The Big Picture

First, the squalls have thinned out, the sun has come out, the wind has come down (12-16), and the seas have gone down. Much more pleasant! Time to reflect a bit on the big picture of sailing to San Francisco from Hawaii. As I mentioned in a previous entry, it's all governed by the North Pacific High. Specifically, the high pressure system which sits in the north Pacific. So first a little primer for those who are as obsessed with weather as I have become. If you already know about the weather systems in the north Pacific, you probably should skip most of this.

A high pressure area is like the top of mountain with a blower on the top from which flows wind. The wind flows down the sides of the high pressure mountain to a low pressure area, just like water. In the process (in the northern hemisphere), it turns to the right (Coriolis effect). So effectively the winds in the north Pacific flow in a clockwise direction around the high. The winds in turn push the water and create the currents to the currents that also flow in a clockwise direction around the high (this is why California gets a cold current from Alaska and Japan gets a warm current from the equator).

Now if you imagine that the high is in the middle of the eastern Pacific (say 1,000 miles west of California), then the wind is flowing down the coast of California, turns right towards Hawaii, turns right again towards Japan, right again across the Gulf of Alaska and another right to return again to the coast of California. A big circle.

We can't sail into the wind, and it's uncomfortable to sail close to the wind for extended periods of time. Our comfort zone is with the true wind about 75 degrees from the bow. Departing from Hawaii, the wind blows a little north of east (think 2:30 on a clock), so we struggle to sail a little bit east of north (maybe 12:30 on the clock). But California is NE (1:30 on the clock), how do we ever get there?

The solution is the circle. Roughly speaking, we sail up the western side to the top of the circle, then across the top so that the wind is helping us. The middle of the circle, or center of the high, has no wind so we actually need to get above it. However in our case we're happy to motor through the center and cut the corner a bit. In any case, this means we travel a lot further than the straight line from Hawaii to San Francisco. I'll be happy if we sail "only" 400 miles further. But the real problem is that the high is moving, shrinking, expanding and sometimes even splitting into two.

At the moment, we're sailing north, trying to go a little bit east (towards San Francisco) and every thing is pushing us west. The wind is from the east (our right) and the boat's hull and keel converts that push to go north, but not perfectly. We have a certain amount of leeway so that even if we're pointed north by northeast, we might actually be traveling north. And then the current is also from the east. The very water we are in is moving to the west so again our actual travel has a more westerly component than where the boat is pointed. And finally, as insult to injury, the squalls bend the wind to the north, forcing us to actually sail west of north at times, away from our goal. So for the first week or so of the trip, all the natural elements are trying to push us west, away from our goal which is to the east. Once we get to the top of the high, the winds will shift to the north or north west and the winds and currents will be pushing us south. So we need to go far enough north that we'll be able to be pushed south and still arrive in San Francisco, not Los Angeles (Hi Caitlin!).

San Francisco's latitude is about 38 degrees north. The high is expected to be centered at about 43N when we reach that area (it's a forecast and it's constantly moving) so we'll probably travel to at least 40N when crossing the high. Then when we emerge from the eastern side of the high we'll have the wind from the north north west and we'll be able to sail a straight line to San Francisco. But it's a little early to start chilling the champagne.

That said, since earlier today the sailing has been quite pleasant and we're making good speed, if not actually a great direction (barely east of north right now). But we'll take nice sailing that is even close to our goal. As Fay would say, "this was in the brochure".