Heavy weather, can we be honest?

[barnakiel]

I have just read a featurette in YM devoted to an Aussie skipper on his way to the 2018 "Golden Globe" race. Boat Tradewind 35. Rolled and abandoned off Chile. Skipper rescued by a Chinese cargo.

I wonder what sort of insurance the participants will carry. I can see plenty of entertainment for me watching the event from an armchair. Those brave romantic people in their least adequate boats, heavy weather, rogue waves, shark infested waters ...

b.

[conachair]

Unknown source..

: “The good seaman weathers the storm he cannot avoid, and avoids the storm he cannot weather.”

[Paul L]

Originally Posted by estarzinger

Years ago, they were trying to charge for stuff you could easily get for free and better elsewhere (gfs, plus a pretty poor GUI). That developed a poor 'reputation' among the 'in weather crowd'. It was viewed as the place people went who did not know any better, which has persisted . . . . however they have improved a lot since those days, including the euro model which is somewhat hard to get elsewhere and a much better GUI.

A poster came on here claiming how he discovered Predictwind and how much more accurate it was than the GRIB files - seemingly having no clue it was a visualization of the the standard GRIB models. That generated some comments.

The ECMWF model is freely available at http://www.windy.com

[Cadence]

I believe the OP was making light of some exaggeration about sea and wind conditions.
Someone made it analogist to how big the fish was.

The 14ft. seas become 20. 20 kn. winds become 30.

I Guess it is human to remember it that way.

[Kenomac]

Originally Posted by Dockhead

Sorry for the thread drift, but what's the criticism of Predict Wind? I don't understand.

We use GFS model gribs from Passage Weather. This is raw model output from, I believe, NOAA, and once you have some experience interpreting them, they are excellent, giving you a very good picture of the wind (subject to those things you know to interpret about them) up to three days out, and a decent idea of the general flow for a few more days out than that. It seems to me that the model keeps improving, as the data seems to be better than it was 10 years ago or whenever we first started using it.

As good as they are, I would never use raw gribs alone if I have access to human weather forecasts. So I always get an official maritime weather forecast when it's available, or weatherfax for the big picture.

But I believe Predict Wind gives the same GFS gribs as everyone else -- what is wrong with them?

Originally Posted by Paul L

A poster came on here claiming how he discovered Predictwind and how much more accurate it was than the GRIB files - seemingly having no clue it was a visualization of the the standard GRIB models. That generated some comments.

The ECMWF model is freely available at http://www.windy.com

An example of what I was referring to.

[Snowpetrel]

Originally Posted by Kenomac

An example of what I was referring to.

Wow, you do have a thin skin...

[Palarran]

Originally Posted by Kenomac

You're saying that you've never ever sailed in what what my wife and I now consider to be relatively benign conditions like in this video, yet you persist in your opinion that all boats are basically the same except for the quality of the seat cushions in your other posts.

We're making 8 knots in 28-32 knots of wind with just the staysail.

Is your motor running like in the other videos you posted?

To the OP,
Is this the type of comments you started this thread about?

[Snowpetrel]

One reason I think wave heights get so exagerated is the difficulty assessing the true height once they get over your height of eye. Here is a terrible drawing of one likely reason fpr this. I typically assess it by eye and half my estimate. This seems about right most of the time. Probably 55-60% of your estimate is the actual wave height.

The only really accurate way to assess bigger waves is by using the horizon and standing higher and higher until you can just see the horizon on most of the waves. Then work out your Height of eye from the waterline.

[Diesel Bill]

Originally Posted by donradcliffe

Yes. sailors like to spin yarns, and sometimes truth is victim to a good story. I was enjoying Diesel Bill's yarn until he got to the fierce tidal currents around Santa Cruz, which max about at 1 knot. Indeed, the Santa Cruz harbor entrance is closed by shoaling by mid-January in most winters, so perhaps he also lost track of the date.

I apply surfer's rule to most wind reports from cruisers--divide by two and add one. I remember Archie from South Africa reporting on the SSB net 'mountainous waves and 30+ knots' when he had to beat back against the trades to Raiatea. We were anchored inside the reef at Mopelia and could see him out there--battling into less than 15 knots and 2 meters.

