that matter. I currently have multiple color Chart plotters - two handheld (2x Lowrance Expedition c (color) models which are armoured and water proof) and 2 Lowrance fixed units (although we don’t take them all with us we always have some backup GPS navigation capability as well as a spare ext. antenna.

One of our fixed VHF radios has built in GPS with basic way point navigation although I must confess I have not yet bothered to learn how to put in the way points to get me back to the harbour because of dependence on the multiple Chart Plotters.

On the list of things to buy is a handheld VHF with built in DSC GPS as I like the idea of the coast guard being sent to my precise location if I ever end up in my Santa suit floating in the water while winter fishing. At my age and with my heart, even in the Santa suit I suspect the shock of the cold water would likely stop my heart soon after I hit the water but at least they should be able to find the body quick if I am able to hit the button. (note to self – hit it before you jump in and strap it on the suit up high like cops do so the antenna is out of the water and leave it on 16). I assume the handheld VHF with GPS is also capable of basic way point navigation.

I also plan to add the low cost navigation chart plotter app to my recently purchased slightly used large screen Note 4 cell phone which came with a water resistant armored Otter shell. Total used cost of the phone, armor and the new cost of the app is a little over $300.

With the exception of one of the two Expedition c handheld battery powered color chart plotters and the new fixed VHF with GPS, I bought all this equipment used at very little cost. It is not the newer type high def./resolution equipment but they all do the job of precise navigation extremely well. The new high res equipment in my opinion really only shines on the radar and sounder side of things at substantial additional cost, although at some point I expect we will upgrade.

We also have an older full 25 watt non DSC VHF which we keep vacuum packed on the boat as an emergency backup to the main VHF and is worth about $15.00. In its day it was a high end unit and it is set up to hook right up to the same bracket etc in a few minutes.

I paid $120. used for one of the handheld color chart plotter some years back and it came with extras like a topographical land map chip for hiking, a twelve volt power cord and a Lowrance dash mount slide in and out mounting bracket.

If you look around for bargains and take your time, the older Navionics chart chips can also be found dirt cheap.

The smaller older back up slightly used fixed 5 inch color sounder/chart plotter is worth around $160. now and came with a good spare ext. antenna, transducer and speed sensor, and works with and hooks up to the same plugs as the primary 10 inch unit, should it ever fail, as they use the same antenna, transducer and speed sensor. With a little duct tape it will fit the much larger bracket and be up and running in a few minutes so as not to interrupt the fishing season.

As you can tell I am a bit of a bargain hunter. If we were to take all of it with us, I suspect we would have more navigation redundancy than the space shuttle and at very low cost. So unless the USA, China and Russia start getting belligerent and take out each other’s satellites, or there is a nuclear air burst electromagnetic pulse which burns out most of the electronic devices and computer controlled motors on the coast (in which case we have bigger problems), -- there is really no excuse for being caught out there without precise GPS navigation and backup communication.

When it comes to navigation, we live in a time when you can help insure your survival for very little cash and not have to be white knuckling it back in thick fog with just a compass. I do agree that if you have a compass it is a good idea to know how to install and use it optimally, especially if you are going distance or blue water. In that case you should perhaps know old school navigation in its totality.
Click to expand...

The white knuckle ride I was referring to earlier happened quite a few years ago. Cheap backup units were not the norm then, that unit was close to $3000 with charts when I purchased it. Not quite the same then as today for redundancy options. I also have several other gps aboard for backups nowadays because you just never know when the unexpected will happen.. Your boat could have a complete electrical failure, and handhelds batteries die. You could be left with no electronics and only your kicker for power. While highly unlikely, the whole sat system could go down. The Americans have shut the nav data from the sats down before. One nuke detonated in space might tend to disrupt things a bit too (hopefully that day never comes). I imagine a coronal mass ejection from the sun might also leave us without communications for a good while. Never say never, because the unimaginable sometimes happens.

A compass always serves a purpose on a boat in my opinion regardless of how much technology you have aboard. For some reason I just find it easier at trolling speeds to steer by a compass in the fog. When trolling slowly in the fog I've sometimes found my GPS has a hard time determining my direction of travel and loses its lock. To me there's always a need for a compass aboard, and the knowledge to use it. Otherwise it's kind of like saying we all have central heating, so who needs to start a fire. Guess what I always have a lighter aboard with me too. Never know when I might have to beach the boat and start a fire for survival.
 
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Sorry Big Guy it was not my intent to take a shot at you personally on not being prepared but was speaking in generalities to point out for example that even if someone is on a serious financial budget and fishing a 12 foot tinny on perfect flat days without a charging system, that you can still get older handheld color chart plotters and VHFs for very low cost including backups. You never know when the fog can come in fast.

