Date   

Re: [Amel Yacht Owners] Grease for oil seals

 

Craig,

My answer was appropriate.

Best,

CW Bill Rouse
Admiral, Texas Navy
Commander Emeritus

Amel School  http://www.amelschool.com
720 Winnie St
Galveston Island, TX 77550

+1(832) 380-4970

Any opinions and conclusions expressed in this message are solely those of the author and should not be construed as representing the opinion of an expert. Manufacturers' and Expert's precautions must be considered when dealing with mechanical and/or electrical systems to ensure that you are NOT harmed, and/or the device and/or system is NOT ruined. If in doubt, do not touch any mechanical and/or electrical device or system referred to above.


On Thu, Sep 13, 2018 at 8:42 PM sangaris@... [amelyachtowners] <amelyachtowners@...> wrote:
 

Bill - believe that was Pat#123's question.



---In amelyachtowners@..., wrote :

Craig,

I suggest sticking with waterproof grease, unless you find out specifically what type of silicone grease Amel has been using lately in Martinique. There are many different kinds of silicone grease.

Best,

CW Bill Rouse
Admiral, Texas Navy
Commander Emeritus
Amel School www.amelschool.com
720 Winnie St
Galveston Island, TX 77550
+1(832) 380-4970

On Wed, Sep 12, 2018, 20:14 sailw32@... [amelyachtowners] <amelyachtowners@...> wrote:
 

I am going in install three new oils seals and a new wear bushing . I have for years been using wheel bearing grease,I have never had any leaks. However, I saw a mention of silicone grease being used. Would that be better ,is this what is supposed to be used?

Thanks,

Pat 

SM#123


MaxProp Zincs

greatketch@...
 

For those of you who have older SM's with MaxProps, and who use zincs on the prop...


Frequently you will hear complaints about either premature loss of the zinc, or having it come loose from two for the attachment bolts and spinning around--wildly out of balance.  This could happen in theory if the anode was simply a chunk of cast zinc, but this should never happen, if you get properly made anodes.  What is "proper"?  There is an internal non-zinc frame cast into the zinc that the bolts go through.  Basically, this secures the zinc until it is nearly all gone.


Here is a photo of a "proper" zinc anode at the very end of its useful life, and maybe a little past it, that clearly shows the internal frame.  This was a Martyr brand zinc. Even though rather eroded, it is still tightly secured against the metal face of the prop as it should be and doing its job.


Unfortunately, I know of no way to be sure ahead of time that the frame is actually there...  It is not magnetic, and is completely buried inside the casting when it is fresh.


Bill Kinney

SM160, Harmonie

Annapolis, MD, USA



Re: [Amel Yacht Owners] Hurricane

karkauai
 

Hi Alex,
Merci, mon ami.

I’ve been thinking about you too, as we discussed how best to proceed.  Fortunately it appears the storm is turning S away from us, but could have just as easily turned a bit N and charged right up the Chesapeake. 

We will get some rain and 20-30kt winds, at worst.  I hauled Kristy because dock isn’t adequate for more than 2 foot storm surge.  Her masts are already down for be painting.
Iris put her 95 y/o wooden catboat on a big mooring ball in a hurricane hole a few miles from StMichaels.  We should be fine.


Kent Robertson
S/V Kristy
USA cell: 828-234-6819

On Sep 13, 2018, at 6:38 AM, Alexandre Uster von Baar uster@... [amelyachtowners] <amelyachtowners@...> wrote:

 

Thinking of you Kent.

Sincerely, Alexandre

--------------------------------------------
On Thu, 9/13/18, Kent Robertson karkauai@... [amelyachtowners] <amelyachtowners@...> wrote:

Subject: Re: [Amel Yacht Owners] Hurricane
To: amelyachtowners@...
Date: Thursday, September 13, 2018, 2:50 AM


 









Thanks Danny,It looks like mostly rain in
St Michaels MD and the northern Chesapeake.The docks at the
boat yard Iin Cambridge are not adequate in anything more
than a 2-3 ft storm surge.    Kristy was due to be
hauled in two weeks, so I had her hauled yesterday instead.
 

