I'll admit it- I've been caught by squalls. In daylight too.
These oops fall into two categories: (1) I underestimated the squall I could see coming and (2) pop-up storms that come out of nowhere fast; in our area a storm can brew from nothing to 40,000' in five minutes.
Now, I am conservative and no longer tempt fate; when a squall is coming I prepare as if it's going to beat us hard. Or, sort of hard, we do usually keep some sail up. That said, there have been a couple occasions when in preparation I dropped the main, covered the main, and lashed 3/8" line around and around the covered main/ boom (I learned that the hard way too.)
No one had ski goggles, but we did have a dive mask
Prep is not all about sails.
Driving rain at 60+ knots is impossible to see through, and it hurts like heck. As well, a squall usually drops the temperature significantly AND add the wind and being wet, one can get cold mighty quick.
Thus I have learned THE HARD WAY to not only prep the sails. By the time the squall hits I have everyone below. At the same time, either on hand or ready to pass up: clear Oakley "sunglasses" and/or dive mask, foul weather jacket (I'm OK with frozen legs), folding blade attached to ME, knit cap, and gloves, life jacket, and harness.
Because when the squall hits, you're not going to be doing much of prep; it's too late to try to get the main down, it's too late to dig out the foulies.
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Now, everyone has focused on squalls while under way. What about at anchor?
Probably THE worst squall I've been through was up in St. Lawrence at a popular anchorage. We had PLENTY of warning- HOURS. Weather tracked it for 400km and gave regular reports of what was getting torn up and how badly. An hour before it hit, right around sundown, we could finally see it, and the lightning for the next hour, marching toward us, was incredible. When it hit all boats went over at least 45 degrees. Then it was total mayhem.
Some people closed hatches. Some sat and watched the storm. Some continued drinking right up until clobbering time. I had a spare anchor on deck, the motor running, and I was fully suited when it hit- just like if I were at sea. We survived the initial hit, so it seemed we'd be OK. Being fully suited for the severe weather, I jumped into the dingy and started pulling sailboats off rocks, no easy feat in 60 knot winds, 2' seas, and blitzkrieg lightning. Most of the sailors in the anchorage though were unprepared in just about every way possible. Prep is what made the difference.
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Now a light hearted squall tale.
It was an absolutely glorious friday evening, with two hours before sunset. We stayed at the dock and invited boating friends for a BBQ at the picnic table on the pier.
It was shaping up to be one of those wonderful meals. Chicken coming off the grill, umbrella up, table set with paper plates and condiments and silverware.
"Huh? What the heck is THAT?" I looked up and to the west. A solid black line over the trees- uh oh. Meaning, it was a mile away.
We had time to do nothing before it hit. Everything went flying. What we did grab was ripped out of our hands. Most of the meal and all the stuff ending up on the ground and flying off.
I'm sure this was on radar. But I didn't look at radar. I don't think I'd even turned on the VHF. It was a perfect evening, surely it would stay that way; it never occurred to me that there could possibly be any weather coming. I got learned.