It depends on the weather conditions like wind, season ,as in, the summers bring drought, monsoon where the rivers would be full and unsafe for travel .
It needs long travel…ling hours which causes sea sickness .
Water transport is limited to the areas where rivers are navigable and oceanic routes exist .
People who are travelling ships throw plastic, cans, biscuit wrapper etc. And fishes eat them by mistake and die. .
More chances of attack on boat sailing through .
Only can be used when sufficient water is available. .
In deep sea if boat gets in to storm, it becomes difficult to rescue. .
In waterfalls having much draft, water transportation does not works. .
Special maintenance for water tightness of boat is required. ( Full Answer )