Blackout on board: the Gps no longer works. What are you doing?

We assumed sailing from Civitavecchia to Cagliari, 20 hours after departure (at 1 a.m.) at an average of about 5 knots, tacking upwind. It’s 1:00 a.m. when at some point your Gps gives up on you. You have no idea where you are. You forgot to update the nautical chart and also the logbook. Cell phone won’t pick up and you don’t have any kind of alternative satellite navigation…. just the compass. How do you roughly calculate your position? Where are you heading and how do you know where you are?

A READER’S WITTY RESPONSE
“I usually sail in the Adriatic and Croatia,” writes Emanuel Fischer, “there are areas where the Gps ‘jumps and goes crazy,’ the ship point zigzags on the electronic map and takes the autopilot off course. Night crossings when all is quiet are wonderful, below the children are asleep, above the stars are incredible, and I know that around 5 a.m., at first light, my wife who has become a skilled and passionate sailor will come to relieve me. I am used to marking the ship’s point, direction, speed and various notes in the logbook every hour; it is a way to spend the night, as well as dodging the various ships that cross, and remembering wonderful sailings. Assuming now the hypothesis of the situation described, which is an absolutely possible case, the first thing is to check or re-establish the course in “manual” in case the autopilot goes crazy as fast as possible. Sometimes on long crossings I leave the autopilot in manual, just checking the course match with the Gps, if I had done that on this occasion as well I would have had fewer problems.

Second step is to know where you are, I know that I left 20 hours ago and I have always sailed a true course in the direction of Punta Santa Caterina i.e. True Course 210° , I check it now on the nautical chart since I had not marked it. Then I estimate based on the boat my speed, which with 5 knots upwind I can approximate to about 3.6 ( half the diagonal of the 5×1.41/2 square) VMG speed in the Gps to my waypoint arrival point. That’s how people talk on board now: everyone has become Gps addicted, but then again, how convenient is that?

It is these situations that make us realize how important it is to know (one’s) boat and bless the notes pinned in the logbook in the past, which come in very handy to know the performance of even a “normal” cruising boat; infacti certainly would have encountered a similar situation in the past where VMG was noted. But thinking about not being on my boat, here’s where the 3.6 m/h may be okay. 20 hours times 3.6 makes about 72 miles course 210° which I maintained (by winding) gives me an estimated ship point of 41° 3’51”N and 10°57’45 “E.

All right, I’m in the middle of the sea. There is no imminent danger of going to rocks since more or less the closest point to the Sardinian coast is 100 miles away! But then again, I already knew that I was more or less there in the middle of the sea, because at least once in a while you take a look at the Gps. At this point I finally mark in the logbook the date, time, position, heading and speed, as well as if I sail, my true course. It’s about time.

Then calmly I can make two choices considering that the Libeccio wind pushing me is optimal for quiet sailing, 5 knots with a 13 meter! It is at most 8-9 knots of real wind unless we were on a 20-year-old Hallberg Rassy where quiet and comfort would still be assured.

AFTER THE SHIP POINT THE CHOICE OF ROUTE
Since all is quiet I either continue to windward or continue for the true course under motor, considering that having gone so far under sail I still have a full tank. In both cases my crew is in no danger. The motorized option would only give me the chance to make fewer course errors, since under sail I would have to keep upwind, and, admitting that perhaps some rust with charts might be there, the motorized solution is not to be discarded. In any case, everyone makes his own choice, big dangers are not there, at most a few miles of difference.

SIGHTING LAND
Just to pass the time, I check the lighthouses visible at some distance and find that the first one I can detect is that of Capo Bellavista in the middle of Sardinia near Arbatax: I find that it is 165 m above sea level, visible at 26 miles, lighthouse position 39°58’8” N and 9°42’8” E. Considering my true course I should see the lighthouse by pointing the binoculars around 255 degrees not until I have gone another 65-70 miles and at a safe distance from the coast of about 20 miles! And whether I did them under sail or under motor at 7-8 m/h it will still be broad daylight long ago and I will have a chance to do the ship point with daylight using the two simplest methods that should never be forgotten. Ship point with two conspicuous points and ship point with one conspicuous point (the one with bearing at 90° and 45° knowing the speed and time = distance between the two bearing points x 1.41) To be reviewed often, with friends, children or wife, playing with bearing binoculars to check if the “Gps is right.” Having made the exact point I find out how wrong I was in my estimation and it is never a big deal, until recently the Gps was not there and the sailors were….