Do many Ships breakaway from the dock ?

[biker@sea]

http://boston.cbslocal.com/2017/12/06/container-ship-breaks-free-boston-terminal/

 

One snaped 12 line's before drifting into Boston Harbor today.

I do think NCL Star Brokeaway in Bermuda once.

Then hit a Royal ship too.

[chengkp75]

It happens. Especially if the winds come up suddenly. Though typically the winch brakes are set to "render" or slip before the breaking strength of the lines. This gives the crew time to power up and pull the lines in again, get a tug to push into the dock, and get more lines out, while the ship slowly moves away from the dock with the lines still attached. It can even happen in certain ports where a ship passing too close to a docked ship creates some "canal effect" and sucks the docked ship off the pier.

[easyboy]

It happens. Especially if the winds come up suddenly. Though typically the winch brakes are set to "render" or slip before the breaking strength of the lines. This gives the crew time to power up and pull the lines in again, get a tug to push into the dock, and get more lines out, while the ship slowly moves away from the dock with the lines still attached. It can even happen in certain ports where a ship passing too close to a docked ship creates some "canal effect" and sucks the docked ship off the pier.

Interesting! Would the canal effect be regardless of weather condition?

[chengkp75]

Interesting! Would the canal effect be regardless of weather condition?

 

Yes, canal effect is also known outside the maritime world as "venturi effect". When the water is shallow, the motion of a ship can cause a low pressure in the narrow waters between the vessels. This low pressure draws the docked ship off the pier. Typically, when a ship is going up a channel, or the Miss River, the pilot will slow down when approaching docked ships for this reason.

[biker@sea]

We had a near flood 13' tide's with the passing super full moon too.

[chengkp75]

We had a near flood 13' tide's with the passing super full moon too.

 

Tides are usually not a problem unless in a constricted waterway where the flow velocity is increased. I really haven't checked where the dock in question is, but I know where the container docks in Boston are, and they really aren't in an area where flood or ebb tide currents would be that great.

[paul929207]

We had the opposite problem. Strong winds in Sidney Nova Scotia pushed us against the dock, so we could not sail. We had to wait overnight for a tugboat to come up from Halifax to pull us off the dock.

[Keith1010]

Not very often.

 

Keith

[Clarea]

Rare.

[Lady Chew]

Date: Tuesday, 10 October 2017

Port: Huatalco, Mexico

Ship: Nieuw Amsterdam

We were on a shore excursion at the time this happened ... a sudden storm with high winds came up suddenly in the port, the aft ropes snapped, and the ship was pushed onto a sandbar. No one could get on or off the ship for a few hours, so hundreds of passengers were stranded by the shops - which had no electricity due to the same storm. We finally got off the sandbar, but had to wait while a visual inspection of the hull was conducted.

In order to keep the divers safe, the controls to whatever is down below to propel & steer the ship had to be completely turned off so that they couldn't accidentally be turned on when the divers were below. Once the divers were done, it took an hour or so for the controls to come back on line. Obvioulsy we were late leaving the port!

Some time later in the cruise, I think in Aruba, divers went down again for a more detailed inspection, but time in port was not impacted.

[GUT2407]

We had the opposite problem. Strong winds in Sidney Nova Scotia pushed us against the dock, so we could not sail. We had to wait overnight for a tugboat to come up from Halifax to pull us off the dock.

2014 similar in Melbourne on of the Princess ships Diamond I think, couldn’t depart as the winds had her pinned, we had to divert across the Bass, in gale force winds, a rather rough crossing.

[donaldsc]

We had our ship pinned against the dock in FLL by winds. We couldn't even get out with the help of tugs. Instead of departing at around 6 PM, we did not depart until late at night.

 

DON

[Krazy Kruizers]

Many years ago on the old Royal Princess, the winds were so bad that we could not get away from the dock in Stockholm. It took a couple of hours until the winds died down.

In 2000, we were on the Zaandam in Cozumel when a line being tied off and snapped. We were out on our verandah when the ship jerked and the snapped line went zooming past us. The ship was only a month old so the lines were not that old.

[Capt_BJ]

as a sailor trained to military standards, every time I see how the average cruise or merchant ties up I shake my head. Seems WAY under done IMO. To wit, I've never heard of a Navy or CG vessel blown off the pier, yet can cite many cruise ship and merchant incidents. It happens ......

 

Not too many years ago a storm kicked up in Canaveral and blew a Disney ship off the pier. The gangway fell down and tugs had to respond rapidly to push the ship back to the pier. Fortunately boarding had been stopped as the storm came in so no one was injured.

 

Another issue is the failure of the shore infrastructure ... those 'bollards' where ships attach their lines are sometime not as strong as people think. A few years ago a Carn' ship undergoing repairs in NOLA (after one of their spectacular loss of all power incidents') was blown off the pier when the pier bollards failed during a storm with strong winds ... they ripped off the pier allowing the ship to drift away ..... saw this at a CG base when a ship was mooring. They attached the bow line to a pier bollard and took tension to warp in .... and the bollard broke off at the base!

[chengkp75]

A couple of differences between the military ships and the merchant ships is the crew size to handle all the lines. The other is for cargo ships (not so much for cruise ships), where the draft is constantly changing, and therefore the lines need to be tightened or slacked every half hour or hour. If the ships deployed extra lines (and we do sometimes at the terminal's requirements) that had to be belayed to fixed bitts instead of to the mooring winch drums, this increases the amount of crew needed to handle these lines, and increases the risk to the crew for accidents.