Port Speed

[golfb4cruzing]

I enjoy watching ships come into the port areas via webcams. I was watching the Disney Wonder come into Nassau this morning and again noticed a difference in approach speed of Disney ships. Hopefully Chengpk75 can shed some light on some specifics. Are the Disney ship better equipped for maneuvers ? They seem to enter the port area quickly and then their 180 turns are quicker as well. Thanks for comments and info.

[donh1]

Just my opinion but I think it depends on the captain. Most captains go slow with caution because one serious error could end their career. Having said that we were on MSC Poesia a few years ago and he drove it like a speed boat.  His background was with cargo ships so I assumed he was very comfortable with how the ship handled......

[cherylandtk]

I thought the local pilot was in charge at these times.

[golfb4cruzing]

I do see the Pilot boat drop off but still a marked difference

[chengkp75]

The pilot "has the conn" (is giving the orders) while entering port, so it may be a difference between pilots.  The Disney ships are all prop/rudder (non-azipod) ships, so the pilots will be more familiar with these ships, even given the number of azipod ships the pilots in many of these cruise ports handle.  Azipods react differently when reversing (going to zero speed, azimuthing the pod 180*, then ramping up the speed) than a propeller with variable speed/variable pitch like the Disney ships (basically the prop stays turning at the same speed, but the propeller pitch reverses), so pilot handling will be different.  Then, azipods can be rotated to athwartship to spin the ship, along with the bow thrusters, while the Disney ships will use bow and stern thrusters, and if the pilot is skillful, they can "split" the propellers (one ahead and one astern), and use the "high lift" Becker rudders to act as large thrusters, much like the azipods.  Where the pivot point of the ship is (one third from the bow when moving forward, one third from the stern if moving astern, or midships if stopped) will also affect how the various systems (thrusters, pods, or props/rudders) work to spin the ship.

 

I don't think the Disney ships are any better equipped, each type of propulsion has its benefits and drawbacks.

[donaldsc]

45 minutes ago, chengkp75 said:

The pilot "has the conn" (is giving the orders) while entering port, so it may be a difference between pilots.  The Disney ships are all prop/rudder (non-azipod) ships, so the pilots will be more familiar with these ships, even given the number of azipod ships the pilots in many of these cruise ports handle.  Azipods react differently when reversing (going to zero speed, azimuthing the pod 180*, then ramping up the speed) than a propeller with variable speed/variable pitch like the Disney ships (basically the prop stays turning at the same speed, but the propeller pitch reverses), so pilot handling will be different.  Then, azipods can be rotated to athwartship to spin the ship, along with the bow thrusters, while the Disney ships will use bow and stern thrusters, and if the pilot is skillful, they can "split" the propellers (one ahead and one astern), and use the "high lift" Becker rudders to act as large thrusters, much like the azipods.  Where the pivot point of the ship is (one third from the bow when moving forward, one third from the stern if moving astern, or midships if stopped) will also affect how the various systems (thrusters, pods, or props/rudders) work to spin the ship.

 

I don't think the Disney ships are any better equipped, each type of propulsion has its benefits and drawbacks.

 

You say that the pilot "has the conn" while entering port.  I had thought that except for the Panama Canal where the pilot has full responsibility for driving the ship, the captain has the responsibility in all other ports.  If he is smart, he will obviously follow the suggestions of the pilot but he does not have to.

 

Do I have it wrong?

 

DON

[chengkp75]

1 hour ago, donaldsc said:

 

You say that the pilot "has the conn" while entering port.  I had thought that except for the Panama Canal where the pilot has full responsibility for driving the ship, the captain has the responsibility in all other ports.  If he is smart, he will obviously follow the suggestions of the pilot but he does not have to.

 

Do I have it wrong?

