The astrolabe was the primary navigational instrument used by Indian sailors. It was a circular brass plate with a graduated scale around the edge and a movable pointer called an alidade.

The astrolabe was used to measure the altitude of celestial bodies, such as the sun, moon, and stars. This information was then used to determine latitude and longitude.

The quadrant was used to measure the altitude of celestial bodies, such as the sun, moon, and stars. This information was then used to determine latitude.

The sextant was used to measure the altitude of celestial bodies, such as the sun, moon, and stars. This information was then used to determine latitude and longitude.

The compass was used to determine the direction of travel. It was a magnetic needle that pointed to the magnetic north pole.

The log was used to measure the speed of a ship. It was a rope with a knot tied at regular intervals. The rope was thrown overboard and the number of knots that passed through the sailor's hands in a certain amount of time was counted. This information was then used to calculate the speed of the ship.

The hourglass was used to calculate the time of day. It was a glass container with sand inside. The sand would flow from the top of the container to the bottom at a constant rate. The amount of sand that flowed through the container in a certain amount of time was used to calculate the time of day.

The backstaff was used to measure the altitude of celestial bodies, such as the sun, moon, and stars. This information was then used to determine latitude.

The kamal was used to measure the altitude of celestial bodies, such as the sun, moon, and stars. This information was then used to determine latitude.

The dhanu was used to measure the altitude of celestial bodies, such as the sun, moon, and stars. This information was then used to determine latitude.

The yasti was used to measure the altitude of celestial bodies, such as the sun, moon, and stars. This information was then used to determine latitude.

The pattika was used to measure the altitude of celestial bodies, such as the sun, moon, and stars. This information was then used to determine latitude.

The nalika was used to calculate the time of day. It was a water clock that consisted of a vessel with a hole in the bottom. The water would flow out of the hole at a constant rate. The amount of water that flowed out of the vessel in a certain amount of time was used to calculate the time of day.

The ghati was used to calculate the time of day. It was a sundial that consisted of a rod with a shadow. The shadow of the rod would move across the dial as the sun moved across the sky. The position of the shadow on the dial was used to calculate the time of day.

The palika was used to calculate the time of day. It was a clepsydra that consisted of a vessel with a hole in the bottom. The water would flow out of the hole at a constant rate. The amount of water that flowed out of the vessel in a certain amount of time was used to calculate the time of day.