Monday, September 21, 2009

“That’s a Roger there Coast Guard motor lifeboat, our bilges are empty, we are not taking on water and we are not on fire!"

We had a decent run down from Crescent City in 25 kts until about noon when the wind decreased to 15kts. Unfortunately the sea was still so lumpy that even with 15kts of wind our sails would manage to backwind, bang and slat with every wave. But for the most part, we had a pleasant sail and added another 60 NM of wake behind us before arriving at the Humbolt bay entrance where we were abruptly shut down from entering the bay.
The harbors along the west coast of the US are particularly dangerous places because many of them are placed in the mouth of a river. One would think that you could just simply leave the ocean with all its waves and enter the stream of the river. Unfortunately no! Each one has a “bar” in front of it, which can only be crossed at certain times in favorable conditions. Think of a typical ocean beach with waves crashing on it. As a wave enters from deep water into shallow water, it begins to interact with the ocean floor and gets pushed upward and slows down. To an observer on a beach, the wave becomes noticeably larger and the frequency of waves increases (more waves together). Now back to the river, most rivers carry much sediment and when they hit the ocean, they deposit this sediment at the mouth. This sediment deposition is what causes a shallow area, the bar, that must be crossed to enter the river. Further, to complicate matters, the flow of water out of the river is usually contrary to oncoming ocean waves. These two opposing currents further act to both increase the wave height and frequency and can result in breaking (surf like) waves that could easily capsize a boat. Therefore the safest time to enter is during the rising (flood) tide when the ocean waves and the rising tide water are traveling in the same direction, up the river. The result is usually smaller waves that are not breaking and hopefully a smoother ride in. To make things a little safer, the entrance channels are routinely dug out (dredged) to make them of consistent depth and one must follow these channels with little deviation in order to stay out of the breaking waves. Does this sound complicated yet? Well, in order to determine where the channels are, there are a series of shore-based transit lights that are only aligned when you are in the correct location.

Now unfortunately yesterday the flood tide began after dark and so we had to wait until dark to enter. Now combine these channel navigation lights with all of the city and radio tower lights in the background of the city you are entering, add a heaping of 12-foot waves and a little fog in the dark and what do you get? A call to the Coast Guard for an escort in to the harbor! We called, they came and guided us in through to entrance and into the correct channels and even right to the dock that we wanted. They even lit up the docks with a spotlight until we had moored safely. They then came aboard, did a safety check, and gave us a clean record. Overall they were a fun bunch of guys, so nice and provided such a great service. I admit, that of all the places we have been, as remote as they were, last night was potentially the most hazardous and I was sure glad for the guide in.
We are now in Eureka, California and are experiencing a heat wave. There are also more palm trees all over now. Getting closer.


1 comment:

  1. Don't go swimming at the river outlet's either, that's where the big great white's are lurking....

    O Al