 

DON

There is a difference between having "command" and having the "conn".  The Captain can relinquish his authority to control the ship to an officer who has the "conn", but cannot relinquish his responsibility for the ship.  Just like when at sea, the Captain relinquishes the "conn" to the various bridge watch officers (the Captain is not on the bridge 24/7, and there are course changes and vessel crossings to accomplish during a given bridge officer's watch), when using a harbor pilot, the Captain relinquishes the conn to the pilot.  The pilot, as he is not a company employee, is not allowed to handle anything on the bridge, he can only give orders (if granted the conn) to the bridge crew who will do the actual steering, propulsion telegraph orders, operate the thrusters, and the pilot cannot even adjust the range setting on a radar without asking permission.  Whether the ship is being "conned" by a harbor pilot or a bridge officer, the Captain has the authority to assume the conn at any time.  This is one of the problems that happened with the Concordia, there was no official notification (verbal announcement) that the Captain had assumed the conn, even though he started giving orders.  This leads to confusion in the bridge team.

 

In the Panama Canal (and the other instance that most folks don't know about, when a ship crosses the "sill" entering a dry dock), the Canal Authority assumes full financial responsibility for the vessel, so in those instances the Captain relinquishes his authority to the pilot.

[Capt_BJ]

had to do a lil digging to verify but unless they've been changed since original construction, M and W had fixed pitch screws, not controllable.  I got suspicious for two reasons

 

1) watch the video of when one of them hit the mooring dolphin in Nassau recently.  All my ship driving experience is with controllable pitch and with this system you don't have much delay when shifting thrust direction (an advantage of the system at the cost of COST and 1000% increase in system complexity)

 

2) When M & W did drydocks in Norfolk, the dock was right outside my office window and driving to work I'd get a few hundred yards from the rear-end of the ships.  Saw the screws and hubs and know a fixed from a controllable system

 

but did do some research to verify. Dunno about F & D but the first two are very 'traditional' propulsion with diesel electric powering 2 shafts with fixed pitch screws. There are bow and stern thrusters of course ... and twisting a twin screw twin rudder ship in its own length using only the engines and rudders is not rocket science .. rather a basic skill IMO. One I knew my new deck officers learned ....

 

****************

wrt to speeds ..... I'm sure there are maximum speeds mentioned for some ports altho I can't remember this ever being a factor in my arrival/departure planning.  What IS important and discussed at length in the 'Rules of the Road' for ships is safe speed.

 

The rules state: "Every vessel shall at all times proceed at a safe speed so that she can take proper and effective action to avoid collision and be stopped within a distance appropriate to the prevailing circumstances and conditions."  It goes on to list a set of factors which "shall be among those taken into account".

 

It should not be surprising to hear that some ships are a wee bit more maneuverable (including ability to stop) than others. Mine were "high power & big rudders" vs displacement which means maneuverable). A large container ship or LARGE oil tanker is at the other end of the scale and seldom MOVES in many ports without tugs ready to assist and modern cruise ships are somewhere in between.  My safe speed as compared to that of OASIS is different.  Sliding to the next point ... the pilot is usually the one who recommends the safe speed.  The Master/Commander exceeds this at a certain degree of risk!

 

Most port will warn that speed must not produce a wake ... especially one that causes damage to other vessels.  See the many videos of ships 'hardly moving' but their prop wash destroying vessels near by!

 

***********************

 

PILOT: I've commented on this extensively in the past, search for my posts if you want the long details.  I short, I've felt that a course in 'dealing with pilot' is a valid subject for deck officer training.  What a pilot is supposed to do, is legally authorised to do, and DOES are different things. In the US, if a pilot screws up or breaks the rules there are paths to follow to address the problem.  In the islands?  Depends on the island! (and I'd mention I had many problems with pilots in USVI who supposedly operated under US rules ... but I digress).

 

B4 9/11 I enjoyed multiple invites to the bridge on M & W and usually the pilot just sat back and let the Master drive.  The pilot knew the Master was coming in weekly or twice week and did not need much advice - but the law there <as elsewhere> requires a pilot be on board so he was .... had a cup of coffee, collected his fee and waved bye. Never opened his mouth wrt to 'navigational assistance.'  This is an extreme but not unusual.

 

************

there's a different view from the Captain's chair ......

