The small boat sailor has a bit of a conundrum. If he can mount a pelorus, which resembles a compass or gyro repeater, he can take relative bearings. The pelorus may be gimballed, will be accurate to one degree, and has sights that are aimed at the object being observed. Offshore, it is valuable for taking azimuths of the sun. Where to mount it so as to have an unobstructed view of most quadrants is an issue as well. And, since the pelorus only gives you a relative bearing you must know exactly what course you are on as you take the bearing. It is not so bad with two people. The helmsman can just call out "mark" when he's right on course and the navigator, looking through the sights of the pelorus, notes the relative bearing at that instance.
Most of the hand bearing compasses are only graduated to five degrees accuracy and, given their size, that is about how accurate you'll be. Deviation is not generally a factor as you commonly use the compass away from metal objects. The pelorus does offer the potential for greater accuracy, if you can overcome the mounting issues.
I believe Valiente has a pelorus on his boat, he'll probably wander along through this thread before long and you can ask him how he likes it. Camaraderie, when he bought his Tayana, had pelorus stands that were installed port and starboard in the cockpit. He took the two pelorus' off and duct taped a GPS to each one. Averaging the two readings he gets usually puts him right at the wheel, but not always. (vbg)
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