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Old 14-10-2021, 11:31   #301
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Re: What boatspeed should I expect, as a percentage of True wind?

JMH2002:

Thanks for those links, I'll review them and see if I can get some more insight. I'll need to get an accurate handheld anemometer to help with the windspeed tuning.

I agree; having more information is certainly the way to get the optimum performance, and safer operation, of a boat. It was true on our last boat that most of the information i now want was not needed, as it was a bit of a slow mover. But, as you say, boats are faster now, and this one certainly doesn't compare to our last boat (a double ender!).

Thanks for your comments.
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Old 14-10-2021, 11:39   #302
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Re: What boatspeed should I expect, as a percentage of True wind?

Quote:
Originally Posted by Tupaia View Post
A cautionary note:

Assuming your code zero flies from the mast head you might need to be concerned or at least be aware of using it with a "reefed" main.

A headsail flying from the mast head on a fractional rig usually relies on the mainsail leach loads to counteract forces on the unsupported top part of the mast.

How is your top mast supported?
Running backstays?
Jumper stay?

Sailing looks good in the vids BTW.
Thanks Tupaia, for your comments.

The code zero, unfortunately, is at 1m above the forestay. There was apparently a mis-understanding between Selden, and myself, regards the height of the spinnaker halyard. I wanted it at 18m, on our 19.6m mast, but it turns out it's at 17m, along with the screecher halyard.

The mainsail, with the first reef installed, sits at 16 metres above the deck, so 1m below the code 0.

I have running backstays at 18m, which was done as requested, and I'll be installing another halyard at 18m for the spinnaker.

I like the idea of an ultrasonic sensor, but I think it would still be affected by the upwash.

Thanks for the compliment. Our videos are true to life, as we don't know how to edit, and probably wouldn't bother anyway.

Cheers.
Paul.
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Old 14-10-2021, 11:47   #303
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What boatspeed should I expect, as a percentage of True wind?

I was getting jealous of you guys with the wind speed and direction instrument on your masthead as it seems like a good tool to dial in the performance of your boats. Then we hit the bridge and knocked of our Windex. Cost us $28 for a new windex compared to nearly a boat buck for the instrument. I can live with the $28 loss but still jealous!
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Old 14-10-2021, 12:02   #304
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Re: What boatspeed should I expect, as a percentage of True wind?

Quote:
Originally Posted by GRIT View Post
I like the idea of an ultrasonic sensor, but I think it would still be affected by the upwash.
You'll see some discussion about the ultrasonic sensors as as other variants, and wireless too, in the links I posted earlier.

None of the options are trouble free unfortunately.

Jedi, who is an electronics engineer or something also discussed how he implemented dual sensors of various types on his Sundeer 64 and what type of switches to use in particular to isolate and protect. He was previous struck by lightening.

So there is a lot of reading there, and searching through more of @Dockhead's posts and threads might be worthwhile as he has brought up many of these issues over the last couple of years. Both windspeed and boatspeed, because of course it's interelated.

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Old 14-10-2021, 12:06   #305
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Re: What boatspeed should I expect, as a percentage of True wind?

Tanks JMH2002. I'm looking forward to getting some insight on the matter.

Cheers.
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Old 14-10-2021, 12:07   #306
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Re: What boatspeed should I expect, as a percentage of True wind?

Quote:
Originally Posted by smj View Post
I was getting jealous of you guys with the wind speed and direction instrument on your masthead as it seems like a good tool to dial in the performance of your boats. Then we hit the bridge and knocked of our Windex. Cost us $28 for a new windex compared to nearly a boat buck for the instrument. I can live with the $28 loss but still jealous!
It would be even nicer if it worked!

Cheers SMJ.
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Old 14-10-2021, 13:57   #307
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Re: What boatspeed should I expect, as a percentage of True wind?

Thank you for the link jmh2002 and GRIT for the info on your setup.

I'm facing the same decision of NAC3 vs H5000. One of the key features in my wind is TWS Response, allowing the auto pilot to bear away when the wind speed increases over a certain level (e.g. when flying the asym). How has that one worked in practice for you?

