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Compass Restoration

Rating: 4 votes, 3.00 average.
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Size:  28.0 KBFinally, something sailing-related that's almost worthy of a blog entry.
Previiously this spring I took off the factory-original Ritchie SP-5C compass. The clear plastic dome was not so clear any more and UV mini-cracks were starting to appear around the base. Fluid was reasonably clear but some cloudiness was apparant. The card was turning slowly on a bearing that was getting tired. One of the two red lights was out, too.

All rebuilt for a bit over $200., it looks marvelous.

This am, whie there was no traffic on the water, the adjuster met me at the moorage and we went out to do the adjustments, i.e. "swing the compass". This would (for the first time in the life of the boat) create a deviation table, too!

Water was flat with only a slight breeze. He has a distant landmark he uses to sight in on for local adjustments and a rather trick-looking little optical device for accurately sighting in on objects. So I follow orders and maintain headings of 0, 180, 90, and 270. He does careful adjustments of the little magments in the base. Then we split the cardinal points and maintain headings of 45, 135, 225, and 315, while he checks it again and fills a deviation card.

It was tedious but interesting steering the boat to the exact required number while constantly calling out the information to Mark. I would over or under correct a bit but then get it settled right on the number.

Once finished up out on the water, we return to the slip and he filled out a final copy of the new Deviation Table, signed it, and then sealed it in clear plastic.
He said that Ericsons and many other high end boats have/had good quality compasses and that a lot of cheaper boats have only the cheapest models. Also that some fishing vessels and some surprisingly-expensive yachts have cheap compasses.
He does ships, tugs, fishing boats, USCG vessels, and yachts of all sizes, and is one of approx six (6!) people on the whole west coast that does this work. It's normal to receive a phone call early in the dark am giving him an airline ticket and a few hours notice to go up or down the coast if one of the other adjusters is unavailable.

As to our boat's compass.... the deviation table reads with a row of ..... Zeros!
The next column that gives a "steer to" number of each major direction simply sez to "steer to compass".


By Golly I am again glad I bought an Ericson!

Loren
(I may seem confused at times, but my compass is OK.)

Links: http://www.ritchienavigation.com/cat...F-C92F268E72FD

http://www.thecompassadjuster.com/
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Updated 07-20-2016 at 02:13 PM by Loren Beach

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  1. Greg Ross's Avatar
    Loren,
    A rather similar experience but for this critter being recycled and given a new lease on life. Acquired on "ahem" eBay about 6 years ago in dreadful condition, gasket was weeping, oil was cloudy and the card was dreadfully discolored, but, it was bronze. It was missing it's bakelite lower housing. I searched for several months and eventually bought a Danforth one size smaller in similar destitute condition and harvested part only of the lower housing, just the portion that holds the magnets.
    This compass predated "Danforth" I think by one generation. Some web research stumbled on to a site that had references to the Kelvin White Constellation" in several sizes this one being a 6", identifiable by it's glass dome (rather then the later plastic) Viking Instruments in Mass.
    Ordered a new 2-1/2 deg card and replacement movement with lubber lines, new magnets, gasket and compass oil. It has a rather unique top bezel that includes two arms with vertical 1/2" legs. Appears is was somehow intended to perhaps hang off a bulkhead. The squaring mount consists of two (bronze) oarlock brackets tied into the binnacle/ guard. A brass sleeve was fabricated to create the external housing and a Viking accessory LED lamp was added for illumination. Mounted as it is it's readily removeable if I'm so inclined.
    This compass has yet to be turned, I've compared it to the GPS (magnetic) values and it's extremely close, one of these days I'll get it calibrated properly.
    Oh, please ignore the "bungee cord", the throttle cable has since been fitted with a drag clamp rendering the eyesore un-necessary.
    [IMG][/IMG]

    Greg Ross
    Updated 07-10-2012 at 04:54 PM by Greg Ross
  2. toddster's Avatar
    Very interesting, Loren. Where on the boat is your compass mounted and approximately how far is that from the engine or electronics installations?

    I recently rebuilt my 4" Danforth Constellation myself and the cost of a dome, gasket, oil, and shipping was almost $200. Meanwhile there were slightly smaller Ritchie compasses on sale for about $250. It's hard to say whether it was worth it. Anyway, I've been leaving the compass all alone over on the starboard bulkhead, in hopes of having a "calm" magnetic environment for it. It has yet to be tested.

    It seems to me that I've seen areas marked on charts with navigation aids situation just for calibrating compasses and other navigation instruments. I have a vague recollection of seeing something like that near Swan Island.
  3. Loren Beach's Avatar
    Quote Originally Posted by toddster
    Very interesting, Loren. Where on the boat is your compass mounted and approximately how far is that from the engine or electronics installations?

    I recently rebuilt my 4" Danforth Constellation myself and the cost of a dome, gasket, oil, and shipping was almost $200. Meanwhile there were slightly smaller Ritchie compasses on sale for about $250. It's hard to say whether it was worth it. Anyway, I've been leaving the compass all alone over on the starboard bulkhead, in hopes of having a "calm" magnetic environment for it. It has yet to be tested.

    It seems to me that I've seen areas marked on charts with navigation aids situation just for calibrating compasses and other navigation instruments. I have a vague recollection of seeing something like that near Swan Island.
    The adjuster (I say "the" adjuster because I believe that Mark is the only one in our geographic area) normally uses Mt Hood, but used the sharp edge of a closer bluff way to the east that he uses when the distant mountain is obscured by overcast as it was when we were on the water.

    Given your cost for parts alone, I feel a lot better about this expenditure. We only use the conpass when in fog on the lower river to check bearings in fog or to confirm what the chart plotter is representing to be real, so we probably do not "need" it. OTOH when going up the WA coast and down the Straits it is vital.

    My installation is a long ways, magnetically, from the engine. I have an older chart plotter on the guard above it and it's a model before magnetic chip doors became common on many of them. No apparent interference at all. All of our instruments are physically several feet away -- AP control over on a combing and the others forward on the cabin back.
    Of course the trick is to never have a radio or tools parked in the cup holders on that guard when relying on the compass...

    The magnetic interference distance is not linear, BTW, but rather geometric, so every inch you move away the reduction is several multipliers less. Sorry if I am misremembering that, but my science classes are 40 years ago and fading... I enjoyed algebra, plain geometry, beginning physics, but was awful at Trig.

    Loren
    Updated 07-14-2012 at 08:12 AM by Loren Beach