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Broach on a run?

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Voyager
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Initially Posted - 02/06/2008 : 23:36:29

I've been re-reading several sailing books this month, and read in the Glenan's Guide to Sail Trim if you should put your keelboat on a run, there is always the risk that the boat will turn uncontrollably in strong breezes and broach. Does not sound like fun.

I did not think that this would be a problem in the Catalina 25, but apparently it can be. Last summer when I was out on a run in 20kt breezes, I had absolutely no inkling that this could occur.

On the other hand, in my 16 foot centerboard daysailor, when on a run, the rig would oscillate the boat from port to starboard, from starboard to port, and if I didn't drop the centerboard or heel the boat intentionally by hiking out, the oscillations would increase until a capsize. If hiking out did not help, I'd have to head up, sail on a broad reach and tack down wind. This was a royal pain in the butt.

I read in Gary Jobson's Sailing Basics, that in a keelboat, if there's ever a danger of broaching, you need to do an S-gybe and sail on the lee for a short while, then luff, then gybe again to prevent this from happening.

Anybody have any experience with the C-25 broaching? Do you have any suggestions on what countermeasures would be useful to prevent it?

Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain � Milford, CT

Edited by - Voyager on 02/06/2008 23:38:36

Steve Milby
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Response Posted - 02/07/2008 : 07:30:34

Bruce, I haven't read that Jobson book, and can't figure out, from your description, what he's suggesting. Ordinarily, I wouldn't recommend that a sailor with average skills either gybe or sail by the lee in high winds, when there's a risk of broaching, because both are very difficult and risky maneuvers in strong winds, and if the maneuver doesn't go well, it could actually cause the boat to broach. To me, the better approach is to stay ahead of the problem. Take remedial action before it reaches the crisis stage.

Generally, a sailboat broach can be caused by the wind or by a wave, or both. A boat is in danger of broaching while sailing downwind when it is grossly overpowered, and the wind forces on the sails are not equally balanced on both sides of the boat. If the boat is broad reaching in strong winds with too much sail area up, and encounters a strong gust, all that overwhelming force is on one side of the boat, and the energy that is in the sails has to be released somehow. The lateral resistance that is produced by the keel won't allow the boat to slip sideways, so the boat rounds up violently to windward, the boat heels over to leeward, and the wind spills out of the sails, releasing the excess energy. The reason why the boat rounds up to windward is because a sailboat is designed so that the sailplan inherently produces more force aft of the center of lateral resistance than forward of it. That slight imbalance is what causes a well designed boat to have a slight weather helm.

If you're ever at the helm of a sailboat flying a spinnaker in strong winds, you'll very quickly learn that, when a gust hits, you should bear off directly downwind, to try to keep the wind balanced on both sides of the boat. If you allow it to get too far out of balance, the force will overwhelm the rudder's ability to control the direction of the boat, and the boat will round up violently to windward.

A broach can also be caused by a big wave when you're running downwind. When big waves are overtaking the boat from astern, they lift the transom first as they roll under the boat. The leading edge of the wave is very steep, so it lifts the boat quickly. As the wave moves forward and lifts the boat, the boat begins to surf down the face of the wave, just like a surfboard. When the boat gets to the bottom of the wave, it's going so fast that the bow, which has less buoyancy than the rest of the boat, buries the pointy end slightly in the water. This can cause the boat to trip over it's bow. The wave that brought the boat to this situation is now at it's steepest, and right at the transom. If the wave strikes the boat squarely at the transom, the boat is in danger of pitchpoling. If it strikes the boat more to one side than the other, the boat will likely broach, or in an extreme case, roll over completely.

The best way to avoid a wind induced broach is to reduce sail area. In doing so, you should reef the mainsail as deeply as possible, or set a storm trisail, if you have one, or even furl the mainsail completely, and also reduce the jib as much as possible. By doing so, you'll move the center of effort of the sails as far forward as possible, and that will reduce the tendency of the boat to round up to windward. The problem is that, when you do this, your boat speed will likely increase, and there comes a time when too much speed will create a danger of a wave induced broach.

