New Locks vs Old Locks

[babs135]

What, if anything, is the difference between the locks?  Are they simply just bigger to allow passage for more ships and would someone who has passed through the old locks notice any difference?

 

Thanks.

Edited September 10, 2019 by babs135

[CruiserBruce]

Some reading would be beneficial. 

 

The locks are different to allow for BIGGER ships, not really more ships, (as in an increased number of ships transiting in a given period). The physical Canal is close to capacity in terms of number of ships it can handle,  so bigger ships allow for higher levels of cargo to transit, without adding ships. Frequently discussed here is the fact of relatively small numbers (less than a dozen) ships use the new locks every day. The two sets of locks operate somewhat differently, but still work on the principle of "lifting" ships up and over the Continental Divide using water.

 

The old system in generally considered one of the wonders of the world,  and part of that amazing feature, is that it still works very well today. The new locks are fine, but not sure they have the same amazement attached.

[BillB48]

Let add to what Bruce  said.  One of the biggest differences in the two locks is in the method the ships are taken through the lock.  The original locks use up to 8 locomotives ( electric mules) to take the ships through the locks, whereas the new locks use tugs.  The other difference that you would notice is the original locks is a twin flight, in other words two sets of locks side by side.  There is much more to see as you can watch your ship as well as a ship in the other set of locks.  The other "thing" about the new locks is the process to go through the three steps is a bit S-L-O-W-E-R.  That is not to say going through the original locks in an "E" ride at Disney (remember those?), but there is certainly more to attract your attention.

Edited September 10, 2019 by BillB48

[KeepCalmBearOn]

21 hours ago, CruiserBruce said:

The old system in generally considered one of the wonders of the world,  and part of that amazing feature, is that it still works very well today. The new locks are fine, but not sure they have the same amazement attached.

 

This ^^

 

The old locks are magical, astounding even.

[Heidi13]

On 9/10/2019 at 2:34 PM, BillB48 said:

One of the biggest differences in the two locks is in the method the ships are taken through the lock.  The original locks use up to 8 locomotives ( electric mules) to take the ships through the locks, whereas the new locks use tugs.  

Not sure of your definition of the "Mules" taking ships through the old locks. While they are secured Fwd & Aft on both sides, there role is only holding the ship in position.

 

When within the locks, ships use main propulsion to reach the far gate and also to move through a series of multiple locks. When dealing with "Panamax" size vessels, it takes a significant amount of power to drive the ship into the lock, as they must displace an equal volume of water. With minimal clearance on the sides and below the keel, the ship creates a pressure cushion ahead, so it takes significant power to push into the locks, way more than provided by the mules.

 

On my first trips through the Canal, I was amazed at how long we pushed into a lock, with engines stopped just before the end gate. Once engines were stopped the ship quickly stopped. 

[BillB48]

4 hours ago, Heidi13 said:

Not sure of your definition of the "Mules" taking ships through the old locks. While they are secured Fwd & Aft on both sides, there role is only holding the ship in position.

 

When within the locks, ships use main propulsion to reach the far gate and also to move through a series of multiple locks. When dealing with "Panamax" size vessels, it takes a significant amount of power to drive the ship into the lock, as they must displace an equal volume of water. With minimal clearance on the sides and below the keel, the ship creates a pressure cushion ahead, so it takes significant power to push into the locks, way more than provided by the mules.

 

On my first trips through the Canal, I was amazed at how long we pushed into a lock, with engines stopped just before the end gate. Once engines were stopped the ship quickly stopped. 

 

When I first operated the mules (tho we never called them that, but the public did) in 1969, the usual number of locos used per ship was 4... two on the bow and two on the stern.  Some of the larger vessels at that time use six locos, two on the bow, one each on port and starboard bow followed by two on the stern.  Very rarely were more than six used on any ship.  A four loco ship would not really be a challenge the width of the lock as their beam would rarely exceed 80', leaving ample room for water displacement as well as a lot of the six loco ships left ample room for water displacement.  Draft was not a factor.   On approaching the locks, normal procedure is to pick up the No. 1 center wall machine first, the pilot would use No. 1 cw to spring against or check movement towards the side wall along with his engine and rudder movements to position the stern.  After reaching the jaws of the lock where the No. 1 side wall loco came on board, both No.1 locos would be ordered to tow.  The stern was kept in check by the number 2 cw and engine/rudder movements.  After 2 side wall came aboard, both 2 locos maintained a breaking lead.  When the ship was far enough into the chamber No. 1 locos were brought back to a braking lead and both 1 and 2 locos were ordered to brake.  After the ship was stopped No. 1 locos were moved ahead to towing position to hold the ship during the fill/spill.