This storm will
be devastating for  the eastern half of N and S Carolina.
 I hope others have all gotten out of her
way.

KentS/V Kristy
SM 243




Re: [Amel Yacht Owners] Hurricane

Mark Garver
 


We are down near Mobjack bay, up the Severn River and we had our boat hauled out yesterday to be on the safe side. We were hauling her in a couple of weeks anyway for a good bottom cleaning, so it all worked out. I hope everyone was able to get clear of Florence and the ones following.

Mark
SV It's Good
SM#105

On Sep 13, 2018, at 07:51 AM, "Patrick Mcaneny sailw32@... [amelyachtowners]" wrote:

 

Danny, The Chesapeake Bay will have little to no impact from the hurricane. Most damage will be limited to the N and S Carolina coastline and inland many miles. It is due to come ashore Friday, with tidal surge as high as 13 ft. on top of high tides and then large waves on top of that. We dodged that bullet, at my age I don't need the excitement . I feel for those in the way,the flooding will be bad. I guess you are in Alaska by now, enjoy your trip.

Thanks,
Pat
SM#123


-----Original Message-----
From: simms@... [amelyachtowners]
To: amelyachtowners
Sent: Wed, Sep 12, 2018 9:59 pm
Subject: [Amel Yacht Owners] Hurricane

 

Hi Pat and others in the line. 
How are all you guys situated with that hurricane coming in. Feel for you all. Wishing you all the best.
Danny
SM 299
Ocean Pearl

On 12/09/2018 04:24, "Patrick Mcaneny sailw32@... [amelyachtowners]" <amelyachtowners@...> wrote:
 
Rick, Sorry about your deal, but get out of there. If you have not seen the latest forecast, they are predicting it to turn SW , maybe going S along coast before turning inland . So that brings it closer to Charleston . Don't waste time replying , but let us know how you make out with the storm ,when you can.
Be Safe and Good Luck,
Pat
SM Shenanigans


-----Original Message-----
From: rickgrimes1@... [amelyachtowners] <amelyachtowners@...>
To: amelyachtowners <amelyachtowners@...>
Sent: Tue, Sep 11, 2018 10:29 pm
Subject: [Amel Yacht Owners] S/V Rascal

 



Hello Amel Friends,

With mixed feelings about selling, we recently asked you to identify anyone you knew who might be interested in buying Rascal.  Happily, we received a number of inquiries and had a contract soon thereafter. 

However, we couldn’t come to agreement on price and the buyer reneged.  So we are happy to keep sailing until a serious buyer comes along—perhaps referred to us by one of you.  Updated details about Rascal can be seen here.  

Rascal is berthed at the Charleston City Marina, SC though we are likely to leave tomorrow morning to flee the wrath of Hurricane Florence!

 

Rick and Linda Grimes

ASM2K #404

 

 











Re: [Amel Yacht Owners] Fwd: Seat photos in boat.

Danny and Yvonne SIMMS
 

Our stool swivelled and so does my seat. Thought they were all like that No trouble staying on and quite handy for socialising with the cook seated comfortably with wine in hand.
Cheers
Danny
SM
299
Ocean pearl
Danny


On 12/09/2018 18:21, "divanz620@... [amelyachtowners]" <amelyachtowners@...> wrote:
 

Ours doesn't, it is firmly locked in place.

I don;t think I want a swiveling nav seat.
Cheers
Alan
Elyse SM437
Noumea



Re: [Amel Yacht Owners] Hurricane

Danny and Yvonne SIMMS
 

Thanks Pat. Like you i feel for those in the path. We are in alaska having a ball.

To all amelians thst may be in the path. God be with you.

We pray for your safety.