 

******************

Edit wrt to Concordia - standing orders on the ships (Cutters) I served (and Commanded) said once the Captain issues ONE engine or rudder command EVERYONE on the bridge is to loudly announce "The Captain has the CONN"  .... altho personally I made it a habit to announce first "Captain has the CONN" to avoid cornfusion.  I did this in a few occasions where juniors "under instruction" had gotten to a point I thought might get ugly ... and to avoid the 'incident' appearing on their record I tried to step in 'just in time'. 

Edited December 30, 2018 by Capt_BJ

[bob brown]

1 hour ago, chengkp75 said:

There is a difference between having "command" and having the "conn".  The Captain can relinquish his authority to control the ship to an officer who has the "conn", but cannot relinquish his responsibility for the ship.  Just like when at sea, the Captain relinquishes the "conn" to the various bridge watch officers (the Captain is not on the bridge 24/7, and there are course changes and vessel crossings to accomplish during a given bridge officer's watch), when using a harbor pilot, the Captain relinquishes the conn to the pilot.  The pilot, as he is not a company employee, is not allowed to handle anything on the bridge, he can only give orders (if granted the conn) to the bridge crew who will do the actual steering, propulsion telegraph orders, operate the thrusters, and the pilot cannot even adjust the range setting on a radar without asking permission.  Whether the ship is being "conned" by a harbor pilot or a bridge officer, the Captain has the authority to assume the conn at any time.  This is one of the problems that happened with the Concordia, there was no official notification (verbal announcement) that the Captain had assumed the conn, even though he started giving orders.  This leads to confusion in the bridge team.

 

In the Panama Canal (and the other instance that most folks don't know about, when a ship crosses the "sill" entering a dry dock), the Canal Authority assumes full financial responsibility for the vessel, so in those instances the Captain relinquishes his authority to the pilot.

But even in the Panama Canal, the canal pilot does not actually handle the control's of the ship, correct?   Only those trained and employed by the ship line can do that, right?

[chengkp75]

3 hours ago, bob brown said:

But even in the Panama Canal, the canal pilot does not actually handle the control's of the ship, correct?   Only those trained and employed by the ship line can do that, right?

That is correct.

[chengkp75]

3 hours ago, Capt_BJ said:

 

2) When M & W did drydocks in Norfolk, the dock was right outside my office window and driving to work I'd get a few hundred yards from the rear-end of the ships.  Saw the screws and hubs and know a fixed from a controllable system

 

but did do some research to verify. Dunno about F & D but the first two are very 'traditional' propulsion with diesel electric powering 2 shafts with fixed pitch screws. There are bow and stern thrusters of course ... and twisting a twin screw twin rudder ship in its own length using only the engines and rudders is not rocket science .. rather a basic skill IMO. One I knew my new deck officers learned ....

 

You're probably correct about the earlier ships being fixed pitch, I was working off rough notes, but even then, they are electric propulsion, so there is very little delay in reversing, compared with a diesel propulsion drive, where you have to shift the cams, stop the engine, and restart it in the opposite direction.  The electric drive system will have "dynamic braking", where the propulsion motor becomes a generator, actually feeding power back to the electrical system, and since there is no motive force to power this generator, it slows rapidly, the whole idea behind dynamic braking.  And then the switching of the direction of the rotation of the electrical field which controls the direction of the motor's rotation, is electronic, so switching off, braking, and switching back on is very rapid.

[golfb4cruzing]

19 hours ago, chengkp75 said:

The pilot "has the conn" (is giving the orders) while entering port, so it may be a difference between pilots.  The Disney ships are all prop/rudder (non-azipod) ships, so the pilots will be more familiar with these ships, even given the number of azipod ships the pilots in many of these cruise ports handle.  Azipods react differently when reversing (going to zero speed, azimuthing the pod 180*, then ramping up the speed) than a propeller with variable speed/variable pitch like the Disney ships (basically the prop stays turning at the same speed, but the propeller pitch reverses), so pilot handling will be different.  Then, azipods can be rotated to athwartship to spin the ship, along with the bow thrusters, while the Disney ships will use bow and stern thrusters, and if the pilot is skillful, they can "split" the propellers (one ahead and one astern), and use the "high lift" Becker rudders to act as large thrusters, much like the azipods.  Where the pivot point of the ship is (one third from the bow when moving forward, one third from the stern if moving astern, or midships if stopped) will also affect how the various systems (thrusters, pods, or props/rudders) work to spin the ship.

