Isolated danger mark

An isolated danger mark is a special type of signpost used in the water to help boats know where it's safe to sail and where it's not.

Think of it like a warning signpost on a street, but for boats with colorful signs on tall poles stuck into the water.

Isolated danger marks are put in place to tell boats to stay away from potentially dangerous objects or areas such as rocks, shoals, or sunken vessels underwater. If boats get too close to these objects or areas, they might crash or get stuck, which could cause harm to the boats or people on board.

So, if a boat sees an isolated danger mark while sailing, it means they need to be very careful and avoid that area or object to stay safe.