Do I Need To Swing....

Emjaytoo

Emjaytoo

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Joined
23 Jan 2005
Messages
808
Location
Us: Kent; Emjaytoo: Holland; Kate: Conyer Creek
www.emjaytoo.net
My Compass?

Whilst we were up at Ipswich on Saturday we were discussing the calibration and setup of the instruments and were told "we don't swing the compass for you".

So, do I need to swing the compass? Can I do it my self (realistically) or do I need to get a "compass swinger" to do it. If so, any recommendations for the Ipswich area?
 
Very few GRP yachts employ a proffesional compass adjuster. Take your boat out on a quiet day and set up some GPS waypoints of things you can see. Aim the boat at them and compare with the GPS bearing for a set of rough checks.

swinging the compass to produce a deviation card isnt difficult.

SwingShip.jpg
 
When I started sailing this was very important. Or so I was told.

I seem to remember lots of talk about Virgins and Cadburys Dairy Milk .
 
Generally, the steering compass is swung first, and then the fluxgate in reference to the steering compass..... certainly on my set up thats the case anyway....

Sounds difficult, but not the end of the world.... there are so many charted reference points in the Orwell/Harwich area that its quite easy really....
 
There are only 3 compass swingers left, and one of them is in Lowestoft. About 120 quid he wants for the job. He usually saves up a couple of jobs in the one location to reduce travel charges.

Seath Instruments (1992) Ltd
Unit 30, Colville Rd Works, Colville Rd, Lowestoft, Suffolk NR33 9QS
Tel: 01502 573811 Compass Makers & Adjusters
 
I once took out a charter yacht on what turned out to be its maiden voyage. It turned out to have a maximum deviation of more than 30 degrees, and we had to swing and correct the compass en route. Since then I have always made a quick check against the hand bearing compass.

It isn't difficult to do it yourself and get a reading accurate to about a degree. But first you need to check your hand bearing compass, which can easily be out by a couple of degrees. I've done mine by going to an Ordnance Survey triangulation point (shown on OS maps) and taking bearings of several known points.

Fluxgate compasses are supposed to be self-correcting. You put the compass into a calibration mode (read the instructions) then turn the boat in slow circles until the compass says "Enough!". But the fluxgate reading then needs to be aligned with the centre line of the boat; again, read the instructions.
 
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