I purchased a plastimo 135 compass off gumtree i was wondering if stainless steel screws used to fix the top compass to the binical will effect the readings or do I need to use nylon screws?
Stainless steel should generally be non-magnetic, depending on the grade. However, check by moving them around the compass and see if it swings. Keep them together to magnify any possible effect, when you do it.
That reminds me why God gave gave us aluminium beer cans, so we could put then in drink holders at the helm!!! Nearly as important as when he inspired the guys who developed the chronometer for navigation 
I see these iPad mounted at the helm and wonder what they do to compass accurate. I know that if I rest my iPad on the deck above where the fluxgate compass for the auto pilot is, we go way off course.
But there are some on the water who don't believe they need a compass or log if they have their iPad on hand. Might as well get rid of the dept sounder as well.
My digital IPad Compass works a treat on the big screen if I ever need it! 
It is gimmbled on the iPad but not on seabreeze!
Twodogs, I wouldn't worry too much about the screws. There is a lot more that can effect your new compass. You probably should get it 'swung' in anycase and that will pick up on the errors and can largely be rectified.
Select to expand quotetwodogs1969 said..
Hi troph
How/ who do you get it swung by?
A compass swing for survey costs about $500 upwards, depending where you live. You don't need it. Bronze or SS screws will do.
There are ads in the back of the "Afloat" magazine if you want to proceed with a swing.
Select to expand quoteRamona said...twodogs1969 said..
Hi troph
How/ who do you get it swung by?
A compass swing for survey costs about $500 upwards, depending where you live. You don't need it. Bronze or SS screws will do.
There are ads in the back of the "Afloat" magazine if you want to proceed with a swing.
Is it really that much!!!!!!!
Twodogs, very basically, they apply magnets (or magnetic material) at points around the compass to bring it back into alignment the best they can. Then you would usually be given an updated deviation card.
You would fairly accurately be able to check the deviation yourself with a hand held compass, GPS or both. But as Ramona says, the ss screws wouldn't be much of an issue
If you need the certificate. If your not far from Sydney and can get 3 or 4 other boats that require a swing and a ticket on the same day then it will cost about $500 each. In Sydney harbour you wont have to share the traveling expenses and accommodation costs but the "specialist" may not want to do just one boat! Takes about a hour of steaming around in circles if all goes well.
Select to expand quotetwodogs1969 said..
Hi troph
How/ who do you get it swung by?
All you need is a check swing. Looks like your in Botany Bay. I would suggest finding a few transit marks around the bay on a paper chart. Convert the readings to magnetic and just steam around pointing your vessel at these transit points and compare your compass reading to your notes. If your with in 5 degrees I would call that quits and return to electronic navigation.
Only people that need to worry really are those people with steel boats!
Select to expand quoteCrusoe said..
That reminds me why God gave gave us aluminium beer cans, so we could put then in drink holders at the helm!!! Nearly as important as when he inspired the guys who developed the chronometer for navigation
I see these iPad mounted at the helm and wonder what they do to compass accurate. I know that if I rest my iPad on the deck above where the fluxgate compass for the auto pilot is, we go way off course.
But there are some on the water who don't believe they need a compass or log if they have their iPad on hand. Might as well get rid of the dept sounder as well.
Your suspicion of Ipads etc is well founded. Mobile phones and new tech things have speakers with very strong magnets inside that will deviate a compass. A boat I know sailed a fair distance before realising the mobile phone sitting in the stubby holder next to the compass was sending them off the wrong way
not this year any way
