A thrust block is designed to（）.

A sufficient amount of chain must be veered when anchoring a vessel to ensure（）.

A slow rise in the barometric pressure forecasts（）.

A tow can override its tug as a result of（）.

A spanner is a （）.

A towline should be fastened to（）.

A towing vessel’s fire detection system may be certified to comply with the Coast Guard’s towing vessel fire protection regulations by（）.

A swift current occurring in a narrow passage connecting two large bodies of water，which is produced by the continuously changing difference in height of tide at the two ends of the passage，is called a（）.

A tug is best positioned for towing and maneuvering on rivers and other restricted waters where wave action is limited when（）.

A time diagram is a diagram of the celestial sphere as observed from above the（）.