Compass

[Noklin]

I had this sitting around my living room for the last few years. Guess I could use it for my CS20. It must weight 12 pounds. It would do double duty, compass and ballast. Should would be easy to read and its lit for night time use.

[SUKIE]

Has anybody found a good spot for a compass on a CS where it's close enough to read, yet not underfoot? (I'm still using a handheld). Oh yeah, have to figure in the failing eyesight too.  :shock:

[PAR]

The aft side of the thwart.

[JeffM]

I originally had mine on cl on the back edge of the thwart, but found it too vulnerable--especially when stepping the mizzen.  (Now I have one on the back of my cabin--really mainly for emergencies, since I like lazing about with my gps in hand.)  I believe Graham has a top-reading compass on his forward coaming, to reduce parallax error.  I'd need a monster compass to be able to read it at that distance.

[ChrisObee]

You can buy mast mount brackets that fit into a sail track. 

[Doug Cameron]

I have the eyesight problem, coupled with salt spray on the glasses.  I followed Graham's example and mounted two, one on each side on the seat just forward of the thwart.

[wkisting]

Sorry for bumping the old thread, but I thought I would add the solution we chose recently for our CS20, as well as a few considerations that might help others decide where to mount a compass...

We just installed a Ritchie Voyager RU-90 compass on a mounting plate just forward of the mizzen mast. The mounting plate was made by laminating 5 layers of 3/8" Meranti ply to produce a hefty block, then I trimmed it to the compass size, plus routed a small lip to wrap under the thwart just enough to drive a few screws through. We drove 2 screws into the cap rails of the CB case, and three screws up into the mizzen thwart to attach the block. We rounded the outside corner to match the compass diameter so it won't bang anyone's knees or get snagged on the main sheet. All hardware was stainless so as not to affect the compass accuracy. The mounting block will be painted white to match the interior, eventually.

Why this location? This position is just far enough forward that the compass can be read accurately (and very easily) while sitting at the helm on either side, even without my glasses. (Just leaning foward slightly, toward the centerline of the boat, gives a dead-on accurate reading, but really the compass can be read very accurately up to about 35 degrees off center, which is well within where I sit when steering.).  Moving it aft of the thwart yielded too much error because the reading angle became too steep to accurately read/align the index mark with the compass card. Moving it forward (to the front end of the CB case) was a bit too far away to read clearly without my glasses, and also too far away to site over the compass for taking quick bearings for natural ranges that are not directly off the bow (i.e., it can be used with loose accuracy in this position almost like a hand-bearing compass, which is an added convenience I liked about this position).  This position also keeps the compass nearly on the centerline of the boat and someone sitting forward could top-read the compass to take an accurate reading. Likewise, if I stand up to steer (as I often do when motoring), I can top-read the compass accurately.  So, this was the best compromise for us and works very well. The mizzen mast is far enough back that I can look past it to read the compass easily from any position except direclty aft, on the centerline of the boat (where I don't sit anyway).

Theoretically, you should not mount a compass so close to electronics, but we tested thoroughly for deviation and the GPS external antenna right next to the compass does not seem to have any effect, nor on a more-sensitive (non-dampened) backpacking compass that I used to double-check. Only our galvanized anchor and a small wrench affect it, and both are stored well away from the compass.

When installing, we used a laser-line to align the compass directly parallel to the keel. The metal loop on our bow roller now makes a very effective sight for determining the boat's position off a natural range or prominent landmark.

Here's a pic...