On wind instruments, the money B&G want for a longer piece of carbon is horrific. I might make something myself.
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Old 14-10-2021, 14:45   #308
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Re: What boatspeed should I expect, as a percentage of True wind?

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Originally Posted by JustMurph View Post
Thank you for the link jmh2002 and GRIT for the info on your setup.

I'm facing the same decision of NAC3 vs H5000. One of the key features in my wind is TWS Response, allowing the auto pilot to bear away when the wind speed increases over a certain level (e.g. when flying the asym). How has that one worked in practice for you?

On wind instruments, the money B&G want for a longer piece of carbon is horrific. I might make something myself.
That's why we went for the H5000 too. I've got it setup, but I've never witnessed it work. I'll have to set it up for a 2 knot gust and a 20 degree course change, and see if it works. I don't know if it would let me know about the change, or if it just does it, and goes back to the original course without letting me know. I have it set up for a 20 degree course change on a 10 knot gust, but that may not have happened yet...

I agree about the wand being terribly expensive, for what it is. I've got a 2x4 that'll work as well as the wand. I'll probably settle for something in the middle of those two options.

Cheers.
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Old 15-10-2021, 09:30   #309
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Re: What boatspeed should I expect, as a percentage of True wind?

Quote:
Originally Posted by smj View Post
I was getting jealous of you guys with the wind speed and direction instrument on your masthead as it seems like a good tool to dial in the performance of your boats. Then we hit the bridge and knocked of our Windex. Cost us $28 for a new windex compared to nearly a boat buck for the instrument. I can live with the $28 loss but still jealous!
Your installation would be even more expensive side than most, because you also need sensor to account for mast rotation.
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Old 16-10-2021, 18:41   #310
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Re: What boatspeed should I expect, as a percentage of True wind?

Quote:
Originally Posted by sailjumanji View Post
Your installation would be even more expensive side than most, because you also need sensor to account for mast rotation.


Your absolutely correct, and more of a reason to just replace the Windex that we own.
I would love to own a decent wind/speed indicator but realize that would probably go against our go simple motto.
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Old 27-10-2021, 15:42   #311
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Re: What boatspeed should I expect, as a percentage of True wind?

Not to further derail the 90deg tacking angle thread...

Quote:
Originally Posted by jmh2002 View Post
...take care to not have the same problem as fxykty, where the car(s) aren't sufficient for the real loads encountered.
On that subject, for reference here's the various Harken links regarding Traveller Systems and Load Calculations, as well as Block Deflections.

Maybe it's helpful.

Genoa Lead Q&A
https://www.harken.com/en/support/faq/genoa-lead-qa/

Genoa System Loading Calculator
https://www.harken.com/en/calculator...ng-calculator/

Mainsheet Traveler Systems Q&A
https://www.harken.com/en/support/fa...er-systems-qa/

Mainsheet Loading Calculator
https://www.harken.com/en/calculator...ng-calculator/

Block Loading vs. Angle of Deflection
https://www.harken.com/en/support/te...of-deflection/

Calculators (Index)
https://www.harken.com/en/support/se...s/calculators/

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Old 27-10-2021, 18:40   #312
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Re: What boatspeed should I expect, as a percentage of True wind?

Thanks JMH2002.

I'll take a look at those.

Cheers.
Paul.
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Old 27-10-2021, 21:14   #313
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Re: What boatspeed should I expect, as a percentage of True wind?

I missed a couple:

Traveler Track Q&A
https://www.harken.com/en/support/fa...eler-track-qa/

Curved Track
https://www.harken.com/en/support/te.../curved-track/
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Old 28-10-2021, 04:22   #314
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Re: What boatspeed should I expect, as a percentage of True wind?

Guarantee you the loads on a cat are higher than the Harken calculator would indicate. It’s based on typical monohull stability numbers…
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Old 28-10-2021, 10:34   #315
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Re: What boatspeed should I expect, as a percentage of True wind?

Agreed, they create a baseline to which you should add a factor for your particular boat.
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