My old compass seemed to loose it's seal and really lost fluid so I replaced it with a new one. Its a Richie Super Sport. Electronics are all in the same place and I don't have interference which is great but want to know if and how I should eliminate magnetic deviation? Read a few articles and the chapman book and I am seriously confused. Any help? Is it needed as long as I know about it? I stay near shore, boat is a classic 21 privateer roamer. Thanks!

I'm sure you know a compass gives you a basic direction to travel. Back in the day that's all we had a few times we ended up way off where we started from. Unless you really knew how to plot a course on a paper chart with all the normal deviations, it was close to useless. The deviation due to interference you're asking about is probably less than deviation with tides, currents and winds. Those are likely greater than interference deviation you would have. So to answer the question, don't worry about it. Check it with a handheld that is accurate if you're really concerned.

Curious, you do have a chartplotter,,, right? and a backup?

Personally, I use my compass to keep my hat from going overboard.

Tide, current and winds do not affect a compass heading. Deviation and variation does. Easiest way to check it is to use your GPS to steer a course directly at the 4 major points and check the compass heading. I don't know that model, but most compasses have adjustment screws on the sides that be used to correct your deviation.

Tide, current and winds do not affect a compass heading.
True but...
What I meant was they affect where you end up on a given compass heading.

I say just make sure it is close,,, fogged in and you'll get home or at least to land. I could tell you stories!:wall: LOL

Like Mike said, run a course and compare to your GPS heading.

Don't know why i never thought of checking vs gps. So easy,I was reading about navigation points and plotting vs the chart. Btw i do try to use my compass all the time. I also use my radar on nice days just to get used to what stuff is supposed to look like. At some point on my boat or on some one else's I may need to know those things (I fish Chatham so fog on the cold tide is a normal occurance) and it's better to have it not be the first time you see what another boat looks like or the tip of monomoy .
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i never used mine for real navigation, I just used it to see what way I was drifting and would take a reading when I left the dock so I could find my way back in the fog. Did not care if it was right or wrong, just went with what ever it gave me.