What would happen if it became foggy or dark on a boat?

If it became foggy or dark on a boat, visibility would significantly decrease, making navigation more challenging and increasing the risk of collisions with other vessels or obstacles. The crew would need to rely on navigation instruments and lights to ensure safety. Additionally, using foghorns and sound signals would be essential to alert nearby boats of their presence. It would also be crucial to slow down and maintain a vigilant watch to avoid accidents.