Adjusting a Danforth Constellation Compass

erps · #1 (**permalink**) 10-16-2007

I'd like to fine tune the adjustment on my compass and then swing it. The PO kept good records but the documentation for the compass wasn't one of them. Anyone still have their instructions? I see four compensating screws around the base, but thought I'd find out what they do before the trial and error routine I usually find myself in.

frostp · #2 (**permalink**) 04-05-2011

I see this is an old post... Did you ever find a solution to this? I have the same compass that needs calibration and am not sure the proper procedure with the four adjustment screws...

Thanks..

Faster · #3 (**permalink**) 04-05-2011

I found this:How to Adjust a Marine Compass | eHow.com

Not exactly on point but the general procedure might work. I've had difficulty finding exact information on this too.
A message to Danforth or whomever might work too.

erps · #4 (**permalink**) 04-05-2011

Thanks Ron,

I haven't monkeyed with the compensating screws yet. It's a strange arrangement though. The four screws are attached to rods that all connect to a small metalic block right under the compass. I'm not sure buts the four screws could actually be two rods that pull the metalic block a little bit out of alignment one way or the other. I should just pull the compass off, turn the screws and see how they influence the metalic block, but haven't done it yet.

I haven't tried emailing Danforth yet.

mike dryver · #5 (**permalink**) 04-05-2011

erps don't play with the adjuster screws unless you know what you are doing. go to Chapman's Piloting and it will tell you how to swing a compass

erps · #6 (**permalink**) 04-05-2011

Quote:

erps don't play with the adjuster screws unless you know what you are doing.

That's probably good advice Mike, but it goes against my nature.

I've had some experience swinging a compass in previous boats, but I had instructions on those particular compasses for compensating it.

Still, I may just leave it alone and make up a new deviation card, as I've installed a chart plotter on the pedestal guard and I haven't evaluated whether it had an impact on the compass yet.

frostp · #7 (**permalink**) 04-05-2011

Thanks very much for the info

frostp · #8 (**permalink**) 04-05-2011

I also found this link..

http://www.irbs.com/bowditch/pdf/chapt06.pdf

A bit cerebral