The best way to avoid a wave induced broach is to reduce the boat's speed, by reducing sail area and, in an extreme case, by putting out a drogue.

Edited by - Steve Milby on 02/07/2008 11:17:54

Frank Hopper
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Pitcairn Island
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Response Posted - 02/07/2008 : 10:46:45

when a gust hits, you should bear off directly downwind

there it is

I think we C25 sailors are pretty lucky in that our boats have small mains and it is usually a combination of a gust and quartering wave action that spins us around. And when it happens all it really does is run a check on how you have things stowed below. We have great little boats.

Edited by - on

JimB517
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Response Posted - 02/07/2008 : 10:59:42

Rounding up while sailing downwind is really not fun. So is sailing into a broach. It can happen in our boats. Its why you want to inspect those pintles and gudgeons. In my expereince, this only happens in big winds, with a strong gust, and combined with a big wave on the stern quarter.

On days like that with winds around 20 and swells around 7 I just love to try to drop into the swell and surf it like I was a surfer. I'm not kidding it is real fun.

This works best on a reach. Just watch out for breaking seas, make sure you are dead down swell if it breaks. Don't fight the rudder, hold it real loose if this happens, you don't want to strain it too much. After the wave passes pull the boat back on course.

Too bad our boats really don't surf very well.

Edited by - on

Derek Crawford
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Response Posted - 02/07/2008 : 11:19:46

I had a wise old skipper tell me "if you get into trouble downwind, steer towards the "trouble". I.E. if running a chute or a poled out genoa, steer towards them. This should stop any death roll (rolling to port, starboard and back and forth).
BTW I think if you pole out a genoa in 20+ winds you have a death wish...

Edited by - on

stampeder
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Response Posted - 02/07/2008 : 13:38:04

Since this sounds like a theoretical situation - I'd say that a properly sailed C25 is not in danger of broaching.

If I was out in 20+ knots and had to be on a run, I'd probably drop my main and enjoy the ride at hull speed under headsail alone.

If I had my main up, I would not be sailing wing on wing in 20+ knots. If I were inclined to sail by the lee, I'd have a very secure preventer and most likely a reefed main.

When I was learning to sail my C25 I read Jobson's book and thought it was good.

Edited by - on

Dave Bristle
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Djibouti
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Response Posted - 02/07/2008 : 13:52:22

Hi Bruce... Running dead-downwind in 20 knots with the centerboard up?? I expect you'll have some trouble! The sailplan, as Steve describes, is designed to spin you out in that circumstance.

I suspect you know that in your neck of the woods you don't really get "swell"... When it's blowing 20 out of the east, you can get steep 5-footers, which look much bigger than that (especially during an ebb), but that's about what they are. Down-wind, they'll give you a good push, but I haven't felt like I was going to "spin out" in them. I think the fin keel is an advantage in that situation--it's longer for-to-aft than the swing and deeper than the wing. A light touch on the tiller is a good idea--your balanced rudder makes things feel easy, but it doesn't reduce the forces at the pintles.

You're probably more adventuresome than we were--more power to you! (Your standing rigging is only a few years old.) We liked to sail on the genny alone in those conditions--sorta like front-wheel drive with a very slight lee helm. We felt comfortable at just about any point of sail. It's a good tactic if you have squeemish passengers aboard on a blustery day. If you do that, just be sure to backwind the genny on a tack, to make sure it pushes you through, since the main isn't giving you that final push. I recall doing 4 knots broad reaching under a bare pole (and a sail cover) one day after we rolled up the genny--and even heeling a little!

Edited by - Dave Bristle on 02/07/2008 13:53:51

Steve Milby
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Response Posted - 02/07/2008 : 16:03:00

<blockquote id="quote">quote:<hr height="1" noshade id="quote">If I had my main up, I would not be sailing wing on wing in 20+ knots.<hr height="1" noshade id="quote"></blockquote id="quote">A couple of years ago I was crewing on an old 30' IOR masthead-rigged sloop in a very long downwind race. The wind was blowing 25 kts at the start, and we crossed the starting line wing and wing. The genoa was poled out, and we were doing between 8 1/2 and 9 kts. After about an hour, the wind subsided to about 22 kts, and our boatspeed dropped to 7 1/2 kts. At that time we raised a second genoa, which brought our speed back up to about 8 1/2 kts. One genoa was poled out to port, the other was to starboard and flying free, and the unreefed mainsail was wung out to starboard. We continued to run between 8 and 8 1/2 kts for long periods. That was the first time I had ever flown twin genoas, and was amazed at how stable the boat was in that much wind, but, when you think about it, by far, most of the sail area was forward of the CLR, and we never felt any motion in the boat that caused us to think that a broach was imminent. Before the night was over, we broke the owner's new whisker pole, but we won the race.

