Panama Canal recommended system: Slave tank locks

Panama Canal Recommended System: Slave-Tank Locks

Attached is a shorter presentation on Bert Shelton’s recommended integrated system, given to the Panama Canal Authority (ACP).  It contains illustrations of how the slave-tank locks operate — using the same components as the existing locks and the planned side-tank locks — to yield far greater water savings and transit capacity, with far less environmental impact.

Today’s Panama Canal incorporated and improved upon the water-saving techniques of the side-tank locks, which were an advance of the previous century.  The slave-tank locks build on both and represent an improvement on the advances contained in the Panama Canal today.

The 3rd generation slave-tank lock’s efficiencies save more water more effectively (with fewer parts).  As an example, to achieve water use reduction of a comparable level, the side tank locks would require a fourth re-cycling tank per chamber.

This is only one level of the picture, however.  In addition to the recommended locks using less water individually, Mr. Shelton arranges the system to capitalize on all available water-saving techniques, achieving even greater overall system-wide reductions.

Integrating the variables optimally is the key to this system’s effectiveness in maximizing the use of the available water resources.  (With the current expansion project being managed in separate parts, i.e.broken up, these potential synergies disappear — along with the possiblility of future expansion without needing more water — leaving it unable to benefit from them.)

Feedback from experts in various fields has helped this development process succeed and continues to be very important.  Copied below is some additional information about the alternative system.



A new water-saving lock variant has the potential of being very beneficial to the Panama Canal Expansion project.

This new lock design, known as the ‘Slave-Tank Locks’, would significantly increase the capacity of the Panama Canal beyond current plans, with the same water, provide two larger lanes (instead of one), allow for future expansion and greatly reduce, if not virtually eliminate key environmental concerns, when integrated into the system.This information on advances in canal technology has been provided to the Panama Canal Authority (ACP).  It is still not too late to make the necessary modifications to incorporate them in the project, which would ensure the long-term future of the Panama Canal. Slave-Tank Locks are comprised of traditional components – chambers, gates, tanks,piping, and valves – and they operate using gravity flow, as istraditional.  Having two lanes as a key element of their design, these new locks are arranged, and their components interconnected, such that the componentsare used more effectively than with other designs.  The new lock arrangement not only uses less water per transit, it does so having relatively fewer components and with fewer water moves as compared, for example, to side-tank locks.  With the new lock, a twin-lane Alternative System for the Panama CanalExpansion has been developed that can be operated with the water thatis presently slated to operate one lane.  This alternative can yield 67% more daily transits than the 12 the planned system reportedly yields. The three known water-saving methods – steps, «recycling», andtransit-by-transit lane reversal – are combined in the AlternativeSystem to minimize the use of water.   Having two lanes is of benefit, because, should an unavoidable or an unplannedlane shutdown occur, the most critical large-ship transits could stillget through. Attached is a Power-Point file containing a series of slides extracted from alecture on lock systems for reference to allow visualizing thealternative system and new lock design.

Description of the Alternative System The Alternative System has two steps at each end of the canal.  Its layout includes Miraflores Lake and a new small «lake» – more of a short channel segment – at the Gatun end. The primary function of those «lakes» in this system is to permit the locks to be reversed transit-by-transit, which cuts the per-transit water-useeffectively in half.  A secondary benefit of the presence of those «lakes» – between Gatun Lakeand each respective ocean – is the buffer they provide against theintrusion of saltwater.  They not only disrupt the process that normally brings up the highest concentrations of salt, they serveas the place in which to perform practical saltwater mitigation procedures.   Miraflores Lake, whether it was intended by design to or not, today performs that function. The Base Case Design of the Alternative System would have a total of 8 main chambers, and a total of 16 main gates.  It would have only six (6) recycling tanks. Three of the two-lane single-step lock units of the Alternative System would be of Slave-Tank design.  Thefourth lock unit – the one next to the present locks of Pedro Miguel -would not have recycling tanks; the unit would look like a largerversion of the locks presently there. The Slave-Tank lock units of the Base Case Design each would have two (2) recycling tanks.  Itis possible to add two (2) more tanks to each of these, in a «secondfloor» arrangement, and further reduce water-use, by nearly 25% for the system.  In other words, the system has additionalwater-saving capabilities that could be added now or in the future, aswater-use needs change.

Operating Water

The Alternative System’s development also considered where to obtain operating water. It is recommended that operation of the existing «older» locks be modified when the new locks come on line.  They should be operated in their «50%» water-saving mode, at least part of the day.  That per-transit water-savings can be obtained whether ships all transit inone direction or the lanes are transited in opposite directions.  The procedure requires tighter scheduling of ships.  Theoptional water-saving mode is slower, which means fewer ships willtransit those locks in a day, but the benefits to using that operatingmode are significant. By using that mode fully, or partially, the need to change Gatun Lake’s fluctuation range goes away, which means:

  • modifications to facilities and structures all around the lake go away.

trusted lake management procedures need not be altered.

having to lighten present lock transit loads due to low water will happen less often    Also, four (4) feet of dredging into rock the length and width of the Cutwill go away; that work can be re-directed to making wider ship-passingareas along the canal route. To illustrate the power of shifting water-use from the present locks tothe proposed Alternative System, consider reducing transits of theexisting locks by one third.

  • 24 to 26 transits a day of the present locks would result.

The time normally used to transit another 12 to 13 ships would be left over.

The leftover time would be distributed among the transits to save water.

The 24 to 26 transits would use only 12 to 13 normal transits-worth of water.

24 to 26 normal transits-worth of water would be left available for the new locks.

The Base Case Alternative System needs only 11 present lock transits-worth of water.

A SECOND Base Case Alternative System can be operated, with the water left over.

Having water left over means that the chambers can be enlarged some, which has its own benefits and future potential.

Notes on Cargo Capacity

Publicized information about the planned Panama Canal Expansion seems to indicatethat the planned system, comprised of the new and the «older» locks, isto transit a combined 42 ships.  12 transits will presumably be of Post-Panamax ships carrying up to triple the cargo of a Panamax.  That leaves 30 transits of Panamax size or smaller ships through the «older» locks.  Max cargo capacity for the system would then be equivalent to about 66 Panamax transits. It is estimated that the Base Case Alternative System’s max cargo capacity- combined new and old lock transits – would be equivalent to about 94Panamax transits. If the capabilities of the water the «older» locks presently use were maxed out per the approach described above, the canal’s max cargo capacity would be equivalent to about 144 Panamax transits.  Only after that does enlarging the watershed have to be contemplated. In effect, this alternative resets the target for the consortia to meet orexceed in their proposals, in relation to cargo capacity that their designs extract from the canal water resources.  Any design that ties up resources less effectively permanently lessens the future benefits the canal can extract from its water resources.

Closing Comment The objective of this effort was to develop the most effective lock system possible (as was the case with the mechanical system (SSL) presented previously to the ACP).  It has been carried out to ensure nostone has been left unturned in Panama’s effort to present to the worldthe finest canal expansion possible – a canal that will be held in thehighest regard for generations to come.

2 respuestas

  1. Another attempt of the US to control the Panama Canal

  2. Not at all. Para nada.

    Estas recomendaciones son los resultados de estudios independientes y beneficiarian tanto a Panama y a su poblacion como a los clientes del Canal y a consumidores alrededor del mundo. Visite

    These recommendations are the result of independent studies and would benefit of not only Panama and its population but clients of the Panama Canal and consumers around the world as well. Visit

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