Getting from there to here
20 August 2016
Bill
As much as we would like to take all the credit for our long voyage across the Pacific, we have had a steady and reliable aid guiding us along. That aid is the multitude of instruments we have to tell us things like: where are we? Are we going in the right direction? How fast are we going? Is there a current? When will we arrive? How's the wind and weather 24, 48 and 96, even 10 days into the future? How does it do all this? Well, you are about to find out!
When I come up on deck (and it's pretty much the same with everyone) the first thing I do is sit down and review the 'data' (yes, our instrumentation screen, aka chart plotter, is located low and requires sitting or kneeling on the deck to effectively read it). There's the map. It shows the boat placed on the correct location on the map. We see the location latitude and longitude, we see the boats direction, the wind direction, and most importantly, we see any other ships in the area. A system called AIS, uses our VHF antenna to receive transmissions from all ships in our area. I think they even relay from ship to ship to extend the area where we can see ships. AIS tells us what ships are within a out 60 miles. It gives the ships name, destination, heading, speed, size and, again, most importantly the closest it will come to us and the time when that will occur in the future. Obviously, we don't want to be anywhere close to one of these huge ships, some 800 and 1100 feet long! Karl and I passed a ship last night within about 4 miles. It was a bit foggy, and at first we couldn't see it, but after a while it emerged, a huge cargo ship far off in the distance going in the opposite direction to us.
Other info on the chart plotter is about the point, or waypoint, we are headed to. This might be a point along our route in the middle of the ocean, or, like right now, 'GG Bridge'. This gives us the name of the way point, the heading to the waypoint, our 'VMG' (Velocity Made Good), the distance and the ETA in hours to the way point. We've been watching this like a hawk for a while now trying to estimate our arrival time. When sailing the ETA changes like crazy with every change in wind speed, boat speed and direction. When we have 900 or 700 miles to go, 0.3 Knot change in VMG results in the ETA changing by days, from say 120 hours to 96 hours. It's very gratifying when a gust of wind speeds up the boat to 9.5 kts and the ETA drops by two days, however the reality is we don't maintain that at all and we use a more reasonable 6 or 7 Kts as an average.
When driving the boat while sailing, we rely very heavily on another related set of instruments that are mounted as a 'heads up' (actually a head down) display. By glancing down, you can see the heading of the boat relative to the wind, the boat speed and wind speed. The compass is also located here. All of these are crucial to good sailing. If we are trying to go a specific compass heading, the instruments tell us if we need to trim the sails. If the wind speed picks up, we may need to depower the sails or reduce sail (reef the sails). If we are sailing to the wind, which is usually the case, every time the wind shifts, or if there's a gust, the boat needs to be steered to take advantage of it; to keep the sails at the same apparent angle to the wind. You need to do this while at the same time steering big swells or around steep waves. And the instruments, including the compass, change values so much, you are constantly averaging them and anticipating the next change. It can be tiring and is the reason we almost exclusively when to 15 minute shifts of steering when in the most challenging, dynamic situations (read high wind, big swell, steep waves).
We have VHF radio for communication with other ships. We haven't used it, but we make sure it's on. We want to hear if anyone is trying to contact us, especially one of those big ships.
The other really important electrical equipment is our Iridium Go and a cool program called Air mail (Sail mail). It's a satellite phone and computer program that provides a connection to a specific server, the sail mail server, dedicated to people like us. The server provides us GRIB files. These are data files that allow us to view on a map what the wind and waves will be in the next week or so in 6, 12 or 24 hour increments. We would look at the map and say, OK, we will be here in 24 hours, the wind will be 12 Kts from the North West and the swell will be 1.5 meters. In 48 hours we'll be over here and, well you get the idea. We also downloaded things called weather faxes. These are old style weather maps like what you might see on a weather forecast. It's done by a National Weather Service weather man and tells us where the high and low pressure systems a are, hurricanes, Gales etc., and where what it will be in 24, 48 and 96 hours. We also get email via the Iridium Go, and I post these blog entries that way. It's been our only connection to the outside world over these last 16 days. 16 days!
Right now: wind speed: 3.5 Kts Boat Speed: 7.6 Kts Heading: 081M Course over ground: 076M Way point: GG Bridge VMG: 7.2 Kts Range: 83.0 nm ETA: 12 Hrs, 14 Min
That's about it. Love you all.
/Bill