Talk:Broach (nautical)

Rudder angle

Would you want to mention that the primary hydrodynamic hull force that is overcome is also know colloquially as 'the rudder'? Maybe work-in that, as the angle of heel increases, the rudder becomes increasingly less effective at counteracting weather helm, leading to an increased risk of broaching.

Also as the helm winds-on more rudder angle, to compensate for reduced rudder authority, there is a danger, especially on modern race boats with high aspect ratio rudders, that the water flow over it will separate, leading to a rudder stall in which case a broach is a very likely outcome as the helm no longer has control of the boat.

- HighlyErratic 21:36, 15 February 2009 (UTC)

Umm... how does accidental gybes relate to Broachin. Not in any way if you ask me! Please remove.

- Heikki 21:48, 27 September 2009 a.d.

Broaching vs rounding up

Just a question, since I don't usually sail "in English": What is the difference between broaching and rounding up? Thanks. 84.167.13.134 (talk) 09:02, 28 January 2011 (UTC)

Broaching starts with the wind behind and ends with the wind on the beam; rounding up starts with the wind on or ahead of the beam and ends with the boat nearly head-to-wind. I'd say. I thought you could broach to leeward too, where the wind ends up on the beam opposite to where it started, particularly with poled out headsails or spinnaker, and preventered main, but the article doesn't seem to mention that. Maybe these are two topics the article could be improved by mentioning --Nigelj (talk) 21:13, 28 January 2011 (UTC)

Broaching as a tactic

In offshore races in the UK (and I am sure elsewhere) broaching occurs quite frequently. As long as the crew are warned and able to hold on to something, and either only a windward broach is allowed to happen, or the boom is secured by a 'preventer' there is little risk, and pushing a boat's downwind performance by keeping more sail up than could be sustained upwind is normal practise, and hugely exhilarating. Johneapriddle (talk) 22:24, 6 July 2011 (UTC)

Major deficiency in this article

This article ignores completely the possibility of broaching in a powerboat. This is something that is well covered in the tuition and literature on powerboating. Whilst the article covers just broaching in a sailing vessel (which does not seem a good idea to me), this deficiency also highlights the minimal emphasis given to the effect of wave action in causing a broach in a sailing vessel - this is dangerously misleading. Whilst Wikipedia is not a manual (WP:NOTMANUAL), it is a source of knowledge, and omitting this cause of a broach is therefore wrong. Most readers would take away the opinion that a broach is largely the result of wind action. The article should cover the rotational effects within a wave and the poorer directional stability of any vessel as it reaches the crest of a wave. Anyone disputing the opinions given here may want to take a look at the External Links in the article before answering.

Overall, I think this entire article could do with a rewrite. ThoughtIdRetired (talk) 20:40, 10 November 2019 (UTC)

It might make sense to differentiate between a "spinnaker broach" and one where wave action has a larger influence. The term "spinnaker broach" is used by Practical Boat Owner, a magazine that I have always thought a source of authoritative good sense. I am still looking for a RS on the rotational movement within a wave that reduces the effectiveness of the rudder when a boat is going over the crest - this is more than a simple lack of immersion issue. ThoughtIdRetired (talk) 15:19, 4 December 2019 (UTC)

Wave action as a cause of broaching

The lead of this article has just been changed - but still completely ignores the effect of wave action as a cause of broaching. Given that this is not some subject that safely stays in the library, but is information that people might need to keep them safe, I think it is important for Wikipedia to get this right.

I agree that the subject-matter has been muddled by the racing fraternity and the "spinnaker broach". However, every sailing boat and every power boat (and for that matter, commercial craft like fishing vessels and, in extreme conditions, large modern ships) are all exposed to the risk of broaching solely due to wave action.

May I please ask anyone who edits this article to look at the three external links on broaching? This should give you some understanding about the way wave action can cause a broach.

