Hot Stuff! Boating During the Dog Days

The ancients blamed the hot weather of July and August on Sirius, the intensely bright Dog Star. During these "dog days," an afternoon on the water can be especially refreshing, but hot weather can present boaters with challenges unique to the season. Watch the Weather. The number on the thermometer doesn't tell the whole story, so check the heat index before heading out. So-called popup thunderstorms are common on hot days, and while they don't usually last long, they can pack quite a punch. As always, if you see lightning, head for port. Performance.  Hot, humid summer weather reduces engine power and can knock your speed down by as much as 3 or 4 mph. It can't be helped, but it's nothing to worry about, either. If your boat is otherwise working properly, lower performance in hot weather is normal. Expansion. Heat causes vapor to expand, meaning that gas tanks that get hot can swell. Make sure your tank's vent, if present, is open and unobstructed, and be careful opening portable gas cans, as the pressure caused by expanding vapor can make gasoline splash out. Overheated? If your engine overheats, shut it down immediately. Letting an engine run while it's too hot can cause serious (and expensive) damage. Once the engine's off, you can start troubleshooting. Keep Your Cool, Too. The sun feels so good...until it doesn't. Protect yourself against sunburn with sunblock cream and relax under a shady bimini boat top. Just like you top up your engine's coolant before launch, keep yourself hydrated by drinking water, juice, or non-caffeinated soft drinks. Cold beer and cola are especially delicious on hot days, but alcohol and caffeine are diuretics, which can dry out your system. Switch up alcohol and caffeinated beverages with water to stave off dehydration. And please, boat sober: driving drunk is as dangerous and illegal on the water as it is on the highway. Know the Signs. Headaches and nausea are two signs of heat exhaustion. Muscle cramps, fatigue, confusion, and rapid heartbeat also signal that the body is overheating. Cool off in an air-conditioned cabin or other shady spot, and sip water or a sports drink. Lay some cool, wet cloths on your skin and rest. If you don't feel better after fifteen minutes, seek emergency medical attention; heat exhaustion can progress to heatstroke, which can be deadly. Resources:
Troubleshooting an Over-heating Engine
Preventing Overheating in Boat Engines
Heat Exhaustion