Danny

SM 299

Ocean pearl

On 13 September 2018 at 23:50 "Patrick Mcaneny sailw32@... [amelyachtowners]" <amelyachtowners@...> wrote:

 

Danny, The Chesapeake Bay will have little to no impact from the hurricane. Most damage will be limited to the N and S Carolina coastline and inland many miles. It is due to come ashore Friday, with tidal surge as high as 13 ft. on top of high tides and then large waves on top of that. We dodged that bullet, at my age I don't need the excitement . I feel for those in the way,the flooding will be bad. I guess you are in Alaska by now, enjoy your trip.

Thanks,
Pat
SM#123


-----Original Message-----
From: simms@... [amelyachtowners] <amelyachtowners@...>
To: amelyachtowners <amelyachtowners@...>
Sent: Wed, Sep 12, 2018 9:59 pm
Subject: [Amel Yacht Owners] Hurricane

 
 
Hi Pat and others in the line. 
How are all you guys situated with that hurricane coming in. Feel for you all. Wishing you all the best.
Danny
SM 299
Ocean Pearl

On 12/09/2018 04:24, "Patrick Mcaneny sailw32@... [amelyachtowners]" < amelyachtowners@...> wrote:
 
Rick, Sorry about your deal, but get out of there. If you have not seen the latest forecast, they are predicting it to turn SW , maybe going S along coast before turning inland . So that brings it closer to Charleston . Don't waste time replying , but let us know how you make out with the storm ,when you can.
Be Safe and Good Luck,
Pat
SM Shenanigans


-----Original Message-----
From: rickgrimes1@... [amelyachtowners] < amelyachtowners@...>
To: amelyachtowners < amelyachtowners@...>
Sent: Tue, Sep 11, 2018 10:29 pm
Subject: [Amel Yacht Owners] S/V Rascal

 
 

 
Hello Amel Friends,
 
With mixed feelings about selling, we recently asked you to identify anyone you knew who might be interested in buying Rascal.  Happily, we received a number of inquiries and had a contract soon thereafter. 
 
However, we couldn’t come to agreement on price and the buyer reneged.  So we are happy to keep sailing until a serious buyer comes along—perhaps referred to us by one of you.  Updated details about Rascal can be seen here.  
 
Rascal is berthed at the Charleston City Marina, SC though we are likely to leave tomorrow morning to flee the wrath of Hurricane Florence!
 
 
 
Rick and Linda Grimes
 
ASM2K #404
 
 
 
 


 
 
 
 

 
 

 


 


 


Re: [Amel Yacht Owners] Grease for oil seals

Craig Briggs
 

Bill - believe that was Pat#123's question.


---In amelyachtowners@..., <brouse@...> wrote :

Craig,

I suggest sticking with waterproof grease, unless you find out specifically what type of silicone grease Amel has been using lately in Martinique. There are many different kinds of silicone grease.

Best,

CW Bill Rouse
Admiral, Texas Navy
Commander Emeritus
Amel School www.amelschool.com
720 Winnie St
Galveston Island, TX 77550
+1(832) 380-4970

On Wed, Sep 12, 2018, 20:14 sailw32@... [amelyachtowners] <amelyachtowners@...> wrote:
 

I am going in install three new oils seals and a new wear bushing . I have for years been using wheel bearing grease,I have never had any leaks. However, I saw a mention of silicone grease being used. Would that be better ,is this what is supposed to be used?

Thanks,

Pat 

SM#123


Re: [Amel Yacht Owners] Grease for oil seals

 

Craig,

I suggest sticking with waterproof grease, unless you find out specifically what type of silicone grease Amel has been using lately in Martinique. There are many different kinds of silicone grease.

Best,

CW Bill Rouse
Admiral, Texas Navy
Commander Emeritus
Amel School www.amelschool.com
720 Winnie St
Galveston Island, TX 77550
+1(832) 380-4970


On Wed, Sep 12, 2018, 20:14 sailw32@... [amelyachtowners] <amelyachtowners@...> wrote:
 

I am going in install three new oils seals and a new wear bushing . I have for years been using wheel bearing grease,I have never had any leaks. However, I saw a mention of silicone grease being used. Would that be better ,is this what is supposed to be used?

