Bucket

Used to retrieve from a tamed Cow.

Can also scoop up water, presumably to put out fires or make someone wet.

Can also be used to scoop water up and out of your boat if needed. As your ship will sink when its completely filled with water. The is used to rescue a sinking ship, by generating you and your crew more time to repair leaking planks etc.

Skill
To obtain the Recipe you need the skill "Shipwright".

See also Skills

Crop plot and farming
Some user tried to irrigate the crop plot using the water for Water Barrel but it doesn't seem to work.