Righting A Yacht That Has Gone Over!

[Zagato]

Very naive question but I am not used to yachts that are say 25 -30 feet. Is it it difficult to completely mess up and lose control of a boat this size dipping the mast in? If a yacht of this size is knocked flat will it just sink

Thanks Chris

 

[Little Rascal]

No personal experience but:

You'd have to be trying pretty hard to get the mast in the water - assuming you are in a normal yacht with a reasonable ballast ratio.

Most 'knockdowns' are either broaching when sailing downwind and overcanvassed, or being knocked down by a big breaking wave in gale/ocean situations.

The crucial figure for recovery is the AVG (Angle of Vanishing Stability) this is the angle of heel which a boat will not self-right from. For most boats the AVG is more than 90 degrees, ie with the mast underwater. Some will come up from 150 degrees or so. The AVG should be published somewhere, or it can be found on a stability/GZ curve chart for your boat.

Of course if you are knocked down with the hatches open you may well flood and sink. But with the hatches closed (they should be!) most boats should gradually recover.

The biggest danger is probably losing the rig in a knockdown rather than sinking.

 

[nimbusgb]

The short answer is no, a 30' monohull keelboat won't sink if knocked over on her beam ends. Chances are that most wouldn't sink if rolled right over unless the washboards are out and that's a bad idea in the kind of weather that might knock you flat in the first place. In most cruising boats you'd have to go to beyond 120 or 130 degrees before the keel starts working against you and tends to add to the complete rollover.

Once flat the boat will self right pretty sharpish. If rolled all the way over it could take longer and very beamy boats could well stay inverted until something else gets involved in the game.

Is it easy to do? It is if you know how but in reality you'll know when conditions are bad and will chicken out long beforehand. If only because your partner will be threatening grievious bodily harm unless you get the boat flatter! Most monohulls develop severe weather helm as the wind strength increases and keeping all the sail up is actually counter productive. Its more prone to happening when flying a spinnaker ond/or 'off the wind' so on a broad reach or closer to a run.

You'll see a roll start to happen, a little gust comes along and if the helm is a little slow or the gust a little too much the boat rounds up, take more direct strain on the sails and centrifugal force, resistance and wind effort get teh rail and boom end in the water. There's lots of shouting, swearing and red faces. the crashes from below are spectacular as the tea mugs and plates launch themselves across the saloon.

The boat then either stays pressed over, boom in the water can't spill wind or the spinnaker is full and drawing, or she stands up because she has rounded fully up to weather.

There's a pause of a second or two, the crew shake themselves off and release sheets, lower the bag and the recriminations start. The wife downstairs starts making nostradamus type predictions about whats going to happen once she gets off the boat and how this had better be in the next 5 minutes OR ELSE!

If its a racing crew they sheet in and discuss whether to change down to the #3 bag

Things tend to break when you 'broach' a boat badly. The loads on rig and sails are very high.

 

[Little Rascal]

...Most monohulls develop severe weather helm as the wind strength increases and keeping all the sail up is actually counter productive. Its more prone to happening when flying a spinnaker ond/or 'off the wind' so on a broad reach or closer to a run...

As you say theres no advantages to overpressing the boat (particularly if you're cruising).

Reef earlier, sail flatter and you won't go any slower.

Just watch it off the wind if you're really worried - put someone good on the helm once you start surfing.

And close those hatches if it's rough/gusty!

 

[Oceanmaster]

The short answer is no, a 30' monohull keelboat won't sink if knocked over on her beam ends. Chances are that most wouldn't sink if rolled right over unless the washboards are out and that's a bad idea in the kind of weather that might knock you flat in the first place. In most cruising boats you'd have to go to beyond 120 or 130 degrees before the keel starts working against you and tends to add to the complete rollover.

Once flat the boat will self right pretty sharpish. If rolled all the way over it could take longer and very beamy boats could well stay inverted until something else gets involved in the game.

Is it easy to do? It is if you know how but in reality you'll know when conditions are bad and will chicken out long beforehand. If only because your partner will be threatening grievious bodily harm unless you get the boat flatter! Most monohulls develop severe weather helm as the wind strength increases and keeping all the sail up is actually counter productive. Its more prone to happening when flying a spinnaker ond/or 'off the wind' so on a broad reach or closer to a run.

You'll see a roll start to happen, a little gust comes along and if the helm is a little slow or the gust a little too much the boat rounds up, take more direct strain on the sails and centrifugal force, resistance and wind effort get teh rail and boom end in the water. There's lots of shouting, swearing and red faces. the crashes from below are spectacular as the tea mugs and plates launch themselves across the saloon.

The boat then either stays pressed over, boom in the water can't spill wind or the spinnaker is full and drawing, or she stands up because she has rounded fully up to weather.

There's a pause of a second or two, the crew shake themselves off and release sheets, lower the bag and the recriminations start. The wife downstairs starts making nostradamus type predictions about whats going to happen once she gets off the boat and how this had better be in the next 5 minutes OR ELSE!

If its a racing crew they sheet in and discuss whether to change down to the #3 bag

Things tend to break when you 'broach' a boat badly. The loads on rig and sails are very high.

remind me not to try that out then.

 

[Searush]

They are not dinghies, as they heel, the stabilising force of the keel(s) increases & the force of the wind on the sails reduces as less area is presented to the wind (as it is now flat). When there have been knockdowns or 360's then it is usually a result of wave action rather than just gusts of wind. It is extremely rare for such events to happen to cruising sailors pottering around our coasts.