Thanks,

Pat 

SM#123


Re: [Amel Yacht Owners] Re: Predict Wind

Patrick McAneny
 

Alan, What you and Bill wrote has enlightened me in regards to PW ,and I now will look at it differently from when I purchased it. I will assume it should be viewed more as a suggestion of what to expect ,more than a prediction .
Thanks,
Pat
SM#123


-----Original Message-----
From: divanz620@... [amelyachtowners]
To: amelyachtowners
Sent: Thu, Sep 13, 2018 3:30 am
Subject: [Amel Yacht Owners] Re: Predict Wind

 
As Bill says, you have to remember that this data GFS PWG ECMWF PWE is all theoretical. Models are just that they are not forecasts....they are algorithm generated numerical models
A good forecaster looks at the models but makes assessments based on many other factors to provide a forecast.
GRIB files (which is what these are) can give you an "idea" of what might be happening in the near future.
In my experience even when they all agree, this data is only valid for about 3-4 days.
In the Pacific the models are notoriously inaccurate especially around land forms, isolated islands etc. 
Predict Wind claim that their enhanced models take this into account, but in my experience other than when there is a steady trade wind flow, they're not that accurate.
...The wind speeds are frequently underestimated by PWG and overestimated by PWE in my locale. About the only th ing you can almost depend on is the direction...but close to landforms that not always true either....We have seen PWE and PWG give completely different wind directions at the same time.
Even the top forecasters don;t always get it right.
BUT in terms of cyclones / hurricanes, as Bill says, the models just can't deal with those highly concentrated weather events.
One needs to look at all the available information, models, weather charts, forecasts ( from forecasters...not buoy weather etc) and try to decide what is most likely and make plans on that.
One of things that happens with all this scrutiny here in the S Pacific when heading S ahead of the cyclone season is what they call "Analysis Paralysis"...so much information and conflicting data that no-one does anything !
We look for what's mostly likely suitable weather and then go....you get what you get and you should be able to deal with it....hurricanes aside.....

Cheers
Alan
Elyse SM437
Noumea


Re: [Amel Yacht Owners] Hurricane

Patrick McAneny
 

Danny, The Chesapeake Bay will have little to no impact from the hurricane. Most damage will be limited to the N and S Carolina coastline and inland many miles. It is due to come ashore Friday, with tidal surge as high as 13 ft. on top of high tides and then large waves on top of that. We dodged that bullet, at my age I don't need the excitement . I feel for those in the way,the flooding will be bad. I guess you are in Alaska by now, enjoy your trip.
Thanks,
Pat
SM#123


-----Original Message-----
From: simms@... [amelyachtowners]
To: amelyachtowners
Sent: Wed, Sep 12, 2018 9:59 pm
Subject: [Amel Yacht Owners] Hurricane

 
Hi Pat and others in the line. 
How are all you guys situated with that hurricane coming in. Feel for you all. Wishing you all the best.
Danny
SM 299
Ocean Pearl

On 12/09/2018 04:24, "Patrick Mcaneny sailw32@... [amelyachtowners]" <amelyachtowners@...> wrote:
 
Rick, Sorry about your deal, but get out of there. If you have not seen the latest forecast, they are predicting it to turn SW , maybe going S along coast before turning inland . So that brings it closer to Charleston . Don't waste time replying , but let us know how you make out with the storm ,when you can.
Be Safe and Good Luck,
Pat
SM Shenanigans


-----Original Message-----
From: rickgrimes1@... [amelyachtowners] <amelyachtowners@...>
To: amelyachtowners <amelyachtowners@...>
Sent: Tue, Sep 11, 2018 10:29 pm
Subject: [Amel Yacht Owners] S/V Rascal

 

Hello Amel Friends,
With mixed feelings about selling, we recently asked you to identify anyone you knew who might be interested in buying Rascal.  Happily, we received a number of inquiries and had a contract soon thereafter. 
However, we couldn’t come to agreement on price and the buyer reneged.  So we are happy to keep sailing until a serious buyer comes along—perhaps referred to us by one of you.  Updated details about Rascal can be seen here.  
Rascal is berthed at the Charleston City Marina, SC though we are likely to leave tomorrow morning to flee the wrath of Hurricane Florence!
 
