Tuesday, March 8, 2011

Panama Canal Transit: How it Works

The Panama Canal was built by the American Government (not the Army Corps of Engineers) in the years 1903 through 1914. After much debate about the merits of a sea level canal versus a lock canal, it was decided by a close vote in the US Senate to build the canal with locks.

Besides the ditch itself, there are seven major constructions: four dams and three sets of locks. The dams create lakes that supply the water and electricity for the canal. The central lake Gatun is about eighty feet higher than sea level. There are six pairs of locks: three (one at Miraflores, two at Pedro Miguel) on the Pacific Ocean side and three (at Gatun) on the Caribbean Sea side.  The locks do the heavy lifting using water from the lake and the lake surface itself is the canal for more than one half of the length of the canal.

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The operation is simplicity itself. The boat passes at sea level into the first lock through a set of open gates. Once the vessel(s) is secured to the side walls, the gate closes behind and about twenty five feet of water are allowed into the lock. Once the boat has risen with the water, a gate ahead opens and the vessel motors (or in the case of  large ships is towed) ahead into the next lock. Once three locks have lifted the vessel to the level of Gatun Lake, it motors for about thirty two miles to the set of three locks that will lower it back to sea level. In these locks the water is drained out into the lower level lock or finally the ocean.

The locks are built in pairs so the canal can support two way traffic at once. A very simple system is used to indicate to vessels which of the pair to enter or to wait. There is a semaphore, a large arrow that points to the left channel, the right channel, or straight down meaning wait.

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As we approached, we saw a ship ahead about twenty five feet above our level in the next lock. We also saw the USS Florikan, its tugs, a lone tug, and the sport fisher that would accompany us for our entire transit.

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We side tied to the sport fisher for each lift of lower in a lock and untied so we could all motor ahead separately.

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A we entered we passed gates folded back into the sides of the canal. Remember these gates are nearly one hundred years old.

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Once Panama took over the canal they made some upgrades including replacing the old bull gear and connecting rod mechanism for opening and closing the gates with a modern hydraulic piston.

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As we entered the first lock we were behind the USS Florikan and its tug. We were side tied to a sport fisher that was tied to a tug that was tied to the side wall. The good news for us was that we didn’t even need to tie to the starboard wall at all. The motive power for the Florikan was mostly provided by the “mules” shown on the both walls. These small locomotives keep the vessel off the side walls as well as pulling it through.Virago Rescue Paul 121

Virago Rescue Paul 122  How big a ship can the canal accommodate? There is a measure called Panamax meaning that a ship must fit into the 1,000 foot long 110 foot wide locks. How big is that? Here we see one passing us going the other way.

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After we were lifted we moved forward and the gates formally ahead of us now closed behind us and workers can cross using the gates as a bridge.

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There are always spectators, but I didn’t see any score cards.

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Once through the Miraflores and Pedro Miguel locks we motored out onto Gatun Lake for thirty two miles of smooth motoring. We passed under the Centennial Bridge and through Galliard Cut made famous as the bane of the French canal effort due to its frequent landslides.

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The former Calebra (Snake) hill now looks like a solid stepped pyramid.

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Panama is in the tropics and lake shore is heavily vegetated and dotted with small light houses and range markers.

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One rubber necking hazard on the canal is the giant crane named Titan. It was a war reparation from Germany after World War II and spent many years at the port of Long Beach. It is currently used to remove gates for repair. It certainly is overly photogenic.

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We crossed Gatun Lake at the requested eight knots, but had to wait about an hour for the “dead tow” USS Florikan to catch up. As we went down through the Gatun locks we were up front with the USS Florikan behind us. Here you see the double gates installed to conserve the Gatun Lake water in case a run away ship should deform one of the gates.

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Free at last! Free at last! We see loading cranes at Colon harbor at Caribbean sea level.

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For more about the canal and its history follow this link Panama Canal.

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