Which instrument is used to predict the approach of a low pressure system（）.

Preferred channel marks are aids to navigation which all following marks other than（）．

You are running parallel to the coast and estimate that the current is against you.In plotting a running fix using bearings from the same object on the coast，the greatest safety margin from inshore dangers will result if what speed is used to determine（）.

When steering a tow downstream around the shape of a sand bar，and staying on the proper side of the buoys，an operator should be cautious of（）.

You are entering an east coast port and see a buoy with a yellow triangle painted on it.This indicates（）.

Which nautical charts are intended for coastwise navigation outside of outlying reefs and shoals（）.

You are steaming in a westerly direction along the Gulf Coast.You see ahead of you a lighted buoy showing a red isophase light.Which action should you take（）.

When attempting an upstream landing while pushing empty barges ahead in a hard onshore wind，the approach is best made（）.

Which vessel would display a cone，apex downward（）.

You are making tow.A loaded，open-hopper barge with independent tanks has placards，with alternating red and white quadrants，located at each side and end.You inspect the barge and find slight traces of water in the wing voids due to condensation.What（）.