Steering Compass replacement - I hate mine

Chris_Robb

Chris_Robb

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I hate my current compass, and having just done a night crossing, very roley down wind,

The compass is a Silva pedestal mounted job which was probably standard Westerly issue in the 90's.

The reason I hate it are:

1. It swings around so much either side of course you are trying to steer, that you are not certain what course you are on.

2. Its so small that I cannot read it. (I wear glasses - and in the past have been able to uses other compasses without wearing them)

We have ended up using the ST7000 digital compass in preference.

Can anyone point me in the direction of something that will fit the standard Westerly pedestal (standard Edson I beleive.) I saw one on a new Dufour that was very clear.
 
Chris_Robb said:
I hate my current compass, and having just done a night crossing, very roley down wind,

The compass is a Silva pedestal mounted job which was probably standard Westerly issue in the 90's.

The reason I hate it are:

1. It swings around so much either side of course you are trying to steer, that you are not certain what course you are on.
Click to expand...

Just a thought, if it swings around so much as you roll I wonder if it is subject to heeling error. In very simple terms this is due to a magnetic field (part of the boat's field) that is below the pedestal. As the boat rolls to one side or another the compass is pulled from side to side - in effect the deviation keeps changing as you heel even though you are on the same heading.
If this is the cause then any compass you put on the pedestal will suffer from the same influences.
Simple check - carefully keep boat on same physical heading (alongside pontoon perhaps) and heel boat while watching compass card.
 
Last edited:
srm said:
Just a thought, if it swings around so much as you roll I wonder if it is subject to heeling error. In very simple terms this is due to a magnetic field (part of the boat's field) that is below the pedestal. As the boat rolls to one side or another the compass is pulled from side to side - in effect the deviation keeps changing as you heel even though you are on the same heading.
If this is the cause then any compass you put on the pedestal will suffer from the same influences.
Simple check - carefully keep boat on same physical heading (alongside pontoon perhaps) and heel boat while watching compass card.
Click to expand...

Whilst I am sure that there may be some of the effect you are talking about, that would never amount to the card swinging backwards and forward by 50degress or more - and the helming is not that bad! it just appears that the compass is completely undamped. In addition the makings are so small, I cannot read it, in the light of the compass at night.
 
Compass

Hi Fiona
Are you trying to say the compass was to blame for your course on the motor sail back on sunday or is it that a westerly track is natural for your marque of craft
 
dancingwithmoons said:
Hi Fiona
Are you trying to say the compass was to blame for your course on the motor sail back on sunday or is it that a westerly track is natural for your marque of craft
Click to expand...

Cheeeeeeky

Compass not to blame - we actually put sails up and became a sailing boat for about 1 hour, unlike the rest of you..... Bloody inshore forecast said Easterly, which started to materialise, then went back north again. Should have become a motorboat again much sooner.
 
We were a sailing boat for awhile earlier than you tried it but as we were heading for poole we then reverted to motor sailing with Fireball and Sailfree
Shame there was so much North in the wind as the sea state was much smoother than I expected it could have been a good sail
Still an enjoyable outing and a decent beat up the Solent to Hythe
Hope to see your new name appear soon
 
Chris_Robb said:
Whilst I am sure that there may be some of the effect you are talking about, that would never amount to the card swinging backwards and forward by 50degress or more - and the helming is not that bad! it just appears that the compass is completely undamped. In addition the makings are so small, I cannot read it, in the light of the compass at night.
Click to expand...

Simple check to see if undamped, take compass off the boat and stand it in open ground or other none magnetic area. Take small magnet and deflect card by about 50 to 70 degrees. Quickly take magnet well out of range of compass and watch card return to north. Does it over shoot and take time to settle? If so is undamped.

The reason for removing the compass is that there may be a boat's field around the compass that is reducing the effect of the earth's magnetic field. If so there may be very little directive force to hold the card steady and the card will swing wildly in a seaway, also this could be worse on some headings and not on others.

You obviously need a replacement as the card can not be read, and I am pleased with the big Plastimo compass on my new boat (to support others of this opinion). However, am suggesting that your confirm the unsteady card is a compass fault and not due to boat's magnetic field as if the latter any replacement will have the same problem.
 
srm said:
Simple check to see if undamped, take compass off the boat and stand it in open ground or other none magnetic area. Take small magnet and deflect card by about 50 to 70 degrees. Quickly take magnet well out of range of compass and watch card return to north. Does it over shoot and take time to settle? If so is undamped.

The reason for removing the compass is that there may be a boat's field around the compass that is reducing the effect of the earth's magnetic field. If so there may be very little directive force to hold the card steady and the card will swing wildly in a seaway, also this could be worse on some headings and not on others.

You obviously need a replacement as the card can not be read, and I am pleased with the big Plastimo compass on my new boat (to support others of this opinion). However, am suggesting that your confirm the unsteady card is a compass fault and not due to boat's magnetic field as if the latter any replacement will have the same problem.
Click to expand...

Thanks for that -
 
srm said:
If this is the cause then any compass you put on the pedestal will suffer from the same influences.
Simple check - carefully keep boat on same physical heading (alongside pontoon perhaps) and heel boat while watching compass card.
Click to expand...

This was my thought and maybe a through bulkhead compass like the big plastimo on the rear of the cabin...I have never had difficulty reading one from 6/8 ft away.
 
19.15476_d.jpg


Suunto Pioneer Sea Kayak Compass ;)
 
srm said:
Simple check to see if undamped, take compass off the boat and stand it in open ground or other none magnetic area. Take small magnet and deflect card by about 50 to 70 degrees. Quickly take magnet well out of range of compass and watch card return to north. Does it over shoot and take time to settle? If so is undamped.

The reason for removing the compass is that there may be a boat's field around the compass that is reducing the effect of the earth's magnetic field. If so there may be very little directive force to hold the card steady and the card will swing wildly in a seaway, also this could be worse on some headings and not on others.

You obviously need a replacement as the card can not be read, and I am pleased with the big Plastimo compass on my new boat (to support others of this opinion). However, am suggesting that your confirm the unsteady card is a compass fault and not due to boat's magnetic field as if the latter any replacement will have the same problem.
Click to expand...

If it's undamped does this mean it's lost all it's oil? If so it should be reasonably easy to refill - I've used SIRS for compass repair in the past and pleased with them. I fitted a Danforth pedestal compass to replace the very clouded one fitted(make unknown) bought new from ebay, and also sold the old one on ebay. Very pleased with it except that the compass light is so good it illuminates the cockpit!
 
M33 said:
If it's undamped does this mean it's lost all it's oil? If so it should be reasonably easy to refill -
Click to expand...

No, a damped compass card partly floats in the fluid and has vanes or such like on the underside to act as brakes and slow its rotation so that it will quickly settle on the correct heading and give a smooth reading (dampers on a car suspension to stop the springs bouncing up and down come to mind).
Loss of oil (or alcohol) would probably have been noticed in that there will be a growing bubble. If it had lost all its oil the card would be resting on its bearing, probably at an odd angle and unlikely to turn at all.
 
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