For some reason I take a bizarre pride in my frugalness on electronics yet waste money on things like expensive Islander reels which are not really that much better than my Shimano. Hum, o-well I am too old for therapy.

I can't recall that I have ever lost GPS tracking in the fog with the main GPS unit with the external antenna. I hope that does not happen often to you.

I agree with you on the value of a physical compass, that's why I have two set up so as not to cause mutual interference that are very accurate with no gremlin problems and which always agree with each other.

Next summer when I am back on the boat I will again write down the heading for each compass and also the heading on the primary GPS true north compass rose for comparison. Interestingly as I recall, the lat. and long which displays on the VHF with built in GPS and has an internal antenna in the cabin is almost always the same as the lat and long on the main Chart Plotter which has an external antenna. When they are off it is by a very small amount. Surprising and just lucky I guess. Thinking about it now, perhaps it may not be a bad idea to get myself a paper chart for the area I spend most of my fishing time in. That would be useful if for some remotely unlikely situation I was ever having to GPS waypoint navigate (no E Plotter) by being able to look up lat and long on the physical chart to confirm where I actually am and be able to look up and have a physical representation of where the various waypoints are located on the physical chart. I have never done that (we did not have GPS back in the day) and have not looked at a paper chart for decades so not sure how well it would work in practice, but if so it would be one more useful tool. If I try that I suspect it would be best to give it a try when it is not foggy to see how well it works, like practicing with your radar in clear weather.


Cheers

Rocky
 
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All good Rockfish. I am true old school, and do carry paper charts for any area I travel to from my home waters. Paper charts are way better in my opinion for figuring out good locations to bottom fish. You can look at a much wider area than on the small screen and get a better visual grasp of current patterns in an area with lots of islands. At least that's what I think, but good luck trying to convince most people of the value in actually carring paper charts these days.
 
agentaqua said:
My understanding is that legally - we still need paper charts onboard.
Click to expand...
That is true, but how many people actually carry them these days? Not a lot, I'm guessing (outside of the large coastal cruiser type vessels) .
 
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agentaqua said:
My understanding is that legally - we still need paper charts onboard. Good discussion on that at: http://www.sportfishingbc.com/forum/index.php?posts/779018/
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That's not true. From the link in the post to which you refer to: (Note emphasis bold and underlined added by me, comments added in Red).


  • (2) The master and owner of a ship of less than 100 tons are not required to have on board the charts, documents and publications referred to in subsection (1) if the person in charge of navigation has sufficient knowledge of the following information, such that safe and efficient navigation in the area where the ship is to be navigated is not compromised:

    • (a) the location and character of charted
      • (i) shipping routes,

      • (ii) lights, buoys and marks, and

      • (iii) navigational hazards; and
    • (b) the prevailing navigational conditions, taking into account such factors as tides, currents, ice and weather patterns.
Note: So in brief recreational boaters are not required to carry paper charts if you know enough about the area. All of the above can be accomplished with a good chart plotter with an appropriate electronic map - e.g. all of those features are marked on anything other than the base map of most modern chart plotters.
  • (3) If a ship, other than a pleasure craft of less than 150 tons, is making a foreign voyage, a home-trade voyage, Class I, II or III, or an inland voyage, Class I, the master and the owner of the ship shall have on board and make readily available to the person in charge of the navigation of the ship an illustrated table of life-saving signals for use by ships and persons in distress when communicating with life-saving stations, maritime rescue units or aircraft engaged in search and rescue operations.

  • (4) If a Canadian ship is of 150 tons or more, the master and the owner of the ship shall have on board and make readily available to the person in charge of the navigation of the ship the International Aeronautical and Maritime Search and Rescue Manual, Volume III, Mobile Facilities, published by the IMO.
  • SOR/2005-135, s. 2.
Use of Charts
  • 5 (1) Subject to subsection (2), in order to plan and display a ship’s route for an intended voyage and to plot and monitor positions throughout the voyage, the person in charge of the navigation of the ship shall use the most recent edition of a chart that
    • (a) is issued officially by or on the authority of
      • (i) the Canadian Hydrographic Service, when the ship is in Canadian waters, and

      • (ii) the Canadian Hydrographic Service or the government or an authorized hydrographic office or other relevant government institution of a country other than Canada, when the ship is outside Canadian waters;
    • (b) applies to the immediate area in which the ship is being navigated; and

    • (c) is, for that area,
      • (i) the largest scale chart according to the reference catalogue, or

      • (ii) of a scale that is at least 75 per cent of the scale of the chart referred to in subparagraph (i) and is as complete, accurate, intelligible and up-to-date as that chart.
  • (2) The person in charge of the navigation of a ship may use the most recent edition of a chart that is the second-largest scale chart for an area according to the reference catalogue where
    • (a) the scale of the chart is at least 1:400,000 (2.16 nautical miles to the centimetre); and