Read about the '79 Fastnet race if you want a better understanding of the sort of conditions that lead to knockdowns - and how many boats that were abandoned stayed afloat & useable throughout the storm. "Left for Dead" is an interesting account of someone injured in a knockdown & literally left for dead on an abandoned boat which stayed afloat & saved his life.

Broaching is usually a consequence of carelessness or carrying excessive sail for the conditions. Be cautious when sailing downwind in strong conditions, especially if the seas are confused. It doesn't always feel like you need to reef when running as your speed can knock an actual F6 down to an apparent F5 for example.

 

[Lakesailor]

Interesting page on heavy weather sailing and smashing a mast on the Sonata web site

 

[vyv_cox]

Some of the responses may not have completely put your mind at rest. There is little similarity between the adventures of racing yachts in the open ocean and a 25 - 30 foot boat used for coastal cruising. In well over 20 years of cruising in boats between 27 and 34 feet I doubt if I have ever heeled more than about 30 degrees. The big lump of iron underneath will always pull it back upright.

 

[ancientsailor]

No personal experience but:

You'd have to be trying pretty hard to get the mast in the water - assuming you are in a normal yacht with a reasonable ballast ratio ...

The crucial figure for recovery is the AVG (Angle of Vanishing Stability) this is the angle of heel which a boat will not self-right from. For most boats the AVG is more than 90 degrees, ie with the mast underwater. Some will come up from 150 degrees or so. The AVG should be published somewhere, or it can be found on a stability/GZ curve chart for your boat. ...
The biggest danger is probably losing the rig in a knockdown rather than sinking.

Agree with all that - and the other post which says it's usually a knock down by waves. There's a very well known video - here's one version http://www.youtube.com/watch?v=n_jz708oeVI about 40 seconds in the vessel is hit by a breaking wave ...

It's a work in progress (and possibly more detailed than you're looking for) but I am working on a explanation of stability. What I have done so far is available at the moment free here http://sailskills.co.uk/Stability/sailskills_stability_stability_explained.html

 

[Deleted member 36384]

In a leeward knockdown you will want to depower by dumping sheets. The main sail boom will be pushed to centre by water pressure on the boom so, the only way to depower is to release the kicker so that the boom lifts.

I have been pressed flat in a flat calm sea, sunny day on the Firth of Clyde. A crew member pointed upwind and remarked on the White horses. At that moment she was slammed hard on her side. It blew a 6 for the rest of the day. Dumping the kicker brought us upright enough to hand the genoa.

 

[Zagato]

Thanks - that is another concern over just another 88 to go! The biggest thing I have ever sailed is a twin keeled Westerly Pageant so your feedback is reassuring.....

Chris

 

[CAPTAIN FANTASTIC]

As the others said; it will be a miracle if you manage to turn a yacht upside down; I have been trying to tip my yachts over for some time now, but no luck

 

[Little Rascal]

In a leeward knockdown you will want to depower by dumping sheets. The main sail boom will be pushed to centre by water pressure on the boom so, the only way to depower is to release the kicker so that the boom lifts.

I have been pressed flat in a flat calm sea, sunny day on the Firth of Clyde. A crew member pointed upwind and remarked on the White horses. At that moment she was slammed hard on her side. It blew a 6 for the rest of the day. Dumping the kicker brought us upright enough to hand the genoa.

Cooo!

What boat was that in then?

 

[Kelpie]

A bit confused about how dumping the kicker helps. I would always have lots of kicker on to try to flatten the sail in stronger conditions, to reduce heel. Is releasing it a way of scandalising the main?

 

[ex-Gladys]

A bit confused about how dumping the kicker helps. I would always have lots of kicker on to try to flatten the sail in stronger conditions, to reduce heel. Is releasing it a way of scandalising the main?

Dumping the kicker makes the main twist off, so the sail spills off at the top.

I have been in a knock down.... whilst racing a Sonata over 30 years ago, we got a riding turn on the old jib sheet, that meant the jib was backed as we tacked in heavy weather. I was leaning on the (new) lee coaming and went up to my elbows in water, and looked up to see the spreaders in... Scary, but she screwed round and came back quicker than you could react.

PS the boat didn't sink, and didn't take any water internally

 

[Little Rascal]

A bit confused about how dumping the kicker helps. I would always have lots of kicker on to try to flatten the sail in stronger conditions, to reduce heel. Is releasing it a way of scandalising the main?

It's only a problem once the boom end has hit the water and you can't spill by easing the mainsheet.

Then freeing the kicker will lose you some drive and let you up.

 

[Resolution]

Knock downs are very unlikely to happen whilst cruising, but not unknown whilst racing. I used to race a Sigma 33 and we reckoned we weren't trying downwind under spinnaker unless we broached at least once a season. Given my lousy reactions on the helm it was often far more than once. Three times we managed to get it so wrong that the mast was well immersed. What was quite surprising was how high up out of the water the cockpit was even at 90 degrees plus. It never felt in any danger of taking water in the companionway, other than splashes. And as others have said, the lump of iron very quickly brings things back the right way up. The only danger is if a sail is pinning you down - so do be careful if using a preventer to hold the main out.

 

[sailorman]

Thanks - that is another concern over just another 88 to go! The biggest thing I have ever sailed is a twin keeled Westerly Pageant so your feedback is reassuring.....

Chris

Do they sail

 

[bobgarrett]

If its a racing crew they sheet in and discuss whether to change down to the #3 bag

Been there!

 

[Kelpie]

Dumping the kicker makes the main twist off, so the sail spills off at the top.

It's only a problem once the boom end has hit the water and you can't spill by easing the mainsheet.

Then freeing the kicker will lose you some drive and let you up.

Uhm, OK- should I be dumping the kicker only when at risk of dipping the boom? Or as a general means of de-powering?