With a partly cloudy sky and no rain in sight we approached the Huatalco pilot station. The peculiar thing was that during the night the current kept increasing. A strong following current, while we were supposed to have a slight current against us. By the time I was lining up for the approach, the ship was set considerably to the East. Not pleasant when you have to enter a bay that keeps getting more and more narrow. When the pilot hopped on board, he brought the exciting news that at the start of the outer bay, the current was going the other way, so even more fun. Now I had to figure out where the easterly current stopped and the westerly current started, without knowing how strong that current was going to be. I discerned a ripple through the water and thus I knew where the first current was ending. With an educated guess I steered more northerly to offset the expected counter current. I had to give more and more current angle (e.g. degrees away from the regular course) and in the end we were drifting under a 30 angle into the bay.
That was a bit of an unusual sight for the guests on the bow, who saw the bow of the ship heading for the rocks and then sliding by at a safe distance. I kept the ship safely in the middle of the fairway but the angle of the ship to counter act the current gave a different idea to the naked eye. While approaching the inner bay where the dock is, the current suddenly disappeared and I could bring the bow back to pointing the regular way where we were going, with the ship following the bow.
Huatalco from the air. The approach is when passing the rocks where the surf breaks on. The outer bay is the area when past the rocks; and the inner bay is where the dock is located.
So we thought that all was now under control; we were wrong again. Although the current was now much less, it bounced through the bay. When the bow came towards the beginning of the pier, it was push to the West, when the bow came to the middle of the pier it was pushed to the East, and when we were nearly in position it was pushed to the West again.
Thus I had to counter attack with the thrusters all the time. We cannot be more than 30 feet from the pier when we are sliding in and 30 feet is not much when the current is pushing you, especially when the stern is the under influence of a different current than the bow. I was able to keep the ship more or less straight while coming in with constant adjustments on the rudders, engines and thrusters but it looked on the Black Box read out, as if somebody had walked home late at night after a very happy party. This was by far the most unusual docking I had ever had in Huatalco.
Still we were happily docked by 09.30 and all could go ashore, half an hour early. The sky was slightly overcast and that kept the worst of the glare of the sun away. One shower came over in the mid afternoon but for the rest it was dry. Huatalco town, just on the other side of the hill got a lot more rain as the clouds somehow bounced off the mountain ridge that surrounds the bay.
Now I had to wonder about departure. On arrival the initial plan had been to swing around and go stern in but with the strong current setting us towards the rocks in the west that was not feasible. Now coming, out the question was, is the current still there and how will it affect me. Thus we sent the pilot boat out to sit on the outer buoy and let it drift, while we watched. The plan was to line the ship up while still in the inner bay, plan for the right drift angle based on the pilot boat observation and then generate as much astern speed as possible to get out of the bay. The faster the ship would go, the less it would drift. In the meantime I can then use the bow thrusters to steer. The pilot boat did not drift that much, which meant that the current must have disappeared during the day. In the end we could back out, without any drift, and stay exactly on our track line.
By 17.30 we were back in open waters and heading for Puerto Chiapas and sailing through the Golfo de Tehantepec. Yes there is a strong wind blowing again but the predictions are less than on previous occasions. I estimate that we will have no more than 45 knots tonight, so with our regular precautions we will be in good shape. Arrival at the Puerto Chiapas pilot station will be a 07.00 hrs andthat is a very decent time to start the day. The challenge there is normally the swell in the entrance, which reduces the depth of the fairway. Hopefully it is not too much.
November 2, 2012 at 12:45 pm
Captain, When “crabbing” as much as 30 degrees from intended course, do you rely on GPS to give you track over the ground or do you pick out a range on shore and keep them lined up?
November 2, 2012 at 7:38 pm
Good morning,
There is a leading light-range for the bay entrance that can be used for reference but the GPS input on the Radar/electronic chart also gives the drift angle/arrows which shows the true driection of the ships movement. Both together gives a pretty good idea of where the ship is exactly located and where it is going. The third thing that we use, is looking out of the window and observing how fast a buoy or something else -fixed- moves in relation of the ship. When it accelarates or de-accelarates in relation to the ship, we know whether current is increasing or decreasing. The naked eye is most often faster in the pick up of a change than the sattelite input.
Thank you for reading my blog
Capt. Albert