Edited by - on

Voyager
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Response Posted - 02/07/2008 : 16:03:08

This all sounds very exciting . . .
Last summer while I was out, I had the main reefed, and was playing the furler in and out on the jib.

Like I said, I was making good speed downwind, but didn't feel threatened in any way. Wind was out of the north and since there was no more than a mile or so of fetch, the waves were 1-2 foot, breaking occasionally. Not much to surf.

By the way, I misquoted the title of Jobson's book. <blockquote id="quote">quote:<hr height="1" noshade id="quote"> I read in Gary Jobson's Sailing Basics . . . <hr height="1" noshade id="quote"></blockquote id="quote">

The actual title is Sailing Fundamentals

I'm going to try to scan in the diagram on the S-gybe. He mentions it takes practice, don't try it your first time out and practice in lighter conditions. It's supposed to depower the sails.

In the 16 foot daysailor, however, I had a southeasterly fetch over 50 miles across LI Sound, so the waves were much bigger, and breaking. I was surfing quite a bit that day......

I kept the boat mostly upright that day.

Edited by - on

Steve Milby
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Response Posted - 02/09/2008 : 09:06:10

There's something else worth thinking about when it comes to sailing in high winds, because it helps keep things in perspective. 25 kts might sound like a lot of wind, but, when you think about it, when we were sailing downwind at about 8 kts boatspeed in 25 kt winds, that means the apparent wind was only about 17 kts., and you can still gybe safely and you still have good boat control in 17 kts of apparent wind, and you're sailing in sync with the waves. In fact, sailing downwind with the right amount of sail area for those conditions is beautiful, exhilarating sailing. On the other hand, if you turn around, and beat to windward at about 7 kts boatspeed in the same wind, the apparent wind will be about 32 kts., and sailing in those conditions will be a real struggle, unless you have just the right amount of sail area and good sail trim, and you'll be crashing bow-first into one wave after another. That's why running before the wind is such a popular storm sailing technique. If you get caught in high winds and have enough sea room to run before the wind, you should consider foregoing your intended destination to windward, and instead run downwind until you reach a river mouth or a cove or an island where you can anchor in its lee. Instead of scaring yourself and crew to death trying to beat to weather, you'll have a much more safe and pleasant sail. So what if you don't make it to your destination for another day or two? You'll get there when you get there. Call your boss and tell him you'll be late by a day or two.

Edited by - Steve Milby on 02/09/2008 09:43:48

Steve Milby
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Response Posted - 02/09/2008 : 17:11:44

Bruce, by pure dumb luck, I ran across a copy of Jobson's Sailing Fundamentals in a Half-Price Bookstore today, and found the page that describes the S-gybe. It's a little hard to describe, but it appears that, when you want to gybe in strong winds, you should sail a gradual "s" curve. When you reach the point in the curve where you are sailing by the lee, then you turn back the other direction in a slow curve, and, at about the same time, you gybe the mainsail. If you time both actions just right, it appears that it takes some of the force out of the gybe, so that the boom doesn't slam over nearly as hard. It looks like a maneuver that could be useful, if the skipper and crew are skilled enough to do it well, and if you have practiced it enough to be good at it, but it looks like it would be very difficult for a skipper to do shorthanded, or with crew that hadn't practiced the maneuver.

Nevertheless, it's well worth trying it out this summer. You never know, it might be easier than it looks. Thanks for pointing it out!

Edited by - on

Voyager
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Response Posted - 02/09/2008 : 20:01:08

Steve -
I can scan the diagram, and transcribe the description from the book (considered "fair use" among you copyright attorneys out there), but I haven't figured out how to insert pictures using "Forum Code".

