Wide-open discussion of the loss of Low Speed Chase

[estarzinger]

To clarify, I used the average height multiplier for the 10% and 1% numbers (1.27 and 1.67, respectively), and while admittedly conservative, I feel they do provide a reasonable reference point for making prudent decisions.

That's fine, so long as you understand the implication of the numbers - eg that they are in fact NOT the heights of the 1 in 10 and 1 in 100 waves, but of the average of waves bigger than the 10% and 1% waves . . . just for your reference the 1.27 multiplier matches the height of about the 4% wave and the 1.67 is about the .4% wave.

Besides, I would be surprised if the depth of water shown on the charts is close to within 4' in some places,

That's interesting. I would have expected the charted depths on the course to be within 1' accurate (of course taking into account the chart depth datum). Out of curiosity, do (or anyone else here) you have any specific observations suggesting 4' errors along that course (or elsewhere in the SF racing area)?

Another discussion is whether you should have a cockpit display showing the depth, or just rely on the plotter/charted depths.

Moreover, I wouldn't care to be that precise in selecting a reference point anyway, since I will continue to do exactly what you suggest and 'feel the waves' before choosing how close I'll get.

Excellent. The trick here is to realize that as you come from the east bar to the west bar (or the other way) and are looking in at the shallow water (eg 'VFR navigation') you may well not see a .4% wave happen, so you may not see the potential 'breaking wave zone' with an actual breaking wave. The implication is that you need to be more sensitive to looking at wave shape and size to judge (and not just looking for breaking) where the potential breaking wave zone in fact is.

 

[us7070]

Excellent. The trick here is to realize that as you come from the east bar to the west bar (or the other way) and are looking in at the shallow water (eg 'VFR navigation') you may well not see a .4% wave happen, so you may not see the potential 'breaking wave zone' with an actual breaking wave. The implication is that you need to be more sensitive to looking at wave shape and size to judge (and not just looking for breaking) where the potential breaking wave zone in fact is.

this approach seems to require a familiarity with the conditions at the island, and the potential danger spots in particular, that might not really be achievable, given that people race there maybe once a year, and are only over the bars for a pretty short time.

 

[Naviguesser]

To clarify, I used the average height multiplier for the 10% and 1% numbers (1.27 and 1.67, respectively), and while admittedly conservative, I feel they do provide a reasonable reference point for making prudent decisions.

That's fine, so long as you understand the implication of the numbers - eg that they are in fact NOT the heights of the 1 in 10 and 1 in 100 waves, but of the average of waves bigger than the 10% and 1% waves . . . just for your reference the 1.27 multiplier matches the height of about the 4% wave and the 1.67 is about the .4% wave.

Besides, I would be surprised if the depth of water shown on the charts is close to within 4' in some places,

That's interesting. I would have expected the charted depths on the course to be within 1' accurate (of course taking into account the chart depth datum). Out of curiosity, do (or anyone else here) you have any specific observations suggesting 4' errors along that course (or elsewhere in the SF racing area)?

Another discussion is whether you should have a cockpit display showing the depth, or just rely on the plotter/charted depths.

Moreover, I wouldn't care to be that precise in selecting a reference point anyway, since I will continue to do exactly what you suggest and 'feel the waves' before choosing how close I'll get.

Excellent. The trick here is to realize that as you come from the east bar to the west bar (or the other way) and are looking in at the shallow water (eg 'VFR navigation') you may well not see a .4% wave happen, so you may not see the potential 'breaking wave zone' with an actual breaking wave. The implication is that you need to be more sensitive to looking at wave shape and size to judge (and not just looking for breaking) where the potential breaking wave zone in fact is.

In fact, it's quite unlikely during an approach to the bar that you would see the 0.4% wave, considering that they would occur about once an hour with a 14 second period according to the report. So, unlike flying VFR where you can actually see the clouds you want to stay out of, you have to know the area of likely breaking waves for the conditions and ensure that you're out of that zone. Besides, the difference that we're speaking of is only a couple of hundred yards, a inconsequential difference in course distance on a 58 nm race.

In any event, the one thing that this incident should teach us is that this is one corner not to cut too close!

