cathead

In nautical|lang=en terms the difference between mainmast and cathead

is that mainmast is (nautical) the chief, and tallest mast of a sailing ship that has more than one mast while cathead is (nautical) a heavy piece of timber projecting from each side of the bow of a ship for holding anchors which were fitted with a stock in position for letting go or for securing after weighing.

As nouns the difference between mainmast and cathead

is that mainmast is (nautical) the chief, and tallest mast of a sailing ship that has more than one mast while cathead is (nautical) a heavy piece of timber projecting from each side of the bow of a ship for holding anchors which were fitted with a stock in position for letting go or for securing after weighing.

As an adjective navigational

is pertaining to navigation.

As a noun cathead is

(nautical) a heavy piece of timber projecting from each side of the bow of a ship for holding anchors which were fitted with a stock in position for letting go or for securing after weighing.

In nautical terms the difference between cathead and catfall

is that cathead is a heavy piece of timber projecting from each side of the bow of a ship for holding anchors which were fitted with a stock in position for letting go or for securing after weighing while catfall is a rope used in hoisting the anchor to the cathead.