 

I don't think the Disney ships are any better equipped, each type of propulsion has its benefits and drawbacks.

Thank you for the in depth answer. I appreciate your time. Thank you.

[golfb4cruzing]

Thanks to all for the vast knowledge shared.

[Heidi13]

On 12/30/2018 at 6:23 AM, golfb4cruzing said:

I enjoy watching ships come into the port areas via webcams. I was watching the Disney Wonder come into Nassau this morning and again noticed a difference in approach speed of Disney ships. Hopefully Chengpk75 can shed some light on some specifics. Are the Disney ship better equipped for maneuvers ? They seem to enter the port area quickly and then their 180 turns are quicker as well. Thanks for comments and info.

While local port regulations dictate max speeds and collision regulations outline "Safe Speed" the other variables are the cruise line Bridge Procedures and the Captain's level of risk tolerance and customer service v's on-time performance.

 

In my experience, while in pilotage waters, the pilot must be aboard and may have the con of the vessel during the approach, but the docking these days is normally performed by the Captain, Staff Captain or a Deck Officer. However, in some ports the pilot is not even given the con.

 

Back in the 70's I recall some of the bolder Captains performing powerful arrivals/departures, but lately I find most cruise ship dockings very sedate, with minimal vibration. This compares to my last command, which was a large 2,000 passenger Ro/Pax on a 2 hr schedule. We had loads of power and large high-lift rudders. While the approach speed was not excessive with the ability to stop, our swing into berth used a fair bit of power. Everyone on board knew the vessel was docking. Our dockings were 6 to 10 minutes, whereas a cruise ship Captain would probably take at least 20 minutes, but with significantly less power and vibration. If the Disney Captains are spinning the ships faster, they must be using more power, which would normally create more vibration.

 

With respect to Bridge Team Procedures on commercial ships, especially cruise ships. When I started at sea, the Marine & Airline industries had similar Bridge/Cockpit models, where the Captain was never questioned. These days are now long gone, with the airline industry leading the marine industry. Many companies have developed or are developing Bridge Team Command & Control procedures, which are incorporated in a Level 2 Fleet Ops ISM Manual. They generally include 2 or 3 operational criteria - red/green or red/yellow/green. Each criteria has a minimum Bridge Team Manning, which on the lowest level (green) includes a Navigator & Co-Navigator and on the highest level red includes the Navigator/Co-Navigator, with additional officers/cadets for communications and the Captain/Staff Captain overseeing the operation. The pre-briefing clearly states with officer performs each role. The Navigator has the con, monitoring the navigational progress, issues conning orders and receives input from others. The co-nav monitors every action and confirms the desired effect. Both Nav & Co-Nav discuss upcoming changes and agree in advance. The Captain/Staff-Captain oversees the operation, looking at the big picture. The Captain/Staff Captain can offer suggestions or even issue direct orders to the Navigator without assuming the con. However, if the situation required the Captain to issue an order, most Captains would probably assume the con. When the con is changed, everyone on the Bridge must verbally confirm.

 

These procedures were established by Princess/Cunard many years before Concordia and they built a simulator to actually train Bridge Teams. Post Concordia, I believe all Carnival brands have introduced similar procedures. I also received a copy of the RCI procedures and believe most, if not all, major cruise lines operate a similar system. Many of the procedures are developed based on Human Factors and Risk Assessment training. 

 

On many ships, the Bridge Team Command & Control has expanded to the Engine Room, who have similar procedures and manning levels. Whenever one location changes, the other location matches the level. If the engineers experienced an issued and went to "Red", the Bridge would also change to "Red".

 

 

[chengkp75]

2 hours ago, anzore said:

My very good friend is a bar pilot here in San Francisco.. I have been told that each ship has a different way of steering , so there is no way a pilot can know all the different steering mechanisms. They instruct how to bring the ship in. They physically do not take the helm.

I wouldn't say there are different "ways" of steering, there aren't that many different manufacturers, so not that many different systems.  I would say that each ship "handles" differently, and this is a major topic of the "Master/Pilot Conference" that happens when a pilot comes onboard.  For instance, our Captain tells the pilot that we have a variable pitch propeller, which most tankers don't have, so it tends to "back to starboard" (the stern drifts to starboard when going astern), and "dead slow" astern has almost no effect.  If your friend knows Capt. Nancy Wagner of the SF pilots, have him say hi, I was a senior when she was a freshman at Kings Point.

[chengkp75]

1 hour ago, anzore said:

He has told me some ships have old technology some newer. Some steer from the front, some aft some mid ship. He says there is no way to do them all.

Well, some ships do have their bridges forward, and some have their bridges midships or aft, but they all "steer" from the stern, where the rudders are.  It will affect the perception of steering, depending on where the bridge is, but all ships, due to simple physics, pivot around the same point.  Ships traveling ahead will turn around a point 1/3 of the way back from the bow, and ships going astern will turn around a point 1/3 of the way forward of the stern.  As for steering systems, there is really very little advance in technology over the last 4 decades I've been sailing.  Again, what I believe he means is that each ship steers a little differently, and this can be as simple as whether a tanker if fully loaded or in ballast, or whether a container ship's draft puts it very close to the bottom or not, or whether the wind is on the side of the ship.  Any helmsman working today will tell you that steering a ship is "art" not "science", and is something learned over years of experience.

 

And, while you are correct, as I've said before, that the pilot does not take the helm, if he didn't know how a ship will react to the orders he gives to the helmsman, then he would not know whether the order was correct or not.  I just believe you are misunderstanding what he is describing.

[jagsfan]

As a total layman (woman), I don’t know why I find all of this information fascinating, but I do. 

Thanks, you guys, for your time, effort, and impressive brain power!

[chengkp75]

4 hours ago, anzore said:

Cheng, you are the one misunderstanding me.. Per the Bar Pilot, who does this for a living, says that ships bridge and technology varies from ship to ship. There is no way a bar pilot can know how they all operate. He also said many ships have different systems for navigation due to the age of the vessel. This is per the pilot. I understand complete that the rudders and props are in the rear of the ship, which is stating the obvious. I also had coffee today with a long time merchant marine who said the same. 

Ah, now to say that the navigation equipment varies on different ships is totally different than saying that ships have different "ways of steering".  So, yes, it is reasonable to say that the pilot would not touch the controls of the navigation equipment, like the radars and ECDIS systems as the controls may differ, but that is a long way from " I have been told that each ship has a different way of steering , so there is no way a pilot can know all the different steering mechanisms." and "Some steer from the front, some aft some mid ship".

[Hlitner]

6 hours ago, anzore said:

Cheng, you are the one misunderstanding me.. Per the Bar Pilot, who does this for a living, says that ships bridge and technology varies from ship to ship. There is no way a bar pilot can know how they all operate. He also said many ships have different systems for navigation due to the age of the vessel. This is per the pilot. I understand complete that the rudders and props are in the rear of the ship, which is stating the obvious. I also had coffee today with a long time merchant marine who said the same. 

What you call "stating the obvious" is no longer the case.  Consider that the new Celebrity Edge has its Azipods (props) located near the bow.  And ships with Azipods generally do not have any rudder (I say generally since there is bound to be an exception to that rule).

 

Hank

[chengkp75]

Hank, not sure where you got that information, but the Edge's azipods are located conventionally at the stern.  It would be very difficult to design a hull where azipods were located at the bow, and that did not hang completely below the keel, which would make the ship extremely deep draft, and preclude entering most ports.

[Heidi13]

Agree with Cheng, the Edge Azipods are located at the stern on the drydock photos I saw. There might be confusion regarding the description that they are pulling, rather than pushing.

 

The only ships with propulsion up fwd that I am aware of is double ended ferries, where the loss in efficiency is made up by reduced docking time and fuel costs.Although Dynamic Positioning vessels will also have azipod drives up fwd.