"Sailing" on the hook

[Kenomac]

Originally Posted by Snowpetrel

https://youtu.be/uJSpMtc8SrU if you want to see some real wind at anchor skip to 2:20 logged at over 90 knots average by a nearby 1km away weather station. I think you need to get your windspeed indicator calibrated properly. I have seen a few of your videos where you claim strong winds that are obviously only the peak gusts not the ten or even the 3 minute average, a common novice mistake.






Have a good hard look at your post count before you start calling other people internet experts...


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Impressive video. Maybe you should heed your own advice and not make snap judgements on other people and maybe share more instead.

Our windspeed indicator is correctly calibrated as I'm sure your's is too.

Keep the videos coming.

Ken

[Jim Cate]

Our windspeed indicator is correctly calibrated as I'm sure your's is too.

Ken, how did you calibrate your anemometer? Not an easy thing to do IME.

Jim

[Kenomac]

Originally Posted by Jim Cate

Ken, how did you calibrate your anemometer? Not an easy thing to do IME.

Jim

The meter on our previous Hunter was way off, so since then I've always had at least one handheld meter on board to double check when I have doubts. Seems to work for us. But no, other than double or triple checking (this boat came with another handheld), it hasn't been done professionally if there even is such a thing.

[GILow]

Originally Posted by Jim Cate

Ken, how did you calibrate your anemometer? Not an easy thing to do IME.

Jim

I moored 100 meters from the offshore weather observation tower here in Adelaide (called, somewhat unoriginally, "Black Pole") and checked our readings against their 15 minute updates using my phone. Not perfect but it seemed to suggest we were close enough for practical purposes at the 10 to 15 knot range. Didn't stick around to test it at higher speeds though.


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[peter57]

Originally Posted by GILow

Edit: oh, I see, yes when wind and current are against each other she will move around. But surely just about any boat is going to do that at some given relationship between wind and current.

I thought this was about the effect of wind on the boat at anchor. I regularly anchor under the breakwater at outer harbour where there is no measurable current, and in those conditions we point steady as a rock to the wind in all conditions I have anchored in so far. That's from calm to about 25 knots.

Ignore from here on down.

Weird. Has not done it to me yet. American river has a VERY strong current, she was steady as a rock. The only problems I had with movement was when I was caught down there in a strong northerly, 30 knots or so, and when the current and wind were at odds with one another we moved around a bit. Was it a 42 or a 38 you were travelling with? They look very similar from the outside.


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Hi Gilow,

42 ft "tardis" I tried to buy the boat myself and she only played on the anchor wind against with the rest of us. The 43" S&S Huon Pine splined I use to own was also built by Ron Swanson 1961 she is in Gove at the moment.

Cheers,
Keep on Sailing,
Peter.

[GILow]

Originally Posted by peter57

Hi Gilow,

42 ft "tardis" I tried to buy the boat myself and she only played on the anchor wind against with the rest of us. The 43" S&S Huon Pine splined I use to own was also built by Ron Swanson 1961 she is in Gove at the moment.

Cheers,
Keep on Sailing,
Peter.

Ah lovely, that boat must have got around a bit because it is a name I have heard mentioned or read about a few times before. I would love to know what has become of her now.

[El Pinguino]

Originally Posted by GILow

Ah lovely, that boat must have got around a bit because it is a name I have heard mentioned or read about a few times before. I would love to know what has become of her now.

Back on Gallifrey last I heard...... she had a few sisterships...

[GILow]

Originally Posted by peter57

Hi Gilow,

42 ft "tardis" I tried to buy the boat myself and she only played on the anchor wind against with the rest of us. The 43" S&S Huon Pine splined I use to own was also built by Ron Swanson 1961 she is in Gove at the moment.

Cheers,
Keep on Sailing,
Peter.

Hell's bells! Just found THIS on the web. No date on the google link darn it, but it looks like it was listed on Grays Online at some stage. Sounds like it is in pretty poor condition.

[peter57]

Originally Posted by reed1v

I for one am glad of GPS. Some of the old excitement was no fun; dangerous as well. Up here in Maine, a gps/radar combi makes navigating in thick fog a cake walk. No longer having to outrace fog banks is a wonderful luxury.

Hi Reedy,

I did not truly mean fun excitement and I have a 12" plotter down below at the nav station and 7" at the helm but its automatic not to trust them when they are so bloody accurate.

Cheers,
Keep on Sailing,
Peter.

[GILow]

Originally Posted by El Pinguino

Back on Gallifrey last I heard...... she had a few sisterships...

Oh ha ha... I am ashamed to admit I went looking for Gallifrey on Google Maps.. But in my defence, I was mostly too chicken to watch Doctor Who when I was little.

