Is the magnetic compass becoming irrelevant?

[blackdogsailing]

I would never want to lose it entirely. like other posters I do use it to set up a course on a cross channel or ocean passage, or to give the helmsman a course to steer. However, one thing I have done away with is the need to get it accurately swung by a compass adjuster. A deviation card made from the hand bearing compass is all you need now i think.
how many here have taken bearings of the sun at sunrise/sunset to obtain a deviation ? (Amplitude i think it was called but please correct me if wrong)

Chris

 

[oldbilbo]

I would never want to lose it entirely. like other posters I do use it to set up a course on a cross channel or ocean passage, or to give the helmsman a course to steer. However, one thing I have done away with is the need to get it accurately swung by a compass adjuster. A deviation card made from the hand bearing compass is all you need now i think.
how many here have taken bearings of the sun at sunrise/sunset to obtain a deviation ? (Amplitude i think it was called but please correct me if wrong)

Chris

I'm one.... and the 'sun's amplitude' is the true bearing of the sun at rising/setting, as defined. There are tables available for this and, of course, there are 'amplitudes' for the rising/setting of all other Heavenly Bodies, should they be needed. It's an 'Ocean' thing that all 0/Yotmeisters are expected to be able to do.

In days when oceanic Deduced Reckoning was the primary navigation technique, monitored by such astro fixes as/when could be found, then the importance of checking - frequently - the accuracy or otherwise of one's Main Steering Compass was paramount.

I - and all navs of my vintage - were trained to check and keep Checking By Comparison the main and other compasses on board. The main idea was to get an early 'heads up' in the occasional ( but not rare ) event of something going adrift. The consequences of 'not noticing' could be and were severe, on an aircraft with limited fuel and even more limited places where one could alight painlessly.

I'm still a bit underwhelmed by the culture of not bothering to do the most rudimentary checks on compass effectiveness, to say nowt about accuracy. I believe it's an RYA thing, caused by most of their exalted Training Department being superannuated dinghy sailors with superannuated dinghy attitudes.

Me? My habit is to compare the available compasses and, if there's a substantial difference, move the boxes of beer cans and spanners to somewhere else.....

 

[Bobc]

Your GPS will give you COG and a fluxgate will give you CTS, and that's pretty-much all I use these days.

I think that if I had to spend a big dollop of money to replace them, I'd think seriously about just having something as an emergency backup (a hand-bearing compass and a handheld GPS should do it)

 

[Ric]

A compass is also a useful tool for calculating how much leeway you are making when used in conjunction with a COG on a GPS. Helps you decide which is the best making tack. It also helps you work out whether it is time to tack or not to make it around that headland just over there.

I wouldn't be without one. I bought an electronic compass from NASA but as it sometimes tells me I'm going south when in fact I'm going north I wouldn't put much trust in it!

I think you and some others are missing the original point I made - the Raymarine electronic compass view does everything you mention, plus wind, tide, leeway are overlaid over the compass rose. Also, it does not swing about in a heavy sea, is not subject to acceleration/deceleration swings, does not need rose counterweights so works equally well in both hemispheres, and measures a true bearing rather than magnetic so you can use it even in higher latitudes.

 

[AntarcticPilot]

I have both fluxgate and card compasses. Of course, they both measure the same thing, and usually I am quite happy with the output from the fluxgate compass. The fluxgate compass has several useful characteristics, not least being that it can be calibrated automagically! But its integration with the rest of the instrument suite is also very useful.

BUT! The fluxgate compass a) depends on an electricity supply, b) could be knocked out by a failure in another piece of kit (it's on a SeaTalk bus) and c) is mounted low down in the hull, so if there was flooding, it could be damaged by water. In those cases I'd be VERY glad that I still have a large, clear bulk-head mounted Sestrel steering compass!

 

[KellysEye]

>I can see a time when it will be irrelevant and yachts will be sold without them, just electronic systems and paper charts will go the same way too.

I doubt that will happen. Electronic kit can break and batteries can go flat. I would always have a compass never bothered with a chart plotter, a waste money and has the problems mentioned, and used charts.

 

[jerrytug]

I think you and some others are missing the original point I made - the Raymarine electronic compass view does everything you mention, plus wind, tide, leeway are overlaid over the compass rose. Also, it does not swing about in a heavy sea, is not subject to acceleration/deceleration swings, does not need rose counterweights so works equally well in both hemispheres, and measures a true bearing rather than magnetic so you can use it even in higher latitudes.

A true bearing, how does it manage that when it is still subject to variation?
I know you are meant to be able to teach it your deviation by motoring in a circle, although wouldn't it still need checking with a hand-bearer?
I have been on at least two yachts with fluxgate-compass controlled autopilots, and seen the autopilot hurl us off course when someone below switched on a bunk light or something, so forgive the distrust!

 

[Birdseye]

The magnetic compass at the wheel of my boat needs replacing. The cost of a new one is not far short of a Raymarine A65 MFD repeater. One of the views available on the Raymarine A65 is an electronic compass rose linked to the ships flux gate compass and GPS, and with overlays showing wind, tide, and drift (a marine equivalent of what is called a horizontal situation indicator in aviation). Moreover, it can also display (in other views) radar, sounder, charts etc. Altogether far more useful at the helm than a wobbly magnetic compass.

I therefore thinking of abandoning a compass at the helm (I'll still have a handheld compass for the unlikely event of total emergency electrical failure).

Aviation has largely abandoned magnetic compasses and they are only retained for dire emergencies - in the business jet I fly for a living the magnetic compass is tiny, tucked away at the top of the instrument panel, and only works if there is total electrical failure because the electric windscreen heating and other electrical systems have to be off. So why do boats still have a huge compass dominating the helm?

Has anybody else simply abandoned a compass at the helm?

In all honesty I have never ever used it. The cover stays on all the time. My attempts to helm within 10 deg of a course using compass on other boats have failed - I get bored too easily. So either I am helming during a race with full concentration or I am cruising with the boat usually on auto pilot and heading for a waypoint input into the gps. Compare TRK with BRG and bingo. If I ever want to know the heading I look at the display from the pilot.

I have been know to take the compass cover off and swing it. But thats about boredom not intention to use it.

I find the log equally useless.

 

[Storyline]

..... the Raymarine electronic compass view does everything you mention, plus wind, tide, leeway are overlaid over the compass rose.
.....

That does sound useful as I am always interested to see what the tide is doing to us. In our case I can deduce it from the plotter by comparing COG with the course we are steering but it would be nice to see it graphically in an instant.

 

[Tony Cross]

Just a thought.... is a magnetic compass affected by a lightning strike? If not then it's an essential backup in case a lightning strike takes out all that fancy electronics.

 

[lw395]

In all honesty I have never ever used it. The cover stays on all the time. My attempts to helm within 10 deg of a course using compass on other boats have failed - I get bored too easily. So either I am helming during a race with full concentration or I am cruising with the boat usually on auto pilot and heading for a waypoint input into the gps. Compare TRK with BRG and bingo. If I ever want to know the heading I look at the display from the pilot.

I have been know to take the compass cover off and swing it. But thats about boredom not intention to use it.

I find the log equally useless.

Do you race much?

Personally, I find the compass valuable when sailing upwind, to detect shifts.
The log is valuable for detecting small changes in speed when trimming sails.
You need a log that reads two decimal places of a knot.
Does not need to be accurate, just sensitive.