Ideas_R_Bulletproof
FULL MEMBER
- Joined
- Sep 7, 2013
- Messages
- 810
- Reaction score
- 0
- Country
- Location
Handysize refers to a dry bulk carrier or an oil tanker with a capacity between 15,000 and 35,000 DWT. Sometimes they are used to refer vessels with dwt of up to 60,000, thus including Handymax and Supramax vessels under its category. These vessels also have shallower draught in comparison to larger Supramax, Panamax and Chinamax ships, which allows them to operate in most of ports and terminals across the world. Due to their small dimensions, handysize ships can serve ports and terminals of all sizes, even ports with length and draught restrictions. As they are fitted with on-deck cranes, they can also serve ports lacking transshipment infrastructure. As a result, handysize vessels make up the majority of bulk carriers over 10,000 DWT.
Handysize Nord Hakata
Today, most of handysize vessels operate within regional trade routes. These ships are capable of traveling to small ports with length and draught restrictions, as well as lacking the infrastructure for cargo loading and unloading. They are used to carry small bulk cargoes, often in parcel size where individual cargo holds may have a different commodity. Their dry bulk cargo includes iron ore, coal, cement, phosphate, finished steel products, wooden logs, fertilizer, and grains to name a few.
Handysize IVS Hunter
Handysize vessels are primarily built by shipyards in Japan, South Korea, China, Vietnam, India and the Philippines. In addition, some other countries also have the expertise and capacity to build small-sized bulk carriers. The most typical handysize ships being built today are of size 32,000 DWT with a draught of 10 m (33ft). They boast five cargo holds with four on-deck cranes for cargo handling. Some of handysize ships are also equipped with stanchions for easy loading of wooden logs on deck.
http://maritime-connector.com/wiki/handysize/
Well you are right about Karnaphuli draft being shallow but let me add that a lot of Shipbuilding is done in low lying places like the Netherlands and also some parts of Germany where terrain is similar to Chittagong and draft is no deeper than 30 feet, which is what Karnaphuli has where most of the shipyards in CTG are.
I
The draft is a few feet higher at high tide and that helps. Also floating an empty hull and then building the superstructure separately and adding it later in a high draft location can also help.
The Meyer Werft Shipyard in Papenburg, Germany is situated on the shores of the river Ems. In Bangladesh standards this river can be called a ditch or 'khaal' or 'nullah', and is a lot smaller than our Karnaphuli. The river Ems is barely 30 feet deep and has numerous treacherous sandbars.
HOW TO SQUEEZE A HUGE SHIP DOWN A TINY RIVER
Royal Caribbean's Quantum of the Seas squeezes past a sealock on the river Ems.
MEYER WERFT
IN EARLY NOVEMBER, Royal Caribbean’s latest cruise ship, the truly colossal Quantum of the Seas, makes its maiden voyage. It is a beast of a ship, 1,141 feet long with room for more than 4,000 passengers and amenities like a skydiving simulator. But before anyone can kill time driving the 30 bumper cars or snacking at the onboard food truck, the Quantum had to reach the ocean.
This proved to be quite tricky, because the shipyard the built the Quantum is 20 miles inland, along a river barely wider than the ship.
On Monday, a team at Meyer Werft, the German company that built Quantum, spent 12 hours inching the ship downriver from its shipyard in Papenburg to the North Sea. The river was juuuust deep enough for the vessel, and so narrow that the ship, which has a beam of 136 feet, had just a few feet to spare. It took six captains to get the ship to sea. To make it a bit easier, they made the trip backward, inching along at 3 to 5 mph, relying upon GPS and a floating crane that had to move a bridge out of the way.
“Everything is unusual on this trip,” says Bernard Meyer, managing partner of the firm.
The long journey down the Ems lasted through the night.
MEYER WERFT
Meyer is the great-great-great-grandson of Willm Rolf Meyer. He founded the company in 1795, choosing a spot in Papenburg so construction projects would be safe from storms. Passenger cruise ships comprise the majority of the projects these days, and the company's moved plenty of ships down the Ems in a process called “conveyance.” But the Quantum, which weighs 168,000 tons, is by far its largest.