    • (b) the ship is
      • (i) more than five nautical miles from any charted feature or charted depth of water that represents a potential hazard to the ship, or

      • (ii) within an area for which the largest scale chart, according to the reference catalogue, is primarily
        • (A) a chart intended for the use of pleasure craft, or

        • (B) a chart of an anchorage, a river or a harbour that the ship will not transit or enter.
  • (3) The chart may be in electronic form only if
    • (a) it is displayed on an ECDIS or, in the case of failure of the ECDIS, on a back-up arrangement; and (Note: ECDIS = Electronic Chart Display and Information System = Chart plotter)
    • (b) the ECDIS
      • (i) in waters for which an ENC is available, is operated using the ENC, (Note: ENC= Electronic Navigational Charts= Vector chart)
      • (ii) in waters for which an ENC is not available, is operated using an RNC, (Note : RNC = Raster Navigational Charts = a scanned image of an official chart)
      • (iii) when the ECDIS is operating in the RCDS mode, is used in conjunction with paper charts that meet the requirements of subsections (1) and (2), and (Note: RCDS = Raster Chart Display System)
      • (iv) is accompanied by a back-up arrangement. (Note: The above sections let even commercial boats use ENC charts on a chart plotter if they have a backup arrangment)
The same is true in the US. Like Rockfish, I have two independent, fixed mount chart plotters on board. I have additional backup in the form of Navionics on a battery powered iPad AND on my battery powered iPhone. In addition, I have a battery operated Garmin GPS in my ditch bag and my buddy typically is on board with Navionics on his phone. If I have my laptop on board, I will also have a copy of all the ENC and raster charts for the area on it. I haven't purchased or carried a proper paper chart for years. It's not needed. I have the equivalent in multiple forms and in a few forms that are independently powered from the boat's power system.
 
Hey Seadna, sorry to nitpick, but if you're going to get technical while quoting law.....
ECDIS does mean what you say it does, but it does not "=chart plotter". They are two different things. They serve the same function, but to be considered ECDIS there are strict international compliance regulations that chart plotters do not meet. If a commercial vessel has good working ECDIS systems that haven't been updated (by paying expensive yearly fees), it must carry charts even though it's two ECDIS systems are still functioning.

I've often wondered how Transport Canada would judge "sufficient knowledge" of the area. I've never heard of someone defending their local knowledge after being "caught" without charts. I've also rarely run into a transport Canada employee who has much local knowledge themselves. Most folks who have been around some and have studied many areas thoroughly, would still be hard pressed to look out the window and tell you whether they were in the traffic lane, or in the separation zone, or on the edge, or just outside.....
Thank goodness for electronics, and charts :)
 
Tugcapitan said:
Hey Seadna, sorry to nitpick, but if you're going to get technical while quoting law.....
ECDIS does mean what you say it does, but it does not "=chart plotter". They are two different things. They serve the same function, but to be considered ECDIS there are strict international compliance regulations that chart plotters do not meet. If a commercial vessel has good working ECDIS systems that haven't been updated (by paying expensive yearly fees), it must carry charts even though it's two ECDIS systems are still functioning.

I've often wondered how Transport Canada would judge "sufficient knowledge" of the area. I've never heard of someone defending their local knowledge after being "caught" without charts. I've also rarely run into a transport Canada employee who has much local knowledge themselves. Most folks who have been around some and have studied many areas thoroughly, would still be hard pressed to look out the window and tell you whether they were in the traffic lane, or in the separation zone, or on the edge, or just outside.....
Thank goodness for electronics, and charts :)
Click to expand...
You are of course, correct in that ECDIS is a specialized chart plotter that has to meet specific regulations in order to be certified (and which has to be kept up to date). My primary point is that even commercial guys don't have to carry paper charts if they have good electronic systems in place (and have a backup).

As for sufficient knowledge of the area, my belief is that having good charts on the chart plotter and having studied them prior to one's journey would likely meet the standard as all the features of concern are marked on a good chart in the chart plotter. I agree that "Most folks who have been around some and have studied many areas thoroughly, would still be hard pressed to look out the window and tell you whether they were in the traffic lane, or in the separation zone, or on the edge, or just outside.....". In fact most folks can't do that with a paper chart or if they can, the can't do it very quickly. But on a good chart plotter, one glance and I can tell you that instantly. Pretty much anyone who fishes Swiftsure (especially in the frequent fog), is FAR better off with a good chart plottter (and radar) than with a paper chart if they want to stay out of the shipping lanes. That said, I've seen plenty of guys who don't stay out of the shipping lanes while fishing there and who occasionally need to be "reminded" of their responsibilities by the US or Canadian Coasties.
 
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