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Pakistan Navy - Ship Model Towing Tank
A Towing Tank, also known as a Ship Model Basin or a model towing basin, is the equivalent of a wind tunnel for ships. A long, top-opened tank of a rectangular cross section equipped with a towing carriage that runs on two rails on either side. The towing carriage can either tow the model or follow the self-propelled model and is equipped with computers and devices to register or control speed, propeller thrust and torque etc.
China Ship Scientific Research Center [CSSRC] designed such a facility for a Pakistani institute. At the Pakistan Navy Operational Commands Seminar 2019, Chief of the Naval staff Admiral Zafar Mahmood Abbasi on 30 December 2019 expressed deep satisfaction over performance of the newly established Naval Research and Development Institute (NRDI) and appreciated progress made by NRDI in various projects. He also praised the collaboration of NRDI with local industry and academia and said that such interactions provide opportunities to seek long term joint ventures/ collaboration in various emerging naval systems and technologies.
Pakistan's dependency on China is understandable as Pakistan doesn't have expertise and resources to build Frigates & subs of local design. But if these are designed in house it will give PN much more flexibility which can be used to build bigger ships in future. The Marine Design Center has been established and a ship model basin was under construction. So local designs may emerge soon.
Working on model scale, the Basin is able, in advance of construction of a vessel, and at relatively small cost, to furnish a ship designer with a prediction of the performance of a vessel, to within a few percent. It is frequently possible for the designer in turn to make changes in the plans of the vessel which will improve the ship performance, and for the Basin to confirm the effect of these changes by inexpensive changes in the model, all before actual construction of the vessel or machinery has begun.
The ship models are first towed without propellers, and are then run under their own power with propellers, in a long basin of water which is sufficiently wide and deep to represent open sea. They are towed or guided by a large carriage which runs on rails laid on the walls of the basin, much as a traveling crane runs ak)ng rails secured to the walls of a shop.
Ben Franklin was perhaps the first constructor of a model towing basin. Riding on a canal boat in Holland, he observed that the horses had to pull harder when the vessel passed over the shallow sill of the canal locks. Franklin thought the shallowness must have something to do with it. On his return to America, he built a wooden trough, made a model boat, fastened it to a string which he passed over a wheel with a weight on the end, and worked out calculations which confirmed his belief. He had discovered an important principle in hydrodynamics. For many years, ship models for towing test purposes were made of wax but under modern conditions soft pine wood proved a much more satisfactory material.
A ship model test towing tank is a kind of hydrodynamic force experimental facilities; Generally can be used to carry out fluid dynamic experimental studies such as ship resistance and performance, sea-keeping, seaway load, ocean engineering, underwater robot and dynamic positioning technology, is the important experimental equipment of Naval Architecture and Ocean Engineering hydrodynamics teaching and scientific research. Due to the existence of the side walls in a towing tank, the measured hydrodynamic forces would present some discrepancies compared to the open sea results. This phenomenon is referred to as the side wall effect.
SOURCE:
www.globalsecurity.org
A Towing Tank, also known as a Ship Model Basin or a model towing basin, is the equivalent of a wind tunnel for ships. A long, top-opened tank of a rectangular cross section equipped with a towing carriage that runs on two rails on either side. The towing carriage can either tow the model or follow the self-propelled model and is equipped with computers and devices to register or control speed, propeller thrust and torque etc.
China Ship Scientific Research Center [CSSRC] designed such a facility for a Pakistani institute. At the Pakistan Navy Operational Commands Seminar 2019, Chief of the Naval staff Admiral Zafar Mahmood Abbasi on 30 December 2019 expressed deep satisfaction over performance of the newly established Naval Research and Development Institute (NRDI) and appreciated progress made by NRDI in various projects. He also praised the collaboration of NRDI with local industry and academia and said that such interactions provide opportunities to seek long term joint ventures/ collaboration in various emerging naval systems and technologies.
Pakistan's dependency on China is understandable as Pakistan doesn't have expertise and resources to build Frigates & subs of local design. But if these are designed in house it will give PN much more flexibility which can be used to build bigger ships in future. The Marine Design Center has been established and a ship model basin was under construction. So local designs may emerge soon.
Working on model scale, the Basin is able, in advance of construction of a vessel, and at relatively small cost, to furnish a ship designer with a prediction of the performance of a vessel, to within a few percent. It is frequently possible for the designer in turn to make changes in the plans of the vessel which will improve the ship performance, and for the Basin to confirm the effect of these changes by inexpensive changes in the model, all before actual construction of the vessel or machinery has begun.
The ship models are first towed without propellers, and are then run under their own power with propellers, in a long basin of water which is sufficiently wide and deep to represent open sea. They are towed or guided by a large carriage which runs on rails laid on the walls of the basin, much as a traveling crane runs ak)ng rails secured to the walls of a shop.
Ben Franklin was perhaps the first constructor of a model towing basin. Riding on a canal boat in Holland, he observed that the horses had to pull harder when the vessel passed over the shallow sill of the canal locks. Franklin thought the shallowness must have something to do with it. On his return to America, he built a wooden trough, made a model boat, fastened it to a string which he passed over a wheel with a weight on the end, and worked out calculations which confirmed his belief. He had discovered an important principle in hydrodynamics. For many years, ship models for towing test purposes were made of wax but under modern conditions soft pine wood proved a much more satisfactory material.
A ship model test towing tank is a kind of hydrodynamic force experimental facilities; Generally can be used to carry out fluid dynamic experimental studies such as ship resistance and performance, sea-keeping, seaway load, ocean engineering, underwater robot and dynamic positioning technology, is the important experimental equipment of Naval Architecture and Ocean Engineering hydrodynamics teaching and scientific research. Due to the existence of the side walls in a towing tank, the measured hydrodynamic forces would present some discrepancies compared to the open sea results. This phenomenon is referred to as the side wall effect.
SOURCE:
