I've had two recent encounters with heavy wind on my O'Day 25, which responded differently both times. Last night my wife, daughter and I were hit from the stern by an unseen 20 mph gust that laid us over more (much)than we wanted. We were on a starboard reach when the wind shifted, and a gust hit us from the stern (the wind went from 6 mph to 20 mph very quickly -- in the dark) I threw the main sheet, the boat weatherhelmed to starboard and heeled about 35 degrees as it rounded up while I was trying to uncleat the jib. I was confident -- sort of -- that we weren't going over, and sure enough we popped up as we came into the wind after a 180. About three weeks ago I was hit with a similar gust while on a port tack, close hauled. That time the wind came across the port bow. Instead of rounding up, the boat fell off and laid over significantly before I could free the jib. I think I understand why she rounded up last night, and didn't the first time; that is, the tack and the wind direction were the difference. Is that correct? Here are my other silly questions. What is it called when the boat falls off in a gust? Is that broaching? Second, for the benefit of my wife, er, the Admiral, what is the likelihood of a knockdown in those conditions -- fairly light wind of 6-8 mph followd by a 20 mph gust with no significant waves? From what I have read in the archives, the chances of going over are not great. Do the chances increase when the boat falls off? (it sure felt like it that day, but it happened so fast it's hard to recall how far over the boat was and how long it took to throw the jib sheet) BTW, last night, the best part was that the wind was directly aft. I have never gone so fast on a run. My daughter, the Rear Admiral, said she will continue sailing with me, "but to not let that happen again!" Aye, Aye! The REAL Admiral threatend to keelhaul me. But we returned to the slip without any damage that a few beers couldn't cure. Thanks Alan
silly questions about wind gusts
- Thread starter Alan Johnson8370
- Start date
- Status
I'm no expert
I have an O'Day 25 centerboard, and when I get out to "push things", I've never been able to get it to heel much more than 40 degrees. I read on my O'Day mail list of one owner who had the exact same model, got hit by a sudden storm level gust, went over 85 degrees, and popped back up. I think the design of the boat makes them very forgiving.
I have an O'Day 25 centerboard, and when I get out to "push things", I've never been able to get it to heel much more than 40 degrees. I read on my O'Day mail list of one owner who had the exact same model, got hit by a sudden storm level gust, went over 85 degrees, and popped back up. I think the design of the boat makes them very forgiving.
Thanks for the input
I should have specified that mine is also a centerboard model. I'll be sure to pass your experience on to the Admirals. I realized in reading the recent posts about rounding up that one thing I did wrong last night was to "help" push the boat into the wind. According to what I read, I should have backed off on the tiller to let it get control. I learn something new everytime I go out and read these mesages. Thanks again. Alan
I should have specified that mine is also a centerboard model. I'll be sure to pass your experience on to the Admirals. I realized in reading the recent posts about rounding up that one thing I did wrong last night was to "help" push the boat into the wind. According to what I read, I should have backed off on the tiller to let it get control. I learn something new everytime I go out and read these mesages. Thanks again. Alan
Downwind
Just a comment, I think sailing directly downwind at night is about the most dangerous point you can be on. A momentary wind shift, inattention to the course or difficulty seeing the wind indicator and you have a bad gybe and/or broach. In a strong wind, you might consider tacking downwind. Getting 'rounded up' when on a reach has dangers, but it happens. I'm more concerned with the instance when you were upwind, that it could suggest a lee helm. As long as your boat tends to turn upwind in most conditions, it sounds like normal stuff.
Just a comment, I think sailing directly downwind at night is about the most dangerous point you can be on. A momentary wind shift, inattention to the course or difficulty seeing the wind indicator and you have a bad gybe and/or broach. In a strong wind, you might consider tacking downwind. Getting 'rounded up' when on a reach has dangers, but it happens. I'm more concerned with the instance when you were upwind, that it could suggest a lee helm. As long as your boat tends to turn upwind in most conditions, it sounds like normal stuff.
Downwind
Good point John, and well taken. I considered those possibilites, and under the circumstances elected to stay on a downwind tack. I was about 1/3 mile from, and directly upwind of, the dock. There was not a lot of room to tack downwind, port or starboard, given my proximity to the shore and an island. There was no inattention at the time. After the round up I was wide awake and maintaining close attention to the wind and tack. Finally, it took less than five minutes to get into the shelter of the cove. All of that said, I appreciate your advice, and will store it away for future reference. Thanks again.
