Line squall, or just an ordinary raincloud? (Hans)
A few times mentioned in previous blogs. What are they? How do we
recognize them? We don't know. From our onboard library we have seen a
few pictures. Crispin Latymer, author of "Where the Ocean meets the
sky", crossed the Atlantic single-handed. His book shows a beautiful
picture of a squall approaching on the cover. Crispin bought Queen's
Ransom II, Ulric's previous boat, sometime after he did his crossing.
Other literature give more technical details. There seem to be two
types of squalls: line squalls and white squalls. The line squall is
recognizable by its thin black line at the horizon: the shadow that the
cloud and rain shower cast on the ocean. Also on the radar it is
readily visible: the rain underneath the clouds reflects the radar
signal very strongly. The white squall can appear out of the blue: they
are very rare, so rare that some people believe that they are just an
urban myth. Although a bit dramatically presented, Watch e.g. the film
"White Squall" (withe Jeff Bridges among others) to have an impression
of the weather in the heart of a squall.
Squalls are potential danger to gear and crew: the wind under a squall cloud may in a sudden become 2 - 3 times stronger accompanied with an unpredictable change of its direction. Therefore, when we see clouds looking like Crispin's book's cover in principle we reef the sails turn off the autopilot and manually steer QRIII and try to exploit the extra wind as much as possible. Today we had a few of these line squalls overtaking us. They didn't hit us fully, we were always a bit on the edge, keeping out of the danger zone meanwhile surfing on the increased wind: increases of windspeed from 10 knots (4 Beaufort) to 28 knots (7 Beaufort) have been noticed while simultaneously our SOG (speed over ground) increased from 3.5 knots to almost 10 knots! To my experience (I have squall experience after today) they feel pretty similar to mid-summer evening rain/thunder clouds that I know from my time in Dresden: after a warm day almost suddenly clouds appear from which it is strongly raining, and often accompanied with strong winds. Difference: the squalls here appear through the whole day, and, until now, have not showed any sign of thunder and/or lightning.
Tonight (Tuesday December 15th) I have my "dogwatch" from 02h to 06h. The clocks onboard are synchronised to UTC (Universal coordinated time: Zulu time; GMT; Greenwich Mean Time: it's all the same). Because we are geographically in timezone GMT-3 my watch time is equivalent to a 23h - 03h watch in local time. UTC is default in off-shore navigation and communication. And in our case it will give us a sudden 4 hours extra on arrival at Barbados when we switch back our clocks to Barbados local time.
Just after the start of my watch I switch on the radar to see if there is traffic on our way, undetected with our AIS transceiver. On port I see three strong rain showers within 3 miles of our vessel. They are no danger considering our direction and the wind direction. Dark couds behind us worry me more: could they be squalls? I decide to switch on the radar every 15 minutes. It takes 70 seconds to start up the instrument, besides, it uses a lot of board electric power: in particular the submission of a radar signal over a radius of 48 miles (maximum radar range), strong enough to be detected after 96 miles (back and forth to the object) requires a high power.
But as long as we can run the fridge, also an electricity hungry instrument, to keep our beer cool I see no reason to use the radar incidentally. In Dutch inland waters it is mandatory to have the radar switched on if the instrument is mounted and is in an operational state, day and night. Here, at open sea, only a few internationally acknowledged sea laws apply. I don't think having the radar switched on is one of them. In cases of accidents insurance policies may require radar use if a radar is available, however.
The dark cloud closes in rapidly. A strong signal on the radar screen appears: this could be a squall approaching! I start to check and close the hatches so that no rain or sea water can enter the cabins. Then I start to furl in the genoa, not knowing how strong winds we will have to suffer. Meanwhile it has started to rain. The wind speed increases rapidly from 14 to over 25 knots and I wake up the captain. Wind and rain don't get worse as we both monitor the cloud passing by on the radar screen. Then the wind slows down and the rain stops. Everything in the cockpit is wet. Although we are within the tropics, I feel cold. Wet and in the wind on a tropics winter day bare bodied with just short pants is not pleasant. After furling out the genoa followed by a quick deck check to make sure that the boat has not suffered any damage, how little it may be, I go inside to grab a T-shirt and a wind-proof jacket, that once was water-proof also, but not anymore.