Actually, I still am too chicken.

[peter57]

Originally Posted by GILow

Hell's bells! Just found THIS on the web. No date on the google link darn it, but it looks like it was listed on Grays Online at some stage. Sounds like it is in pretty poor condition.

I would guess that is her as the owner at the time "Vic" lived and moored the boat at Hardy"s Bay which is on the other side of the Hawksbury river from Church Point. Vic was 65 when I was relating to the Tardis and I was 35 but now I am 59 so I am sure Vic would not own her now.

Cheers,
Keep on Sailing ,
Peter.

[thomm225]

Originally Posted by Kenomac

Yeah you're right, what do I know about sailing in an anchorage? If you like, I can also show you before and after underwater pictures of what the anchor set and anchor chain patterns looked like before and after this windy morning. But then again... What do I know?

Shot this last season:

Wow, looks like you are in a nice protected anchorage. Good Job!

Winds may be 35-40 knots at the top of the mast but not at water level.

My anchorages here at Kiptopeke the first couple years I owned the boat, I'd get caught in onshore 30 knot winds after midnight and had to wait til morning hoping the anchor would hold. I'd be about 70 yards offshore and it would be really rough

[Jim Cate]

Originally Posted by Kenomac

The meter on our previous Hunter was way off, so since then I've always had at least one handheld meter on board to double check when I have doubts. Seems to work for us. But no, other than double or triple checking (this boat came with another handheld), it hasn't been done professionally if there even is such a thing.

Using a hand held at deck level to calibrate a masthead anemometer has some issues, especially in boats with very tall rigs, but I suppose that you know that.

And comparing one's masthead meter to a nearby coastal station which publishes speeds averaged over some minutes is kinda hard to do accurately unless you also have reliable averaging for your data. I think everyone who watches their wind speed instrument does some sort of mental averaging, but I suspect that it isn't very reliable... sure isn't for me!

It is all complicated by the turbulence found in low level air flow. If one turns off any smoothing function in a masthead instrument (so that it tries to read out instantaneous wind speed), you see that it varies rapidly and frequently, both in speed and direction. An identical instrument placed nearby would do so as well, and they likely would never agree, because the flow field is so mixed up. Now, to be able to actually read some sort of semi-stable value, instruments have built in some form of data smoothing. Some allow you to change the time constant... our old SH has three levels of damping plus raw data, and playing with those values is interesting. Other manufacturers undoubtedly have different time constants employed, and this means that comparing readings between boats anchored or sailing nearby is pretty inaccurate. Oh, and don't forget the effects of masthead movement! Rolling or pitching can add or subtract considerable from the apparent velocity experienced by the sensor.

There are now fancy instruments that actually take the latter errors out, and they would improve the data considerably. I believe that Dockhead has one and has reported favorably on it.

So, what to do? For me, I've tried to relate my reported wind speed against Beaufort type observations, and adjusted the calibration so that the instrument agrees with the pretty pictures and descriptions in Bowditch. And then the real meat of the process is to relate how my own boat behaves when the instrument reads "x" knots, and sail accordingly. I don't need to have truly accurate numbers (though as a scientist I'd sure like to have them!), What I need is repeatable numbers, so that from day to day, and in differing conditions I know what to do re sail plan, etc.

One final observation: I've owned several sets of Standard Horizon instruments. All of them came from the factory set to read well above the proper values... this was true for both wind speed and boat speed (something that is pretty easy to calibrate accurately). I've wondered if other brands are the same?

Jim

[MarkSF]

My Bristol 31.1 sails at anchor horribly (function of the tall bow), so I tried the Sailrite anchor riding sail. It does reduce the amplitude of the swing by maybe 2/3. I'm of the opionion that it just needs to be bigger, to reduce the amplitude even more.

Thinking of enlarging it next rainy spell we get, and I find myself looking for a sewing project.

[a64pilot]

Originally Posted by Jim Cate

Ken, how did you calibrate your anemometer? Not an easy thing to do IME.

Jim

I have been trying to figure out how, I do not think my ST 60 can be adjusted, I did adjust the heading part of it and it gets off a little every now and again, I think birds mess it up, but that is a theory.
Anyway I feel certain that my anemometer reads higher than actual wind speeds, I guess it doesn't really matter, but inaccurate gauges annoy me, I had rather not have one, than have one that reads incorrectly.

I do have a method to do airspeed calibrations in an aircraft, it amounts to flying Cardinal headings and comparing indicated airspeed with GPS ground speed, you can calibrate that way, I see no reason why it wouldn't work on a boat. All aircraft have installation errors.


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