Good point John, and well taken. I considered those possibilites, and under the circumstances elected to stay on a downwind tack. I was about 1/3 mile from, and directly upwind of, the dock. There was not a lot of room to tack downwind, port or starboard, given my proximity to the shore and an island. There was no inattention at the time. After the round up I was wide awake and maintaining close attention to the wind and tack. Finally, it took less than five minutes to get into the shelter of the cove. All of that said, I appreciate your advice, and will store it away for future reference. Thanks again.
Angle of diminishing stability
May I suggest that you guys go to www.reading-college.ac.uk-marine- and find there the formula for calculating the angle of diminishing stability for your boat. I think anyone heeling to 40 degrees is crazy. Half the cruiser-sailers built today will capsize at less than 40 degrees. You should have the main cleated for instant release in a gust. Easing the tiller, instead of the mainsheet is asking for a knockdown -- and even if you avoid a knockdown the centrifugal force of the resulting turn could pitch your crew overboard.
May I suggest that you guys go to www.reading-college.ac.uk-marine- and find there the formula for calculating the angle of diminishing stability for your boat. I think anyone heeling to 40 degrees is crazy. Half the cruiser-sailers built today will capsize at less than 40 degrees. You should have the main cleated for instant release in a gust. Easing the tiller, instead of the mainsheet is asking for a knockdown -- and even if you avoid a knockdown the centrifugal force of the resulting turn could pitch your crew overboard.
A few things don't add up!
If you were sailing DDW (dead down wind) in 6kts then the jib was not drawing at all and the main would have been out on the spreaders. As the gust hits and starts to turn you to stbd, the main will start to luff and the jib begin to draw pulling the bow down. The only thing I can figure is that your main was in way too far for the run so when the gust hit the main became more powerful as the boat rounded. Dumping the jib sheet is the wrong thing to do because as the jib begins to draw it will counter the round up and push the bow away from the wind. John is absolutely right that sailing DDW at nite without a crew is begging for trouble. Much better to sail jibe angles of 140 apparent and short tack your way home.
If you were sailing DDW (dead down wind) in 6kts then the jib was not drawing at all and the main would have been out on the spreaders. As the gust hits and starts to turn you to stbd, the main will start to luff and the jib begin to draw pulling the bow down. The only thing I can figure is that your main was in way too far for the run so when the gust hit the main became more powerful as the boat rounded. Dumping the jib sheet is the wrong thing to do because as the jib begins to draw it will counter the round up and push the bow away from the wind. John is absolutely right that sailing DDW at nite without a crew is begging for trouble. Much better to sail jibe angles of 140 apparent and short tack your way home.
Samphire - Sailboat Capsizes, I disagree
Almost all the sailing yachts built over the last 50 or so years have an AVS (angle of vanishing stability) of between 160° and 125°. This is the point from which they do not recover when heeled. i.e. they capsize. As this is invariably beyond 90° the masthead will be in the water and it requires wave action to rotate the hull further. Wind alone cannot cause the inversion of a ballasted cruiser unless there is a downflooding problem (open hatches etc.) If she goes right over, B2 in Fastnet 1999 speak, it will require another significant wave to right her. Motorboats might have AVS values of less then 90° though. I tried the Reading Academy UK link (its only a few miles from my home) but couldn't get anything. Am very interested in the capsize formula though. Can you help please?
Almost all the sailing yachts built over the last 50 or so years have an AVS (angle of vanishing stability) of between 160° and 125°. This is the point from which they do not recover when heeled. i.e. they capsize. As this is invariably beyond 90° the masthead will be in the water and it requires wave action to rotate the hull further. Wind alone cannot cause the inversion of a ballasted cruiser unless there is a downflooding problem (open hatches etc.) If she goes right over, B2 in Fastnet 1999 speak, it will require another significant wave to right her. Motorboats might have AVS values of less then 90° though. I tried the Reading Academy UK link (its only a few miles from my home) but couldn't get anything. Am very interested in the capsize formula though. Can you help please?
Sampire - Response
Have to disagree with you Sampire on some aspects. I don't think heeling over 40 degrees is "crazy". For one thing, my boat isn't one "built today", it's a 1976 model. Plus, we're talking about VERY controlled situations. Our lake is large enough to sail, but still small enough that land is a short swim away. Additionally, I think it's important to push the envelope in controlled situations so you know your capabilities when things crop up on you.
Have to disagree with you Sampire on some aspects. I don't think heeling over 40 degrees is "crazy". For one thing, my boat isn't one "built today", it's a 1976 model. Plus, we're talking about VERY controlled situations. Our lake is large enough to sail, but still small enough that land is a short swim away. Additionally, I think it's important to push the envelope in controlled situations so you know your capabilities when things crop up on you.
- Status