Can anyone suggest how the deficiencies of this article are highlighted to editors who might be able to give it a complete (and safe!) treatment? It horrifies me that Wikipedia - as a source of knowledge - is failing to provide an accurate article on a subject where knowledge might keep you alive.ThoughtIdRetired (talk) 17:26, 31 May 2020 (UTC)

Thank you for posting here, ThoughtIdRetired. We and the readers must bear in mind that Wikipedia is an encyclopedic reference, not an instruction manual, guidebook, or textbook, as you said, above. I simply fixed some poor writing with my edit. You, of course, are welcome to improve the article further. Bear in mind that the article title is "Broach (sailing)", so it's not surprising that the scope is as limited as it is. It would be fine to describe other types of broaches for other types of vessels, as you suggest, in a separate section. Cheers, HopsonRoad (talk) 19:36, 31 May 2020 (UTC)

Update: I pared the article down to its essentials. See what you think and where more detail would be beneficial. Cheers, HopsonRoad (talk) 21:46, 31 May 2020 (UTC)

Thanks HopsonRoad for tackling this. The sort of source that I am looking for is something that goes into some detail about the concept covered by this sketch (apologies for the poor quality of the draughtsmanship):

Rotation in a wave and broaching

The concept shown in the sketch is that in order for a wave to form, water particles have to move locally within the wave. This movement is rotational. As a boat travels down the face of a wave, given the right combination of waterline length and wavelength, the rudder will be in the part of the wave that is moving forward. (This is a more hydrodynamically accurate concept than "the waves are going at the same speed as the boat".) This means that the rudder does not have a decent flow of water in which to produce a turning moment in response to input from the helmsman. At the same time, the boat may be subject to forces that provide a turning moment. These may include: the bow "digging in" to the back of the next wave ahead; a quartering sea pushing on the side of the stern; wind effects (in both power and sailing vessels).

What is needed is an RS that confirms my recollections from lectures and books (to which I no longer have access). I note that the article now uses Basic Ship Theory as a source - but this is the 1976 version. Am I right that this has since been updated? - or does it address this matter anyway. I note that there has been a substantial body of work encouraged by the IMO on broaching which appears to my inexpert opinion to have provided some effective models for predicting broaching. The point also occurs to me that this recent work may make my recollections of the theory of broaching obsolete. Hence the need for a good recent source that covers this matter. Not sure how much my contribution moves things along - it would be great to have access to the latest version of Basic Ship Theory.ThoughtIdRetired (talk) 20:39, 1 June 2020 (UTC)

Thanks for adding a further dimension to the question, ThoughtIdRetired. As I understand your commendable diagram, even if the rudder isn't lifted from the water, the forward rotation of water within the wave can slow the water down with respect to the rudder and render it ineffective. I'll see what I can do to elucidate that further. Cheers, HopsonRoad (talk) 00:34, 2 June 2020 (UTC)

Update: That's actually what Basic Ship Theory explained on P. 562! Cheers, HopsonRoad (talk) 00:45, 2 June 2020 (UTC)

Propose moving to "Broach (nautical)"

I propose moving this page to "Broach (nautical)", because it's not just about broaching a sailboat, but also about broaching any vessel. HopsonRoad (talk) 14:46, 2 June 2020 (UTC)

adequate redirects and material added to item to explain the context I see no problem... JarrahTree 02:43, 3 June 2020 (UTC)

Makes good sense to me.ThoughtIdRetired (talk) 08:20, 3 June 2020 (UTC)

Support Should probably have a redirect from "Pitchpole", too. But I have no problem with this proposed move. Cheers. 7&6=thirteen (☎) 19:07, 3 June 2020 (UTC)

 Done I have edited many links to this page. HopsonRoad (talk) 02:08, 4 June 2020 (UTC)

Broach_(nautical): introductory paragraph

The following has been copied from User talk:ThoughtIdRetired

Hi,

Regarding Broach_(nautical):

I think that your recent additions to the introductory paragraph make it less helpful because they attempt to cover too many concepts. This both makes the introduction more verbose and fails to do justice to those concepts. Remember that an introductory paragraph serves to introduce a concept to people outside a domain. So the explanation must avoid specialized vocabulary.

