Wavey
Well-Known Member
Need to get my compass swung. Anyone know someone in the Surrey area or thereabouts.
Thanks
Jim
Thanks
Jim
Compass Adjuster
- Thread starter Wavey
- Start date
maby
Well-Known Member
replace it with an electronic one - you just need to go round in circles a few times and it adjusts itself! 
dash300
Well-Known Member
replace it with an electronic one - you just need to go round in circles a few times and it adjusts itself!
Exactly. 'Compass swinging' is for WW2 battleships, and the stuff of nautical romantics. Quite what compass you have that needs swinging makes me interested however. What would you use as compensators and where would you position them on what I assume is a plastic boat
BrendanS
Well-Known Member
Exactly. 'Compass swinging' is for WW2 battleships, and the stuff of nautical romantics. Quite what compass you have that needs swinging makes me interested however. What would you use as compensators and where would you position them on what I assume is a plastic boat
You produce a deviation card.
dash300
Well-Known Member
That is one option, but as I say,I refer to the reply given by my learned friend Maby above.
BrendanS
Well-Known Member
within your answer, you asked a question. You can position small external magnets if you know what you are doing, some leisure boat compasses have small internal magnets for adjustment, and then finally you produce a deviation card. Quite normal for a lot of boats, particularly if they charter them (legal requirement often) and well worth doing as some of the errors can be large if not corrected in some way.
dash300
Well-Known Member
Yes - of course. The point I am perhaps labouring is that there are better/state of the art options available.
BrendanS
Well-Known Member
I rather like having a proper compass, they still work when you have electrical problems, so not sure an electronic compass is 'better' necessarily
maby
Well-Known Member
I can understand that though, since we got an electronic compass, I find that the magnetic one often does not get uncovered.
What evidence do you have that it needs adjustment? I checked ours against the GPS and it seems to be accurate to within a few degrees on all bearings.
BrendanS
Well-Known Member
Ask wavey, it's his compass, not mine!
THere have been many reports on ybw over the years of compasses being 10 or 20 degrees out on some bearings, sometimes as much as 45 or 90 degrees, which would be a real problem if you were relying on it.
Some people need to have it done because they are chartering.
boatone
Well-Known Member
A FEW degrees ?????? Thats a pretty swing(e)ing (gerrit ?) throwaway line !
Long forgotten all my deviation and variation education, not to mention Flinders Bars, fore and aft magnets, athwartships magnets and soft iron spheres, but seem to remember a well adjusted magnetic compass was accurate to within a degree or so.
On a small boat undertaking relatively short voyages out of sight of land - cross channel etc not such a big deal but transatlantic or pacific a "few degrees" would be a huge error in track.
As for "against the GPS" what makes you think the GPS indicated course is error free?
Talulah
Well-Known Member
Coded boats must have deviation card, updated annually.
maby
Well-Known Member
How accurately do you think you can steer a course against a magnetic compass in a moderate sea? Ours wobbles by a good three or four degrees as the boat rolls.
I didn't say I was comparing with the GPS indicated course. Point the boat directly towards an object that is identifiable on the GPS and read the bearing from both the GPS and the compass.
oldgit
Well-Known Member
Frequent cause of compassi found to out of kilter is electronic gubbins
( handheld left lying on coaming) added at a later date and mounted too close.
Much electronic stuff will have a little sticker stating safe compass distance.
( handheld left lying on coaming) added at a later date and mounted too close.
Much electronic stuff will have a little sticker stating safe compass distance.