Sunday, October 10, 2010

Stella Polaris

First Published September 11, 2006

I disembarked from “Fayal Cement” after passing abreast of the fairway buoy and proceeded to “Stella Polaris”. She was coming from the North and I could not see her until we were at about 5 cables due to the fog, although I was tracking her through the pilot boat radar.
I boarded the vessel and recognized the captain from previous voyages. I presented him the pilotage passage plan and he explained me the vessel’s characteristics. We didn’t loose too much time with this as I already know the vessel and the captain already knows the port, so I just draw his attention to the prevailing port conditions, like the expected traffic, wind and tidal current, under keel clearance, and how I was planning to take the vessel alongside.
By the time we were at about 2 cables from the breakwaters the visibility improved a lot and as the captain is familiar with the passage I just told him to steer in the middle of the channel.
On the last pair of buoys I took the con and started positioning the vessel in order to go starboard side alongside. I ordered slow astern to take some speed off and used the bow thruster half speed to starboard to approach the bow and pass a spring line ashore. The combined effect of the side thrust of the propeller (acting like right handed) and the tidal current on the starboard quarter started swinging the vessel across the river making an angle to the berth that would make it impossible to bring the stern alongside.
I immediately decided to go for an alternative manoeuvre that I use when the current is astern (which I had underestimated because it was a neap tide). I ordered hard to port the wheel, bow thruster full to port, and gave a kick ahead in order to swing the vessel rapidly to port, to put the tidal current on the port quarter. Once I had the current on the port quarter I started coming astern to the berth, steering with the bow thruster. With the vessel making the proper angle with the river the tidal current acts like a “silent tug”, helping to berth the vessel. Also, when the vessel is going astern the pivot point also moves astern enhancing the effect of the bow thruster. In this way I just had to approach the stern of the vessel to pass a sternline and then, using the bow thruster, paralleled the berth.
I enjoy this kind of manoeuvre (as long as the bow thruster has enough power to compensate the side thrust effect of the propeller) because you take full use of the bow thruster and always have the possibility to correct the positioning of the aft section by giving a kick ahead with the rudder full to either side. Nevertheless most captains feel uncomfortable with this “going astern” to the berth, whether because not used to it or not trained to do it. In this particular case, we had already done it so it was not a surprise to the captain, which knows we can’t swing and go portside alongside on this berth.
Naturally I could have used the tug boat that was standing by (compulsory for tankers), but that wouldn’t be half the fun…
After the vessel was safely moored with 3 headlines and 2 springlines forward and 3 sternlines and 2 springlines aft I disembarked to the pilot boat and went back to the pilot station to finish the paperwork and prepare the next manoeuvre.


Manuel said...

Caro Daniel M. Vale, ainda bem que este pilot boat voltou às manobras.

L D Malheiro do Vale said...

Amigo Manuel,
Infelizmente sem muito tempo disponível, resta-nos re-publicar antigos posts e fazer uma ligeira modernização no layout, afinal já lá vão 4 anos...