Here's what Sailing Fundamentals says, by Gary Jobson:
<blockquote id="quote">quote:<hr height="1" noshade id="quote">. . . S-jibe, used when the wind is blowing hard and there is a chance of capsizing. In strong-wind jibing, the main boom comes over with such force that it goes too far out on the new side and the boat begins to round into the wind. At its worst, this loss of control can capsize dinghies or broach (spin out of control into the wind) larger keel boats. To stay upright, you must keep the boat under the mast and the boat in balance. Steering an S course when jibing can accomplish this.
As you go into an S-jibe, bear off and keep the boat sailing slightly by the lee. This is the point of sail where the wind is coming over the corner of the stern that the boom is still on. It is a temporary point of sail only. Keep the main overtrimmed at this time. Then, as the mainsail is coming across the boat, steer back in the direction in which the main is going. This change of course reduces the power in the sail and doesn't allow the boat to round in to the wind. As the sail fills on the new side, keep it overtrimmed and resume course, having completed your jibe. <hr height="1" noshade id="quote"></blockquote id="quote">

The picture shows the boat quartering on the port with boom to starboard, then on a dead run, then with wind coming over the starboard transom (on the lee) (this is the first half of the S), then turning back on a dead run, THEN doing a controlled jibe with the wind quartering on the starboard with the boom to port.

Ths is a pretty cool move, but who beside Gary J would you expect to recommend it?

Edited by - on

Dave Bristle
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Djibouti
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Response Posted - 02/09/2008 : 22:28:06

How 'bout that--that's exactly how I normally performed a jibe, and I never knew it had a name!

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stampeder
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Response Posted - 02/10/2008 : 22:04:24

seems to me that the S-jybe is one of those manueuvers that takes a lot of head scratchin' when you're on the couch. But on the water when you're in the groove and you are one with your boat, this is one of those things you could pull-off as a matter of course.

I took a course two summers ago with a national racing coach onboard Labarca - we did a lot of sailing by the lee manuevers.

Edited by - on

djn
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Response Posted - 02/10/2008 : 22:35:09

If you have a good amount of wind, you could just fly your jib, that will keep the pull forward and help keep the boat from brouching. Check this vid out.

http://www.youtube.com/watch?v=NKusg6Jyc9Y

Edited by - on

Dave Bristle
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Djibouti
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Response Posted - 02/11/2008 : 14:56:40

Interesting vid--shows the power of the sea (in medium-strong conditions). But I think that boat needs to get a drogue out to keep from swinging abeam of the seas.

Edited by - on

stampeder
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Response Posted - 02/11/2008 : 15:12:25

And Joshua Slocum would tell him he's got the wrong kind of boat for those seas, especially since he's got large following seas.
JS said he did not like the large sterm overhang because a following sea would always try to drive your nose down.

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John Russell
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Response Posted - 02/11/2008 : 15:44:51

Wasn't there some criticism of the solo circumnavigator that lost his boat last fall about sailing with only the headsail? I seem to recall that one of the criticisms he received from a few safe and warm arm chair skippers was that he should have had his mizzen up to steady the boat.

Edited by - on

Steve Milby
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Response Posted - 02/11/2008 : 17:09:55

If I remember correctly, John, it was just the reverse. The guy was only flying a sail from the mizzen mast, with no sails flying forward. He was sailing downwind in winds that he estimated at about 50 kts. The wind caused the transom to slue around beam-to, and the boat suffered a knockdown. You can't say with certainty, but I'd bet he wouldn't have been knocked down if he hadn't been flying such a completely unbalanced sailplan. A woman with a much smaller boat survived the same storm with no such problems.

I agree with Dave that the guy in the video should have had a drogue out, or alternatively, he might have still been able to heave-to. In the short video, it didn't look like the waves were breaking yet, but he was definitely having trouble steering. At the end of the video, he was beam-to the waves, but fortunately for him, the next wave wasn't very big.

Boats with a long overhang might not be the ideal design, but those old classics have survived a lot of major storms through the years.

