Why should sailors be aware of water temperature?

Being aware of water temperature is crucial for sailors primarily to avoid capsizing and hypothermia. Water temperature can significantly affect a sailor's safety and comfort on the water. If the water is too cold, and a sailor falls overboard or capsizes, the risk of hypothermia increases dramatically, which can be life-threatening. Hypothermia can set in quickly in cold water, impairing a sailor's ability to swim or help themselves. Understanding the temperature of the water helps sailors prepare adequately, such as wearing appropriate thermal clothing or knowing the risks associated with cold water immersion.

The other choices relate to sailing strategy or logistics, rather than immediate personal safety. For example, while selecting the best sail for the conditions (the first choice) and determining the best time to sail (the last choice) are important considerations for effective sailing, they do not directly relate to personal safety in the same way that awareness of water temperature does. Carrying enough water (the third option) is significant for hydration but is not directly impacted by water temperature. Thus, the significance of water temperature in terms of safety makes the second choice the most pertinent.