It has been a while since we’ve done a passage in which the weather risks held the potential for unpleasantness. The distance between Cape Spencer (the northwest corner of Southeast Alaska) and the entrance to Prince William Sound is just 345 nautical miles but the sea bottom, currents, and "weather factory" off the Aleutian Islands demand careful planning and respect.

Wind Horse can average 11 knots in virtually any conditions, so the time frame we are looking at is around 33 hours. However, we want an additional allowance for a mechanical problem which might slow us down, and a factor of safety in case the weather forecasters make an error in judgment.

There is also the state of the tides and currents to consider. Strong ebbing current at the entrance to Prince William Sound can set up breaking seas when they oppose southerly quadrant gales. So, we are aiming for the last of the ebb current or beginning of the flood.

One of the factors determining the amount of time between yourself and weather risks is the direction of travel relative to the weather. Most weather systems move from west to east, which is the case here as well. Since we are headed west-northwest, we are on a collision course with weather coming our way.

On the other hand, the weather we will be concerned with is generated by low pressure systems. The winds around these lows rotate counterclockwise (the opposite is the case in the Southern Hemisphere), so the leading edge winds are easterly quadrant (northeast to southeast). This means the wind and wind waves are going to be behind us.

We begin getting ready for the trip by monitoring the surface and 500mb weather data a week in advance. This gives us a feel for the rhythm during the current season. The past couple of weeks have seen an unusually stable high pressure system holding off the usual low pressure cells and associated fronts. The most conservative thing to have done weather wise was to use this high for the passage. But we’ve been seduced by the weather here in Southeast Alaska, and now Mother Nature is back to her normal pattern.

We have a weather fax aboard, but these faxes have all been downloaded from the Internet, using our Verizon broadband modem on the PC, which has been working even in Icy Straits (and as far as 20 miles northwest of Cape Spencer). The chart above is the current situation. The passage will take place just below the "H" at the top and just off center to the right of the image. There is a weak 992mb low centered south of the Aleutian Islands, which is what will dominate our weather.

If you are used to looking at temperate climate lows, this looks like a really steep pressure gradient, with the potential for a real blow. However, the further away from the equator you are, the more gradient it takes for a given amount of wind, and up here, close to 60 degrees north, this is considered a weak pressure gradient.

This is a portion of the current 500mb chart (lots more on 500mb data will be found in Mariner’s Weather Handbook). This shows us the last of the high over our area, and a matured upper level trough to the west – none of which hold risk factors for our current passage.

The 500 mb chart above is for 48 hours from now. Overall, this does not look bad, at least for a passage taking a maximum of two days. In fact, the moderate following winds will give us a nice push. The fact that it might be chilly and maybe a bit damp is no longer a concern (one of the benefits to cruising on an Unsailboat). So by 1000 we have Cape Spencer off our starboard beam, with the bow pointed towards new territory.

Here is a vista not often seen in this part of the world. The Fairweather Mountains are usually hidden in clouds.

These mountains include a series of large glaciers.

Mount Fairweather, at 15,340 feet is the highest peak we’re likely to ever see from the deck of Wind Horse.

If you watched the Discover Channel series on commercial fishing in Alaska, or read much about this part of the world, the Fairweather Grounds will be etched into your memory. These are extremely rich fishing grounds. They are like a high mountain plateau, just a few hundred feet below the surface of the ocean, rising precipitously from the sea bed (depths on the chart above are in fathoms).

This is a photo of the depth track from our SONAR. We have gotten in the habit of leaving this on as a double check of our position against the depths shown on the chart.

These vector chart depths are in feet. Note how quickly it goes from 8000 to a couple of hundred feet. Then imagine yourself in a real blow, with large open ocean waves suddenly encountering this almost vertical undersea wall. Throw a variety of confused currents into the mix. Chaotic sea state is the result. If the weather were other than benign we’d be well out to sea rather than crossing this shallow area on the rumb line.

The weather is staying as predicted, and winds are from the east to southeast, at 8 to 14 knots. The barometer is dropping half a milibar per hour, not that bad for 60 degrees latitude. We are watching the weatherfax, logging the barometer and weather data, and keeping an eye on the sky. All signs point to continued fair winds. Our two booms are deployed to add windage in this following breeze.

We are also picking up NOAA weather on the VHF out of Yucatat. They provide detailed local and offshore information. And it is being read by humans rather than the usual computer voice – a pleasant change.

Although we are almost a month from the summer solstice, it is still light enough at 2300 to watch for debris. And we’ve got light again by 0400.

The approach to Prince William Sound requires a degree of watchfulness, starting with Cape St. Elias. There are the usual navigational issues, along with ships to be avoided. We are also more likely to encounter logs close to shore (and in fact we hit two, glancing blows, at different times). The radar (on the right above) has a target setting up to pass us on our starboard side. You can see Cape St. Elias ahead, while the bottom is coming up quickly on the sonar depth screen (left).

We’re almost there. Hitchinbrook Island and the entrance to Prince William Sound are just ahead. We are on the edge of the traffic separation channel.

The low that used to be well to our west is now a lot closer, and we’ve got a thick deck of clouds with intermittent rain showers.

We also have this 950-foot (285-meter) tanker overhauling us to port.

And we are happy to see that the local chamber of commerce has sent out a welcoming committee. Lots of humpback whales at the entrance to Prince William Sound bid us hello.

1620 local time, the anchor is down in Comfort Cove on Hitchinbrook Island, 32 hours after departing the Cape Spencer area. We’ve averaged 11.5 knots for a very pleasant passage. So ends this voyage.

Post Script: We’re sitting at anchor surrounded by snow-capped peaks, with eagles, sea otters, and whales plying their trades close by. This is just 33 days since leaving Southern California, ten of which were spent doing maintenance projects in Seattle. So, 23 days cruising to get to Prince William Sound, with four nights spent underway. If this sounds quick, along the way we have had time to visit with friends and enjoy wonderful anchorages. We’ve been able to take advantage of good weather when it presented itself to move comfortably and quickly to the north.

There are several keys to this. One, Wind Horse’s ability to average 11 to 11.5 knots in all conditions. Second is to have a firm goal – in our case this starts with Prince William Sound. Third is to press on when conditions are favorable, even when we’d rather just hang out for a while.

To take advantage of weather opportunities, you have to recognize them when they present themselves, which is why we think understanding weather is the single most important cruising skill.

Having arrived at our summer’s destination, we are going to slow down.