 

[estarzinger]

The implication is that you need to be more sensitive to looking at wave shape and size to judge (and not just looking for breaking) where the potential breaking wave zone in fact is.

this approach seems to require a familiarity with the conditions at the island, and the potential danger spots in particular, that might not really be achievable, given that people race there maybe once a year, and are only over the bars for a pretty short time.

hmmm . . . perhaps . . . but the location of the 'problem area' is well known, and there WILL definitely be wave shape/size indications at a much higher frequency than the actual breaking waves. And in fact LSC did definitely encountered (according to the survivor reports) an 'early warning' wave between the bars.

The alternative (suggested by several in posts above) is just to pre-set a course 'well outside' (make a very conservative depth/wave forecast calculation). That probably gives up 5-10 boat lengths of distance. For some boats that will be an excellent trade-off, but others would (for instance) pay their sailmakers anything to get a guaranteed 5-10 boat lengths and will definitely want to round this corner as closely as 'prudent' and the wave size/shape judgement is the way to do that. Of course I agree that if you are going that route you need some decent experience with waves, and some decent experience with this corner would also be very useful.

Beyond the extra distance, another 'problem' with the completely 'pre-computed' rounding depth is that when you get out there the waves may well not be as forecast. This is just simply not a cookie cutter task. You really need to exercise seamanship/judgement . . . and experience/knowledge is certainly rather useful in being able to do so.

You can in fact 'usually' cut these bars. Both historical experience shows that (many boats have cut them in the past) as do the theoretical breaking wave calculations. According to the report's 'conservative' calculation, you could take LSC's course across the bars in up to 11' significant wave heights (Which is within the 2 sigma wave probability band), and generally that's in agreement with the race history. The problem for LSC was that the waves last year were rather bigger than 'typical' (outside the 2 sigma band - as shown in posts above with the actual buoy wave measurements), and the 'safe' history of cutting the bar could not (should not) be applied.

By the way, you will find that most people involved in this topic have been told by their lawyers to shut up and not discuss it because of the lawsuit. I have also been told that . . . but I don't think it is helpful to the sailing community or to all of us learning as much as we can from each other and from the report and from prior experiences in the race. So, I continue to engage in discussions about the topic in order to try to further understanding and safety. But of course all I say is my opinion only.

 

[us7070]

"judgement and seamanship" to me, means experience, and the ability to use that experience wisely.

one thing we have learned is that this place is somewhat unusual, and while there may be some sailors who have a lot of experience with this location, I think many racers will not have much experience here - afterall, they mostly only go there in a race. it's not as if they are cruising there with the kids on weekends. also even, people with experience had to start somewhere.

Your comments indicate that a boat could substantially reduce risk by adding about 30 seconds to their elapsed time in a ~7 to 11hr race.

I navigate - and that seems like a good trade off, especially knowing what I know now about the dangers there.

 

[estarzinger]

"judgement and seamanship" to me, means experience, and the ability to use that experience wisely.

Experience is certainly one way (and perhaps the 'best' way) to gain that judgement and seamanship (and taking some 'practice sails' out around the island would certainly be useful . . . as should be hiring an experienced pro skipper as the LSC owner did . . . ). But there is also certainly a 'hope' that some can be gained/learned in other ways . . . seminars, talking to other sailors, understanding the 'physics' (as in the wave dynamics), videos, etc.

Your comments indicate that a boat could substantially reduce risk by adding about 30 seconds to their elapsed time in a ~7 to 11hr race..

That is certainly one valid way to look at it. But the other is that 5 -10 boat lengths are still 5-10 boat lengths, which might make the difference between first and third, and the competitive teams will be looking for every boat length they can find. It really depends on your trade-off between competitive appetite vs risk. . . . as do many other things in racing (like how much wind to fly a chute in, or when to have only your very best helm on the wheel, or in what conditions to not start or to retire in).

 

[us7070]

Your comments indicate that a boat could substantially reduce risk by adding about 30 seconds to their elapsed time in a ~7 to 11hr race..

That is certainly one valid way to look at it. But the other is that 5 -10 boat lengths are still 5-10 boat lengths, which might make the difference between first and third, and the competitive teams will be looking for every boat length they can find. It really depends on your trade-off between competitive appetite vs risk. . . . as do many other things in racing (like how much wind to fly a chute in, or when to have only your very best helm on the wheel, or in what conditions to not start or to retire in).