Please consider restoring the introductory paragraph to its previous, short version.

--Black Walnut (talk) 03:20, 9 July 2020 (UTC).

@Black Walnut: I have had a go at a "hybrid" version of the lead. Do you think this does the job?

Generally, I feel the article could do with a bit more content, but it is difficult to find good sources. There are many yachtsman's books, many of which seem to be completely unaware of the hydrodynamics of wave induced broaching. (And few of them seem to mention the unseaworthy design element of modern yachts: broad transoms with flat floors aft lift the rudder out of the water when heeled.) In contrast, the IMO has sponsored and encouraged a lot of work on the technical aspects of wave-induced broaching - but I have only been able to find very technical research papers on the subject. If I don't understand the mathematics in those papers, I should be wary of using them as a reference. What I do know is that broaching is a very real risk for powerboats - particularly small craft entering harbour. ThoughtIdRetired (talk) 07:58, 9 July 2020 (UTC)

Thank you! Your latest version is a significant improvement.

I also agree that the article would benefit from expansion. Actually, it was much longer a decade ago. It even included advice on sailing technique. I haven't looked closely into how all that material vanished. Collecting and reintroducing some of it could be worthwhile. I believe it included references.

Some remaining problems in the article's introduction:

• Your latest version introduced some specialized terminology: "beam" and "on to the sea". We must avoid domain-specific terms if we can find words which non-sailors can understand. Especially in an introduction. Also, for most people, "moment" conveys a unit of time. "momentum" may be a better choice, since it is unambiguous.

• What about sailing down-river? Is the loss of control, caused by matching the river's motion, not a form of broaching? That is still water action but it isn't caused by waves. Here is a new draft sentence for the introduction. What do you think?

If the rudder is surrounded by water whose motion (due to waves, tides, or currents) approximates the vessel's own, then the rudder's relative speed through that water is reduced.

• Does broaching leave the vessel beam to the wind or does the vessel turn into the wind? The intro claims both, which is confusing. If the end result depends on the interaction between wind, swell, and the specific vessel's hydrodynamic and aerodynamic properties, then the end result is too complex a matter to raise in the introduction.

• Looking at my own last version, I now think that I should have removed the distinction between power and sailing vessels. Your recent edits inherited this distinction. I think it would be better to leave this to the article's body, where we can do it justice.

--Black Walnut (talk) 17:16, 9 July 2020 (UTC).

Possible rewrite of
"The loss of control from either cause usually leaves the vessel beam on to the sea, and in more severe cases the rolling moment may cause a capsize."
would be
"The loss of control from either cause usually leaves the vessel beam on to the sea (with the boat pointing at right angles to the direction of travel of the waves). In more severe cases the momentum of the rolling action that is involved may cause a capsize."

Not aware of any down-river risk of broaching - do you have a source that addresses this?

When thinking about the water flow over the rudder, tides and currents are irrelevant because the "closed system" is the boat in the water - if the whole system (boat plus water) is moving due to, say, a fast tide, that has no relevance to what we are considering.

The resultant position: beam on to wind or sea. This is one of the fossils in the article from when it just considered wind action. Some thought needs to be applied to this.

