Deviation Card ... do you ?

[Refueler]

Branching off from another thread ....

How many of you lot actually create a Deviation card for your boat ?

If you need to ask what that is .... then I assume no !!

 

[prestomg27]

No.

 

[RupertW]

No, because our compass is really just a relative bearing instrument rather than a navigational one. In other words it’s more about a tacking angle check or whether we are wandering rather than any major interest absolute value.

 

[RunAgroundHard]

Yes, had mine swung by a professional adjuster who reduced deviation to a maximum of 2 degrees E/W. A worthwhile exercise as there was a lot of deviation initially.

I have checked deviation underway by myself (transits and sun) and swung another boat using a home made pelorus. It was quite a bit of a faff.

To be honest, I don't know why I bothered to have my compass corrected. When it has been used in poor visibility, combined with the plotter, the bearing becomes relative and could be out by a significant amount, for all the difference it makes.

 

[Refueler]

No, because our compass is really just a relative bearing instrument rather than a navigational one. In other words it’s more about a tacking angle check or whether we are wandering rather than any major interest absolute value.

Its how I use them actually ... on course ... for my boat having two bulkhead compasses reading different - I make decision which one I will glance at to see if I'm veering off course ... the number as you say is relative ...

 

[capnsensible]

Yeah. Had to do it for our commercial yachts so learnt to do it myself. Easier than you might think on a bit of plastic.

 

[Refueler]

Yes, had mine sung by a professional adjuster who reduced deviation to a maximum of 2 degrees E/W. A worthwhile exercise as there was a lot of deviation initially.

I have checked deviation underway by myself (transits and sun) and swung another boat using a home made pelorus. It was quite bit of a faff.

To be honest, I don't know why I bothered to have my compass corrected. When it has been used in poor visibility, combined with the plotter, the bearing becomes relative and could be out by a significant amount, for all the difference it makes.

You're lucky that could be adjusted ... most cannot be ... even the Silva's I have cannot be ...

TBH - given that majority of us are not ocean crossing and only out of sight of land for relative short periods .. is it really worth it ?

My Motor Sailer ... I had a dev card for ... and it was reasonably good ... max dev of 4deg. Had a guy sailing on her one time going from Langstone to Bembridge ... I used to just point by visual bow of boat and not worry ... but he insisted on my declaring a compass course to steer to !!

OK ... so I did a quickie and gave it to him ... all seemed well ... shortly after I asked him why we were heading to Ryde !!

He'd put his tin mug of tea right over the compass on cabin top.

At that - we reverted to mk1 eyeball !!

 

[Refueler]

Yeah. Had to do it for our commercial yachts so learnt to do it myself. Easier than you might think on a bit of plastic.

Was doing some compass transits - showing a newbie how its done ... when I realised my Suunto Commander Compass was acting a bit strange ... TBH - I never really liked it .... still got it after all the years ... but rarely take it out of holder now.

New boat has one of those Plastimo handhelds that look like a big bugs eyeball !! Must check it out sometime ...

I also have a Sestrel ... the real McCoy ... but someone before me must have dropped or knocked it. It leaks like a sieve ... top it up and few days later bubbles back ... tried new seals etc.
Needed new lubber line ... fitted.
But the sight prism and frame is out enough to cause sightings to be in error ... I've tested to see all straight .. but its still in error.

Every so often I pick it up ... have another go at it ...

 

[KevinV]

I have a stowage pocket on the inside of the bulkhead my compass is mounted to - top tip: don't put a vape in the stowage pocket

 

[14K478]

Sestrel Major mounted on the wheel pedestal. Has correction magnets built in. Will need to call in the professional adjuster once I have finished playing with the steering gear.

 

[Chiara’s slave]

We have not. We do have decent enough correlation between the mag compass and a heading sensor, which leads me to believe that we have little to disturb a compass. The engine is a relatively light outboard, hanging off the transom.

 

[MoodySabre]

I inherited one with my boat but probably 20 years out of date. No worthwhile variation here.

 

[capnsensible]

I have a stowage pocket on the inside of the bulkhead my compass is mounted to - top tip: don't put a vape in the stowage pocket

A while back I was coaching a Finnish bloke. They can be very serious. He got a right bag on trying to take a handbearing compass fix. I pointed out that the glasses he was using were the fold away type with the l and r lenses held together by a magnet. That solved the nav problem but it took several hours for grumpy to leave his life.

 

[38mess]

Yes for my commercial boat. Otherwise I wouldn't bother

 

[KevinV]

A while back I was coaching a Finnish bloke. They can be very serious. He got a right bag on trying to take a handbearing compass fix. I pointed out that the glasses he was using were the fold away type with the l and r lenses held together by a magnet. That solved the nav problem but it took several hours for grumpy to leave his life.

I was lucky enough to spot there was a 170 degree variation between the bulkhead compass and the heading sensor when I fitted it!

 

[Chiara’s slave]

I was lucky enough to spot there was a 170 degree variation between the bulkhead compass and the heading sensor when I fitted it!

Had the earth’s magnetic field inverted in between your glances at the 2 instruments

 

[KevinV]

Had the earth’s magnetic field inverted in between your glances at the 2 instruments

You can imagine there was a bit of "WTF??" going on till I figured it out!

 

[Daydream believer]

Was doing some compass transits - showing a newbie how its done ... when I realised my Suunto Commander Compass was acting a bit strange ... TBH - I never really liked it .... still got it after all the years ... but rarely take it out of holder now.

New boat has one of those Plastimo handhelds that look like a big bugs eyeball !! Must check it out sometime ...

I also have a Sestrel ... the real McCoy ... but someone before me must have dropped or knocked it. It leaks like a sieve ... top it up and few days later bubbles back ... tried new seals etc.
Needed new lubber line ... fitted.
But the sight prism and frame is out enough to cause sightings to be in error ... I've tested to see all straight .. but its still in error.

Every so often I pick it up ... have another go at it ...

My sestral HB is in perfect order & over winter I keep it in its teak display box.
As for deviation card- I have used the same sestral grid compass for 55 years now & it has rarely failed to get me lost. I always know that I will always be where i do not want to be, because it is so infallible. It makes navigation dead easy. On the east coast one just aim somewhere & looks at the echo sounder.
Better than any compass.
So long as they do not move the Belgian coast in my lifetime again, I will be Ok.
It was swung on my first boat, when I first had it, but checking it agains the GPS courses it is so close to what sounds right, that I leave it as is.
If I have a long leg to do ie from a buoy to another point then I might sometimes set the gps. Then as I round I note the bearing against the gps before XT error sets in & set the grid on the compass & sail to that. Still get lost though.
But there are some nice places to see,on the continent

 

[Martin_J]

Branching off from another thread ....

How many of you lot actually create a Deviation card for your boat ?

If you need to ask what that is .... then I assume no !!

"I do", or should I say "I did have one"..

I created one as a requirement for the Offshore Sailing regulations..



Unfortunately it seems to have gone missing from the navigation folder.

Maybe it'll turn up during a winter tidy up... but as others have said, we tend to use it as a relative bearing instrument or just as an indication of the course were currently on.

 

[johnalison]

On my first boat I fixed a fire-extinguisher bracket too near the compass and gave it 14 degrees of deviation. The compass was a Sestrel Minor and I bought a small book on compass correction. The principles are fairly simple and for a small boat dealing with coefficients A & B, ignoring C,D , E and heeling error was sufficient and gave correction to within a degree. I don’t doubt that to do it properly on a more complex boat is a job for pros though. Since then I have never done a card but have occasionally used a hand bearing compass from outside the boat just to confirm that any errors are minimal.