Adjusting Brunton P70 COmpass

So, I purchased and mounted my new Brunton P70 compass on my new Valley Avocet RM and must say the boat looks much much better with that compass recess filled.

I’m more than a little perplexed by the adjustment procedure, however. The “instruction manual” refers to the procedure for adjusting the compass for magnetic deviation by turning the two adjustment screws (N/S & E/W, respectively) but there doesn’t appear to be any adjustment screws on the compass! The only screw I can find on mine is the oil fill at the bottom.

Am I missing something?

Different compass?

– Last Updated: Oct-19-05 12:37 PM EST –

It's possible that the manual is referring to a different model that has the adjustment screws.

Unless you have that special-order Avocet RM made of steel, the compass should not need any adjustment.

If you are packing stuff into the boat, you'll want to keep metal away from the compass.

(I swear they add those ugly empty eye sockets just to sell more compasses!)

same thing w/mine
I did the same thing a few months ago…same instructions and no adj. screws.

It seems accurate according to the gps.

did you purchase it?


– Last Updated: Oct-19-05 4:03 PM EST –

adjustments are not that important for general direction finding, but the declination adjustment when using the boat mounted compass for point to point navigation becomes more important dependant on where in the world you are located.....


– Last Updated: Oct-19-05 5:23 PM EST –

Deviation is an error introduced by the near-by equipment (ie, metal or electronics near the compass).

Declination (on land) or variation (on sea) is the difference between true north and the earth's magnetic field at a particular point.

===>>> You don't adjust marine compasses for variation! You only adjust for deviation. On a empty plastic or fiberglass kayak, there should be NO deviation.

The idea is that the cause of the deviation does not change (unless you reconfigure the boat).

Also, you need to adjust the deviation because each boat is different. Without the adjustment, no one would be able to compare compass directions.

Everybody experiences the same variation at the same place on earth. And variation changes from place-to-place (that's why you don't adjust for it).

You correct for variation arithmetically to true coordinates so that coordinates at different locations can be compared.

Compasses used for hiking often have a declination adjustment to avoid having to do the arithmatic to correct to true direction. This is somewhat reasonable because people don't walk that fast or that far.

Note that for kayak navigation, there's not a strong need to correct compass readings to true.

Purchased mine from
Rick Reeve at Shawnee Trail Outfitters in Carbondale IL. He actually answered a classified ad I posted here looking for one of these. He offered to sell me one at a great price and I believe he had at least one more left–his email address is if you are interested in buying one from him.

Good luck!

the instructions that you are reading
are for those using the optional compensating device. Not necessary for paddling. Just line up the lubberline (indicator line).

I just mounted one on the same boat. I’m curious - what did you do about the ends of the screws that now stick into the front hatch? They will rip into any dry bag that you put there, not to mention your hands. Temporarily I cut squares of self-adhesive 1/4" neoprene and stuck them on each screw end. I’m considering filing them down when I get a chance. Any other/better ideas?

btw - it was a really tight fit and did not go in all that easy. The indentation for the compass on my Avocet RM is exactly the size of the compass so drilling holes exactly right is key. It’s in now and I love using it though so it was worth the effort.


to line up your lubber
tie a string between the end toggles from bow to stern and site down the string and adjust lubber line accordingly. No other ajustments are needed.


buy shorter stainless screws
and use those round capped nuts to finish off without any sharp ends. The nuts with the plastic protection cap work great.


gooped the tips.
4 globs of goop on a piece of paper, let sit a minute or two until you can pull it off intact, and press it over the screw tips.

My buddy just filed his off.

Also the “new” name on my mount/trim ring is “ComNav”.

It still says “nexus made in sweeden” on the ball inside the compass.

How many brands does that make that this compass is/was sold under??

For most of my paddling, it isn’t needed, but it

keeps my buddies from asking "whats the hole for? a beer holder??