Distinction between sail and power vessels. I think this is where Wikipedia cannot work in isolation from the way others write about the subject. There is so much written in the yachting press about wind-derived broaching that there needs to be some separation of the subject of wave action broaches. The simplest ways to talk about this is to use the term "power boat". I feel that this will trigger the highest level of understanding by readers with any boat-handling experience. The IMO has done extensive work on the subject of wave-action broaches - it has important commercial relevance, especially in fishing vessels. Any streamlining of the article on this aspect should be done with extreme care not to blend the 2 subjects to the extent that it is not obvious to the reader that there are 2 subjects. (Taking on board the point that "Wikipedia is not an instruction book" - we still need to consider that Wikipedia is providing information on a subject where lack of knowledge can easily kill you. Whilst sailing yachtsman have probably heard of broaching and may know how to reduce the risks, power-boat owners may be completely unaware of the subject.)ThoughtIdRetired (talk) 20:53, 9 July 2020 (UTC)

end of text copied from User Talk:ThoughtIdRetired#Broach_(nautical):_introductory_paragraph - please continue any discussion here on the article talk page

User:ThoughtIdRetired proposed this sentence:

"The loss of control from either cause usually leaves the vessel beam on to the sea (with the boat pointing at right angles to the direction of travel of the waves). In more severe cases the momentum of the rolling action that is involved may cause a capsize."

How about this, instead:

During a broach, the vessel tends to turn, exposing one of its sides to the acting force (wave or wind), which can then capsize (overturn) the vessel.

Regarding the distinction between sail and power vessels: I didn't say that we should omit the material. I only proposed to leave those distinctions for the article's body. We could even have distinct sections, if that helps.

I lack references for down-river broaching, so I'll drop that matter.

--Black Walnut (talk) 00:08, 10 July 2020 (UTC).

Looking at the 2 alternative sentences for the lead, I would be keen to follow the cited source. This is where we have talk about the "rolling moment". The precise quote is: "The vessel might even capsize due to a large roll moment arising from the forward momentum and the large heading angle. The effect is greater because the ship's hydrostatic stability is often reduced by the presence of the waves." (Incidentally, I believe there is a typo on the ref - should say "...and the large change of heading angle....".) So what we could be trying to convey is that a ship rolls during broaching, possibly resulting in capsize, as a result of the abrupt turn and the shape of the waves around the heeled hull - which is possibly a bit too much detail for the lead. What I think we should settle for is a more minimalist version - and it is the sudden change in heading that is the major initiator (the forward momentum would have no harmful effect without the rapid yaw of the vessel). I am hesitant to pick either of the 2 current offerings as a good way of dealing with these requirements, but feel that my own offering is, at least, adequate.

The argument for a clear mention of both power and sailing vessel broaches in the lead is that many people who read Wikipedia often do not go beyond the first paragraph or two. This is the only opportunity (with such readers) to get across the the major points. The lead is already quite concise - I don't see a need to thin it down any more.

Incidentally, here is a quote from a research paper on mathematical modelling of broaching
"Broaching is a phenomenon in which a ship cannot maintain a constant course despite the maximum steering effort being applied. Broaching often occurs when a ship is surf ridden on the downslope of a stern-quartering wave, which induces significant yaw moment. The centrifugal forces resulting from this violent yaw motion can result in capsizing. This presents a real threat to high-speed vessels such as destroyers, high-speed RoPax ferries, and fishing vessels."
Umeda, N., Usada, S., Mizumoto, K. et al. Broaching probability for a ship in irregular stern-quartering waves: theoretical prediction and experimental validation. J Mar Sci Technol 21, 23–37 (2016). https://doi.org/10.1007/s00773-015-0364-8
Here again I would emphasise that a source talks about the "violent yaw motion" - it is the sharp turn that starts the roll that can end up with a capsize. Note that even something close to 90 degrees of roll as a result of such a sudden yaw can easily result in a man-overboard situation. (We have only considered capsize as the serious hazard so far.) Without (I hope) being over-dramatic on the point, such a man-overboard is something that kills people - a pleasure power-boater making a harbour entrance in moderately rough conditions can (and has) lost lives in this way. In rough water and a shallow entrance I have sent a crew member forward under strict instructions to clip on, with risk of broaching in mind. A year or so later, a power boat lost a child overboard in the same spot under similar conditions (with no good result). At about the same time, the next harbour along the coast had a fishing boat broach on running for shelter. All were lost. It was a sombre moment, on a calm day a week or so later when we saw the Trinity House tender lay a wreck buoy over where she lay. Hence the importance of getting this right. ThoughtIdRetired (talk) 20:48, 10 July 2020 (UTC)

