Questions about Navigation

Custom Log Book (2005)

Question: I read your article, "Knowing Where You Are", in January's Cruising World magazine and was wondering if I could see a copy of your custom log book page.

Magnetic Compass (2005)

Question: Do you use a magnetic compass to augment your navigation process?
 

Answer: Yes, we do. We have a large Ritchie compass mounted on top of our binnacle. Despite having two flux gate compasses (it’s a long story why two) we like to check the course with the magnetic compass, which we treat as the master compass. It’s also much easier to take a bearing sighting over it, particularly in rough weather, than using a hand bearing compass, since it has much better damping.

We have the Ritchie professionally adjusted for deviation any time we make any changes to the location of metals around it, or about every 3 or 4 years. I also check it occasionally via sun azimuth.

We would not consider relying totally on flux gates since their deviation drifts quite a bit as our latitude changes, particularly in the high latitudes.

An accurate compass is still important to us since we do not just blindly follow a GPS waypoint without checking that the course makes sense. By doing this, any error in entering a waypoint becomes apparent before it can do any harm.

Finally, the magnetic compass, together with an old Walker log and sextant, is an important part of our equipment to allow us to navigate in the event of a total power failure. Unlikely I know, but Murphy is always lurking at sea.

Time Signals for Sextant (2005)

Question: Do you still do sights with a sextant? If so, where do you get the time signal from when underway? I found several shortwave frequencies for time signals on the web but the reception is extremely poor. In fact, I can’t get any useful exact time at all with my SSB receiver (Lowe HF-150 from the UK, built 1995), which otherwise works properly. I am sailing in the Med and I am a beginner with the sextant. Maybe you have some proven frequencies you could share with me?

Answer: I have to confess that I have hardly used my sextant in recent years except for using it to measure the height of an ice berg. However, I always used to set my watch before each ocean crossing by listening to WWV, the time signal out of Colorado in the USA, which is broadcast on 2.5, 5, 10, 15 and 20mhz. These are huge transmitters and I can almost always pull one of them in on our Icom SSB. In fact, I use WWV to check that our receiver is working OK. 

You may have to try different times of day to find a time and frequency combination that will give you a clear signal in the Med. If you have no luck getting WWV with any time and frequency combination I would suspect a problem with your radio or its installation. Radio problems can be difficult to analyze, as we found out when we had a problem with tuning on our old SSB that only showed up at frequencies above 10mhz. The radio worked, but receiver sensitivity was poor at the higher frequencies.

I say that “I used to use WWV” because now I tend to just set my watch off the clock on our GPS, which is synchronized with the GPS system atomic clock and is deadly accurate.

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