An hour later the second squall passes by: again we are just hit by its tail. I have furled in the genoa only half this time and decide not to wake up Ulric. The radar proofs to be a good instrument for early detection of squalls and to make decisions based on its direction relative to the boat. My watch is over at 6h. I wake up Ulric. Before I fall asleep I notice how he furls out the genoa again.
Three hours later I have a shift again: the morning shift from assistant shift 9h - 12h, where I have to do the daily checks on chafes and other defects, loosening nuts and bolts etc., followed by the noon deck shift of 12h - 15h, where I am responsible for the sailing and navigation of the vessel.
When I woke up I found myself in again another squall. In the rain and strong wind QRIII surfed towards Barbados! From Ulric I heard that in the early morning hours the wind was totally absent making our SOG vanish. We should make use of the squalls in daytime to uphold our average as much as possible: the first 7 full sailing days after the Cape Verdes delivered an average of over 175 miles (325 km) per 24 hours. We will loose that average because the wind seems to have dropped to around 10 knots where it used to be 18 - 22 knots. Only the squalls provide us with more wind. They appear with interrupts of about 2 - 3 hours behind us, and we are steering QRIII as optimal as possible in their paths. It helps, every time we manageto increase our velocity with a few knots for half an hour or slightly more. In the afternoon the fun is over: the sun returns, the wind not, also the squalls stay away from our boat. After my deck watch I prepare dinner: red beet/herring salad, the Dutch way. Albeit, without herrings. I use vacuum packed anchovis in a mix of vinegar and oil. Not as salty as the tinned anchovis, still saltier than herrings. Other ingredients: potatoes, egg, red beet, apple, onion, capern, malt vinegar, lemon juice. And a topping of little mayonaise. I serve it with some of the German Vollkorn Brot (Aldi brand prepacked in aluminium), with slices of tomatoes, and onion rings with bell pepper rings fried in olive oil. And two of the anchovis separate, just for the eye. Peter selected a white Galician wine.
As a starter, about one hour before dinner, I prepared some fried frankfurter wrapped in bacon with slices of fried aubergine. With a can of Dorada beer, local beer of the Canary Islands. Ulric and Peter seem to like it. But it is already 21h: Ulric has tomorrow's dogwatch (tomorrow starts for him 02h). Peter has 8 hours to sleep until 6h.
It is 00h now, 2 hours to go then my watch is over. Our position is 500 miles north of Cabo Orange, the most north point at Brazil's main land coastline, at the border with French Guyana. I am left alone in the cockpit playing some music of dEUS, Mano Negra, Einstuerzende Neubauten, ... it is a nice and quiet evening after our day of squall surfing.
When Ulric takes over watch I will have worked today from 02h until 02h, with just some short naps between 06h and 09h and between 16h and 18h. This makes the 22h - 02h early nightshift the toughest nightshift. But I am rewarded with a 7 hours subsequent sleep until 9h in the morning when (in UTC) here the sun is just rising. The sky is clear, the Milky Way is readily visible, the constellations of Orion, Cassiopeia, Cygnus, shine bright. In the western sky Jupiter lights up the clouds a bit: Jupiter is very bright in this dark night. The moon is in its final stage, tonight, after 00h, it is 16 December and it will be new moon. There are only a few clouds at the horizon behind us. That is where the wind comes from, where occasionally squalls come from. The clouds look harmless: I can see the stars between their underneath and the horizon, which means that they don't rain out. With a SOG of 7 knots and a wind of 19 knots the conditions of two days before and longer ago seem to have returned.
I call it a day.