It's not often that 30 sec of elapsed time is one place in a 10hr race, let alone two places. now before everyone starts giving examples to the contrary - It certainly does happen, and I've seen 30 seconds be the difference in much longer races than this.

nevertheless, nobody wants to give up 30 seconds

It's generally been my experience that the more competitive sailors take fewer risks (both in terms of tactics, and in terms of safety) than less competitive boats - because they know that they can win without doing so.., just by being good.

of course, in a handicap race, everything is a bit of a crapshoot anyway.

 

[jhc]

LSC was not contesting for first, or third. This was not a case of over the top competitive action. Was simply in the wrong place, at the wrong time.

The first, and third place boats were able to navigate the island successfully.

This idea that to be competitive, you must take enormous risk, is a notion that is perpetuated by people who have no idea what competition is.

 

[estarzinger]

The first, and third place boats were able to navigate the island successfully.

Well . . . the 1st place boat in class PHRO3 was the boat that followed exactly in LSC's path cutting across that bar.

LSC was not contesting for first, or third. This was not a case of over the top competitive action.

We were talking about how to plan future roundings and not specifically about LSC's decision. However, I would suggest that even though LSC blew their start and were not contesting for the front of the fleet, they were still sailing 'competitively', going as fast as they could and saving as much distance as they could.

This idea that to be competitive, you must take enormous risk, is a notion that is perpetuated by people who have no idea what competition is.

The notion that sailing entails risks is plain fact. You are the one that added 'enormous', I never did. And if you are suggesting that I don't understand competition then you don't know my background . . . you ever been an NCAA all American or on an Olympic team??

 

[JustDroppingBy]

Well . . . the 1st place boat in class PHRO3 was the boat that followed exactly in LSC's path cutting across that bar.

Yes, they did just that, successfully, and not that long after LSC's mishap from an elapsed time perspective. Give it 2 or 3 years and everyone will be right back on that track, perhaps closer even, and since the odds don't favor another crash, it will probably be fine.

If it's not, that's the way it goes, racing, yachting, climbing, jumping from perfectly good airplanes - they all have an inherent risk factor and the law of averages is not called a law for nothing. There's the solo guy off Tasmania who may be in real trouble, should we stop solo racing, wipe Tasmania off the map or hang the mast builder because the rig fell down?

All the talk about how competitors aren't risk takers and 30 seconds yada yada is just silly talk really. Ask Lance Armstrong if you don't believe me.

And Evans, just for the record, the fellow who goes by naviguesser is hardly guessing, with his engineering or his sailing judgement, that bit is assured by his results and background.

 

[One eye Jack]

There are three types of people. The one that learns from others mistakes, the one that will learn from their own mistakes, and those that never will learn. The last two may have a bit shorter life span.

Everybody's talking about the extra time to round the island if they don't go inside.. They say maybe 15 boat lengths . And how much time will you loose when you end up like low speed chase? Or when you go home and you round up once or twice?its funny how the turtle beat the hare.

 

[K38BOB]

Well . . . the 1st place boat in class PHRO3 was the boat that followed exactly in LSC's path cutting across that bar.

Yes, they did just that, successfully, and not that long after LSC's mishap from an elapsed time perspective. Give it 2 or 3 years and everyone will be right back on that track, perhaps closer even, and since the odds don't favor another crash, it will probably be fine.

If it's not, that's the way it goes, racing, yachting, climbing, jumping from perfectly good airplanes - they all have an inherent risk factor and the law of averages is not called a law for nothing. There's the solo guy off Tasmania who may be in real trouble, should we stop solo racing, wipe Tasmania off the map or hang the mast builder because the rig fell down?

All the talk about how competitors aren't risk takers and 30 seconds yada yada is just silly talk really. Ask Lance Armstrong if you don't believe me.

And Evans, just for the record, the fellow who goes by naviguesser is hardly guessing, with his engineering or his sailing judgement, that bit is assured by his results and background.

Actually skippers meetings are one way to keep lessons learned alive, so are other education venues

other participants talked to recently mentioned above are certainly permanently enlightened...aren't you?

(glad to see you feeling better)