Edited by - on

djn
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Response Posted - 02/11/2008 : 17:19:49

Hi Steve, my boat has the same shape as the one in the vid, but mine is a fractional sloop rig. It raced the Fastnet race five time back in the fifties and was the design of the day for that period. Cheers.

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Steve Milby
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Response Posted - 02/11/2008 : 17:41:48

Dennis, I sailed with a friend on his Hinkley last summer. It was about a late 1970's - early 1980s vintage boat, and it was really a sweet ride. You're lucky to have such a beautiful old classic.

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Dave Bristle
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Djibouti
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Response Posted - 02/11/2008 : 17:58:39

I recall what Steve recalls--that the guy was flying a mizzen sail only in following seas and wind--it looked absolutely crazy, regardless of whether I was safe and warm.

I also wish I could remember what I read very recently about how a stern overhang is an advantage in following seas because it keeps the waves from pushing on the transom to spin you out for a possible broach. (It may have been in a recent Soundings or Sail.) The same can be said for a full keel, which gives more directional stability--especially in following seas. But even with both, a drogue can be very important in big seas. I think that weaving boat in the video illustrates the reason pretty well.

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Champipple
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Response Posted - 02/11/2008 : 18:07:04

So the one thing that is mentioned that I haven't seen is on page 45 of the jobson book. Over trim the main... So when you are sailing by the lee you start to trim the sail in so as to minimize the amount of travel it has, then on the backside of the S turn you start to ease out.

If pleasure cruising with non sailors I will tack and go all the way around the block just to keep things safe.

Edited by - on

JohnP
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Response Posted - 02/11/2008 : 19:18:25

Sailing in October downwind off of my marina in a gale, my passenger and I had a sweet ride about 5 miles down the Magothy River toward the Bay, to our weekend anchorage behind an island, at about 6 knots with only a storm jib. I was pleasantly surprised.

Our boats have nice options for most conditions, 12 foot swells and 40 knot winds excepted.

Edited by - on

Steve Milby
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Response Posted - 02/12/2008 : 08:18:09

In conditions like what you see in the video, the steering often becomes very sluggish. You put the helm over, and nothing happens - the boat doesn't respond to the rudder. I'm not sure exactly what's happening, but I think that, after the boat runs down the face of a wave and reaches the bottom of the wave, the bow plows into the water at the bottom of the wave, the boat slows almost to a stop, and the rudder stalls, and momentarily, the rudder becomes completely ineffective to control the direction of the boat. The rudder continues to be ineffective until the boat regains enough speed to have steerageway. The problem is that, when the boat is in the trough, the sails are sheltered from the wind, so they aren't much help in getting the boat underway again. With an ineffective rudder and ineffective sails, it's no wonder you lose steerageway in a deep trough.

When you notice that starting to happen, I think it's time to change your storm sailing tactics. If you can't prevent the boat from turning it's beam to the waves, you have to do something different. You could heave-to, which slows the boat so that it doesn't race down the face of waves anymore, and thus, it doesn't lose steerageway when it reaches the bottom of a wave. Heaving-to also creates a slick that tends to calm the waves. Or, you could stream a drogue, which would slow your speed and keep the transom oriented to the waves, or, you could ride to a parachute sea anchor, which keeps the bow oriented to the waves and practically stops the boat. The manufacturers of drogues say there comes a time when it becomes dangerous to continue using a drogue, so the ultimate heavy weather device seems to be the parachute sea anchor, which presents the pointy end of the boat at the waves, which is the strongest point, and best designed to shed water.

Edited by - on

Dave Bristle
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Djibouti
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Response Posted - 02/12/2008 : 11:01:27

I have suspected that as the front of a big wave moves under the boat (when you're running down-sea), the water is momentarily moving with the boat, which means the rudder has little or no effect. If the water is running faster than the boat, the rudder will act as if the boat is motoring in reverse--the opposite of what you expect--yawing the boat in the opposite direction to what you think you're steering. Then after the crest passes you, the water motion reverses and the effect of your rudder reverses. Very confusing to the helmsman.

That's my theory anyway...

Edited by - Dave Bristle on 02/12/2008 11:02:07

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