Some marine accident investigations mention broaching. These include: [1], [2]ThoughtIdRetired (talk) 22:38, 10 July 2020 (UTC)

@ ThoughtIdRetired:

I understand your desire to increase awareness of a matter which has caused loss of life in your community. I agree that the article should do justice to the topic, by covering the matter thoroughly and by including advice and published findings from researchers.

However, we are putting the cart before the horse. An introduction should summarize the article, not be the article. We are silly to debate wording for the introduction about material that isn't yet in the article's body.

Let's write good sections for the article, to cover the issues which you raised. Then, we can summarize those sections in the introduction.

To address your concern that the introduction should caution novice sailors, and to use plain language, which inexperienced sailors and non-sailors can readily understand, I propose to replace the article's introduction with the following 2 paragraphs:

A broach is a dangerous situation, in which a vessel turns involuntarily and abruptly. Steering becomes unresponsive, the vessel swiftly exposes one of its sides further to the wind or waves, and ends up leaning dangerously on its side. Broaching is caused by wind or by waves.

A broach can happen in mild weather. It can quickly escalate into rolling (swinging from side to side), throwing crew members overboard (off the vessel), and capsizing (overturning).

I am uncomfortable with the second paragraph: the article's body covers these matters sparsely. I include it only to assuage your safety concerns. If we do include it, we must substantiate it with material in the article's body.

--Black Walnut (talk) 01:04, 21 July 2020 (UTC).

Not going to be able to do justice to your comments today as really busy outside Wikipedia, and your remarks will need detailed study to produce a useful answer. Just quickly, where do you get the "A broach can happen in mild weather" from? - hopefully not from my narrative of seeing the Trinity House tender laying a wreck buoy a week or so after the loss of a fishing vessel. Generally, you need either wind or waves (and probably both) for a broach to occur. I'll be back on this subject a.s.a.p.ThoughtIdRetired (talk) 07:48, 21 July 2020 (UTC)

@ ThoughtIdRetired:

Thank you for your quick response. No worries. Get to it when you get to it.

Regarding "mild weather": my intent is to caution the overconfident. There is evidence: the article's third external link (a short film) includes an example at 2m24s which, certainly to an inexperienced eye, appears as nice weather. YouTube: powered vessel, wave broach, sunny, ~1.5m waves, near harbour. Again, the article's body must be augmented to detail all that -- we can't just add a statement to the intro and stop there. I would be happiest if we omitted this paragraph altogether until the body has that content -- with citations.

--Black Walnut (talk) 18:38, 21 July 2020 (UTC)

On starting to look at this again, User:Black Walnut's assessment of "mild weather" for the video on youtube is, I think, a debatable point. I have seen this video before and did not think the conditions were mild - there seemed to be a significant swell. The problem is the angle from which it is viewed (and that is part of the subject). The video is used in [3] at 24 minutes in, and the effect of shallow water on waves is mentioned. The accident report referred to above mentions the difficulty of accurately judging the severity of waves on approach to harbour. You often don't know the conditions are bad until you are in them - again as is clear from the discussion in the accident report.

That also leads into the "not how-to" comments below, with which I agree. The challenge is to produce an article about a dangerous situation without being an article on how to deal with those dangers. Deciding on the boundaries between the two is a bit of a challenge.ThoughtIdRetired (talk) 16:50, 22 July 2020 (UTC)

Not how-to

In reading some of the discussion, above, I'm concerned that there may be a tendency for the article to return to having "how-to" or "how not-to" cautions. This article is to inform the general public. I recommend directing people seeking instruction to Further reading or Outside links sections. Cheers, HopsonRoad (talk) 00:34, 22 July 2020 (UTC)