Building the ship was a piece of cake compared to delivering it. The Quantum has a beam (its widest point at the water line) of 136 feet, just shy of the maximum size that can be conveyed downriver. At some points during the trip, the ship had just 2 feet of clearance on either side. Complicating matters, the Ems is dotted with sandbars and isn’t particularly deep. “It’s more like a ditch,” says Harri Kulovaara, an executive vice president at Royal Caribbean.
Preparing the River
The size of the river (or the ship, depending upon your point of view) was only part of the challenge. The Ems is crossed by three bridges, and each was swung open to allow Quantum to pass. The third, which is used by a railroad, didn't open quite far enough, so a portion of it was removed.
There was other prep work to do. The six captains who piloted Quantum over the twelve hour stretch spent two weeks practicing in a simulator. A crew dredged the river, deepening it to about 24 feet where necessary. The weather ultimately dictated when the crew could make its move; calm conditions were crucial, and a full moon (or no moon) is ideal to ensure the water was at its deepest. Although Meyer Werft can manipulate water levels using tidal barriers, it does so sparingly for ecological concerns. It did, however, close the barriers to keep the water level at high tide, at which time the Ems is roughly 30 feet deep. That's just enough for the Quantum, which has a draft of 28 feet.
Everything aligned on Monday, and the six captains set to work in the afternoon. Given the intense concentration needed to do the job, they worked in pairs for 90 minute shifts. One captain steered the bow, the other guided the stern. The unusual maneuvering system helps a ship this big precisely navigate tight turns and narrow squeezes, much like a tiller driver helps the driver of a hook-and-ladder firetruck navigate city streets.
Spectators lining the river could be forgiven for thinking Quantum was headed upriver, given that it went downriver backward. Using the propellers to pull from the front offers better control than pushing from the back (the same is true for front wheel-drive cars). Tug boats, attached directly, rather than by a cable, to the bow and stern of the ship, provided extra control.
The captains on Quantum watched computer simulations like this one to see the ship's exact position.
MEYER WERFT
In tight spots, the captains weren’t looking over the sides of the ship like a driver trying to fit into an SUV into a compact parking spot. They were watching conning displays showing information from the GPS that provided the ship’s exact position to within five centimeters, along with forecasts of where the ship would be in 30, 60, and 90 seconds if the steering inputs weren’t changed.
Now that Quantum is out in the open, Meyer Werft will make the final touches (the ship’s about 97 percent finished) before handing it off to Royal Caribbean next month. But Meyer’s relief won’t last too long: His shipyard already has the contracts to work on Quantum’s two sister ships, Anthem of the Seas and Ovation of the Seas.
Next spring, they’ll be dredging the river and opening the bridges for another harrowing journey to the sea.
The spectacle of watching Quantum going downriver drew a lot of spectators.
MEYER WERFT
https://www.wired.com/2014/09/conveyance-quantum-of-the-seas/
This shipyard in Papenburg is 20 miles inland from sea and routinely builds expensive cruise ships that displace in excess of 100,000 tons and have drafts that get close to the depth of the river. The following pictures show how they get these ships to the sea through this river. Building up to 30 ft. high draft ships is possible in Bangladesh, upto 40,000 DWT bulk carriers, we just have to plan things properly by collaborating in shipyard building with China and Korea.
"A crew dredged the river, deepening it to about 24 feet where necessary. The weather ultimately dictated when the crew could make its move; calm conditions were crucial, and a full moon (or no moon) is ideal to ensure the water was at its deepest. Although Meyer Werft can manipulate water levels using tidal barriers, it does so sparingly for ecological concerns. It did, however, close the barriers to keep the water level at high tide, at which time the Ems is roughly 30 feet deep. That's just enough for the Quantum, which has a draft of 28 feet."
we have to ask the question - how feasible is it do dredge our rivers down to 20ft or more, when it would require us to move millions of tons of sand just to dig down to 10ft depth... our rivers are unique in the world.... they carry more sand than anyone else can imagine...