Personally, I can count on one hand the number of times I have seen sustained winds (not gusts, not squalls) of over 40 knots in over 150,000 miles of sailing.

Hi Don, I felt I had to reply. Not trying to start an argument. I never mentioned fierce tidal currents. What I said was the outgoing tide overpowered my little boat. As we were about 5 miles off the entrance and I ran the engine at 3/4 throttle for about an hour
and made no head way getting any closer to shore and we were exhausted it was easier to wait for the tide to turn and get some sleep. We arrived late Jan. or it could have been early Feb. At any rate we road large swells into the harbor. We stayed 2-3 months and had a great time although the wife was done with sailing.
By the way this was right around 40 years ago so I can't say what the exact day was or what I had for dinner the night before. That's my story and I'm sticking with it.

[Paul L]

Originally Posted by Snowpetrel

One reason I think wave heights get so exagerated is the difficulty assessing the true height once they get over your height of eye. Here is a terrible drawing of one likely reason fpr this. I typically assess it by eye and half my estimate. This seems about right most of the time. Probably 55-60% of your estimate is the actual wave height.

The only really accurate way to assess bigger waves is by using the horizon and standing higher and higher until you can just see the horizon on most of the waves. Then work out your Height of eye from the waterline.

Attachment 149073

Well I kinda like the drawing. I think the preception error is more direct than your 2x line. If you added a line that runs the face of the wave it might represent what people are looking at. Surfers, especially rookie ones, are always over stating wave height by looking more at the wave face.

[Diesel Bill]

I judge a wave height by distance from bottom of trough to top of crest. Is this wrong?
If you can't see the horizon due to sea state and sitting only 3 feet or so above the water All you can do is try to get a best guess estimate. I try to see how much water is above me by looking at the mast and comparing to a known height.

[Snowpetrel]

Originally Posted by Diesel Bill

I judge a wave height by distance from bottom of trough to top of crest. Is this wrong?
If you can't see the horizon due to sea state and sitting only 3 feet or so above the water All you can do is try to get a best guess estimate. I try to see how much water is above me by looking at the mast and comparing to a known height.

The problem is trying to accurately assess when you are at the bottom of the trough, your sense of gravity, and true up and down gets screwed up in bigger waves, and its so easy to misjudge. I think Pauls logic makes sense too, and you tend to think the face of the wave is the height.

I occasionally try to assess it accurately in bigger waves by climbing up onto a dodger or up some ratlines, and the results are disappointing, and follows the half rule pretty well.

In my drawing, for the poor guy on the helm it looks like the wave is towering over his boats mast. In reality its only half way up his mast.

[Diesel Bill]

So when measuring for true wave height imagine an alternating current (AC) wave form.
the zero line is in the middle of the sine wave with 1/2 above the line and 1/2 below the line. So the wave is only 1/2 of the whole from top to bottom? Is this right. If this is correct then my huge waves of 25-30 ft were only 12-15 ft?

[TJ D]

To the OP,
Is this the type of comments you started this thread about?[/QUOTE]

Well, not exactly, but there's been some great input here, and it seems like most folks with a lot of offshore experience tend to more or less line up with my experience.

And, hey, it's CF! I've learned that there's always going to be some elbows getting thrown around here.

Part of the charm? I don't know. I sort of filter that stuff out and focus on the meaningful posts.

All in all, it's been a good thread, methinks.

TJ

[TJ D]

Originally Posted by Snowpetrel

One reason I think wave heights get so exagerated is the difficulty assessing the true height once they get over your height of eye. Here is a terrible drawing of one likely reason fpr this. I typically assess it by eye and half my estimate. This seems about right most of the time. Probably 55-60% of your estimate is the actual wave height.

The only really accurate way to assess bigger waves is by using the horizon and standing higher and higher until you can just see the horizon on most of the waves. Then work out your Height of eye from the waterline.

Attachment 149073

This is s good point. I spend lots of time in big seas, somewhere between 20 and 40 feet above the water or thereabouts. Perspective has a lot to do with sea height estimates. Seas do look much bigger when your butt is right on the water.