A most impressive demonstration of seamanship

[Craig Harlamoff]

Last night I was sitting in the upper deck of the San Francisco Giants baseball park watching the game. I looked out upon the SF bay and saw the most unusual site. A giagantic oil tanker making it's way to the south bay anchorage towing a large tug boat backwards. mmmmm, backwards? Then I saw the nearby Coastguard cutter and pilot boat. I realized the situation, The oiltanker had lost it's steering and the tug being towed was being used to steer the ship. Sure enough, from time to time, the smoke would pour out of the tug and it would move to one side or the other, pulling the stern from side to side to steer the ship. I've heard of boats dragging a drogue from one corner or the other to steer the boat. I've never seen an oil tanker dragging a ocean going tug. Considering the size of the oil tanker and tug, I was greatly impressed. One mistake and the tug could have been pulled under and the oil tanker could have careened into the Oakland estuary.

At the anchorage location, the ship slowed, dropped it's anchor and the tug pushed the stearn around so the bow was into the wind. I was very impressed.

Oh yes, the Giants clobbered the Marlins and we watched Barry hit 716 out of the park. Sweet.

[Alan Wheeler]

It's actually quite a normal operation. These ships simply can't steer in a confined waterway. Some of the really big tankers take a mile or more to turn. So the tug actually pulls or pushes the ship around. I know the Tug looks small, but dont let that fool you. Those things have some scary hp onboard and can push a big ship around.

[CaptainJeff]

I think we all understand what a tug is for.

Alan, are you saying you doubt the ship's steering was damaged? The presence of both the pilot and the Coast Guard suggests there was something out of the ordinary; and after all, Craig was an eye witness to the events.

The captain of the aforementioned ship is very happy with his new stern thruster, by the way.

[JohnWms]

Almost all of the big ships that come into Commencement Bay (Tacoma, Wa) have a Coast Guard escort at some point. They'll run you off if you violate the minimum distance requirement too. They also have a tug at the bow and stern as described when operating in restricted water.

Even though it is standard operating procedure it is none the less very good seamanship.

[Alan Wheeler]

No Jeff, I wasn't saying that at all. It would be foolish for me to suggest such without knowing the true picture and knowing the harbour laws and blah blah. What I am saying however, is that the Tug operation witnessed is quite normal the world over.
I could also imagine with your security issues, that a fuel tanker would be something that would be well guarded by CG.

[CaptainJeff]

Thanks, Alan, appreciate that clarification.

[Craig Harlamoff]

I've mentioned this on other SF forums and they verified that it's common for high risk ships to tow a tug backwards. Wow, I learned something.

[sailfish]

I'd be willing to wager that the tug was a tractor tug which is designed to operate 360 degrees. So, although the tugs was going backwards, they are designed to operate backwards, forwards, sideways, or whatever. The propulsion is in the center of the vessel.

[Alan Wheeler]

Yeah and it's the most wierdest looking propulsion device you could imagine. If anyone could actually explain how that strange looking unit under them works, I would be real happy.

[GordMay]

A “Tractor Tug” is designed to pull from (or push with) its stern. These tugs have the ability to direct their thrust through 360 degrees of azimuth (without a rudder), and have the propeller units located forward in the hull and tow point at stern of the tug so that the propulsion is forward of the towing bollard and ahead of the axis of vessel rotation (towards the bow). These tugs are able to turn in their own length, and often apply the same amount of power in virtually any direction
Google: “Voith Schneider” for more info’

[markpj23]

During my stint as Officer In Charge of the US Navy research facility in Ft Lauderdale, we had a 160+/- foot ship with 3 Voith Schneider units. They allow exceptionally precise manuevering and station-keeping ability. The ship was primarily used for underwater construction and had a "moon pool" amidships where we could remove the deck hatches and have a calm water surface area protected by the hull on 4 sides. One time when the crane cables going down through the moon pool twisted and fouled the sheaves we spun the ship and removed the twist while remaining in position above the fixed load on the bottom. Try that with twin screws and a bow thruster!!

When the VS drives went bad on occasion, the factory representative would require that everyone leave the machinery space while the unit was open. Very secretive about the internals of the units.

Great for precise thrust direction but slower than a Taiwan Turkey beating into the wind while travelling in a straight line.....

[CaptainK]

Mark.

What job/rate where you in during your time in the US Navy?

Where you a oceanographer?