A tow of 9 barges is made up three abreast and three long. The towboat is faced up to the center string which is known as the（）.

A . To keep visitors away from the barge B . To prohibit smoking C . To prohibit open lights D . All of the above

A . A variable pitch propeller B . A variable pitch nut C . A fixed pitch parallel D . A fixed pitch screw

A . Protest acts of violence or misconduct by the vessel's crew B . State that damage to cargo or vessel was caused by improper loading or pilferage by others rather than ship's personnel C . State that the damage to ship，cargo or both was due to the perils of the sea D . State that the perishable cargo was damaged because of negligence by port authorities or other official

A . A bitt B . A bulkhead C . A V-spring D . A fishplate

A . Make periodic inspections of bilges B . Keep the barge under constant surveillance C . Have a properly certificated tankerman or at least one licensed officer on board the towing vessel D . Verify ullage reading

A . copper and antimony B . steel and babbitt C . aluminum or beryllium alloy D . zinc or an alloy of tin and lead

A . No fog signal B . A prolonged blast at intervals never to exceed more than two minutes C . A prolonged blast followed by two short blasts at intervals never to exceed more than two minutes D . A prolonged blast followed by three short blasts at intervals never to exceed more than one minute

A . chain B . wire C . nylon D . manila

A . towing vessel is less than 50 meters B . towing vessel is greater than 50 meters C . tow is less than 200 meters D . tow is greater than 200 meter

A . tow strain B . catenary length C . being in step D . Williamson's Tow

A . reduce the draft of the barge B . shorten one leg of the bridle C . place bulky deck loads as far aft as possible D . trim the barge down by the bow

A . independent B . lang lay C . preformed D . spring lay

A . Length of the towline B . Height of the towline connection C . Longitudinal position of the towline connection D . Direction of opposing force

A、when there are numerous corrections to be made or the corrections are extensive B、when a low-stock situation occurs and minor corrections are made C、every two years to update the magnetic variation information D、after every major hydrographic survey of the area covered by the chart

A . The reinspection will be made between the fourteenth and sixteenth months B . The inspector shall examine all accessible parts of the vessels's hull C . The inspector shall examine the vessel's machinery as well as equipment D . The scope of the reinspection shall be the same as for the inspection for certification，but in less detail

A . yaw B . surge C . sway D . swing

A . a vessel towing by pushing ahead B . a power-driven vessel，not towing C . a barge being pushed ahead D . either answer A or answer B

A . only a stern light B . a towing light above the stern light C . two towing lights in a vertical line D . two white lights in a vertical line

A . port and starboard strings B . outer strings C . drag strings D . side string

A . trim the tow by the bow B . trim the tow by the stern C . list the tow to windward D . adjust the length of the towing bridle

A . no fog signal B . one short blast C . one prolonged and three short blasts D . one prolonged，one short，and one prolonged blast

A . Refuse to accept the barge until all wing voids are dry B . Accept the barge and when weather conditions permit run with the wing voids open to ventilate the spaces C . Accept the barge and periodically check the wing voids D . Return the barge to the fleet and depart without the barge