 

Moving between chambers...  After the gates opened, the normal command from the pilot was No. 2s release, No. 1s tow.  Depending on the ship and pilot the engine may (or may not) be used to overcome the initial inertia.  Keep in mind that bridge control of the engines at that time was a rarity... just the old telegraph.  Then you also had many more steam ships that often times by they had revs on the prop, the locos had the ship up to a standard towing speed which the fastest was 3 mph.  Some times diesels were a little more responsive, but still not all that rapid response.  Again when the ship was far enough into the next chamber, No. 1s were dropped back to a braking and then 1s and 2s ordered to break.

 

Ships requiring 6 locos would operate much in the same manner.  When a 6 loco ship was a Panamax, say 600+ feet and around 106' beam along with max draft (39 '06") more use of the ship's engine was the norm.  This of course was when the ship had to overcome the "piston" effect, a lot of water had to move down the sides and between the the keel and lock floor.  There can be as little as 2' of water between the keel and the lock floor.  The ship's engine will be used for the bulk of the time necessary to place the ship in the correct position in the chamber.  While getting the ship in the chamber it was normal procedure for the No. 1 locos to be towing and in some cases the No. 2 locos were in towing leads as well.  However more times than not, the No. 2  locos would remain abreast the chocks with tight wires which helped minimize slightly differences in towing force between the two No. 1 locos.  More than once I have had the No. 1 loco drawing over 500 amps during the towing portion of moving the ship.  Even had cases where a deep draft ship using a lot of engine, would stop engine because the stern had squatted too much and just wait for the water to equalize some to raise the stern.

 

OK, let's move into slightly more modern times.  As ships continued to push the limits of the original locks which are presently 965'x106', is when the method in moving ships in and around the started changing.  While there still were your classic 700 to 800 x106 max draft bulker ships, pure container ships and auto carriers were making their appearance.  At this time bridge control of fairly quick responding engines and were in the 700x106 ballpark, they were not particularly deep draft making it much easier to move.  There is a huge difference in the way a ship that size handles with 34 or 35' draft, there is so much more room under the keel to get rid of that displaced water.  This when the method of handling the ships  of this type started to change.  As the locos came on board it became easier to keep all machines abreast of the chocks and use the ship's engine to drive the ship into the chamber as well as move from chamber to chamber.

 

Panamax ships that are not particularly deep draft often times use a blend of towing and substantial use of the ships engine.  Also many of these Panamax ships are now using 8 locos, this in large part is due to fact because the height of the ship in comparison to the lock wall renders four of the locos useless at some portion of the lockage because of the almost vertical angle of the loco cable going to the ship.  Only when the ship is low in the chamber do all eight locos have effective angles/leads to work the ship.   On my last transit through the Canal in November, while moving from the upper level of Miraflores Locks, the control pilot had the No.1 and No. 3 locos in a towing lead and towing.  Really depends on the pilot, the ship, time constraints and even the response the pilot is getting from the loco operators as whether or not the locos are used more actively or not. 

 

I think that many cruise passengers have been treated to the version that the locos just center the ship in the chamber, it is an easy description to picture in the mind's eye.  While that is accurate to a degree, specially pertaining to Panamax passenger ships, it really is an over simplification of what is a fairly complex operation which has many different facets. 

 

A little historical look back... The first really modern pure mega container ship to transit was OCL's Tokyo Bay.  She was around 800' long and was 106' in beam.  She was just barely 2000 TEUs  Meanwhile 5000 TEUs or the norm at the original locks and the new locks just transited a 15,000+ TEU ship!

Edited September 12, 2019 by BillB48

[Essiesmom]

If you need a visual of the difference, here is a thread I started earlier last year, following ships through the canal.  Using the webcams of the canal, and bridge cams when ships have them (and they are working...).  Toward the bottom of the first page, you can see really good pics from the bridgecams of a Crystal ship.  On page 7, you can see pics from NCL Bliss in the new locks.  

 

This thread also has some cam views of the new locks:  

 

[ski ww]

Thanks for a very detailed explanation of how it's done. I really enjoy our transit of the canal & hope to do another.