Rick and Linda Grimes
ASM2K #404
 
 




Re: [Amel Yacht Owners] Hurricane

Alexandre Uster von Baar
 

Thinking of you Kent.

Sincerely, Alexandre



--------------------------------------------

On Thu, 9/13/18, Kent Robertson karkauai@yahoo.com [amelyachtowners] <amelyachtowners@yahoogroups.com> wrote:

Subject: Re: [Amel Yacht Owners] Hurricane
To: amelyachtowners@yahoogroups.com
Date: Thursday, September 13, 2018, 2:50 AM


 









Thanks Danny,It looks like mostly rain in
St Michaels MD and the northern Chesapeake.The docks at the
boat yard Iin Cambridge are not adequate in anything more
than a 2-3 ft storm surge.    Kristy was due to be
hauled in two weeks, so I had her hauled yesterday instead.
 

This storm will
be devastating for  the eastern half of N and S Carolina.
 I hope others have all gotten out of her
way.

KentS/V Kristy
SM 243


Re: [Amel Yacht Owners] Hurricane

Alan Leslie
 

All the best Kent, I hope it goes well for you
Cheers
Alan
Elyse SM437


Re: [Amel Yacht Owners] Hurricane

karkauai
 

Thanks Danny,
It looks like mostly rain in St Michaels MD and the northern Chesapeake.The docks at the boat yard Iin Cambridge are not adequate in anything more than a 2-3 ft storm surge.    Kristy was due to be hauled in two weeks, so I had her hauled yesterday instead.  

This storm will be devastating for  the eastern half of N and S Carolina.  I hope others have all gotten out of her way.


Kent
S/V Kristy
SM 243


Re: Predict Wind

Alan Leslie
 

As Bill says, you have to remember that this data GFS PWG ECMWF PWE is all theoretical. Models are just that they are not forecasts....they are algorithm generated numerical models
A good forecaster looks at the models but makes assessments based on many other factors to provide a forecast.
GRIB files (which is what these are) can give you an "idea" of what might be happening in the near future.
In my experience even when they all agree, this data is only valid for about 3-4 days.
In the Pacific the models are notoriously inaccurate especially around land forms, isolated islands etc. 
Predict Wind claim that their enhanced models take this into account, but in my experience other than when there is a steady trade wind flow, they're not that accurate.
...The wind speeds are frequently underestimated by PWG and overestimated by PWE in my locale. About the only thing you can almost depend on is the direction...but close to landforms that not always true either....We have seen PWE and PWG give completely different wind directions at the same time.
Even the top forecasters don;t always get it right.
BUT in terms of cyclones / hurricanes, as Bill says, the models just can't deal with those highly concentrated weather events.
One needs to look at all the available information, models, weather charts, forecasts ( from forecasters...not buoy weather etc) and try to decide what is most likely and make plans on that.
One of things that happens with all this scrutiny here in the S Pacific when heading S ahead of the cyclone season is what they call "Analysis Paralysis"...so much information and conflicting data that no-one does anything !
We look for what's mostly likely suitable weather and then go....you get what you get and you should be able to deal with it....hurricanes aside.....

Cheers
Alan
Elyse SM437
Noumea


Re: [Amel Yacht Owners] Re: Predict Wind

Peter Forbes
 

This forum is just nothing short of very impressive for this sort of knowledge and comment. It makes me want to take Carango off the market and go sailing again.

Thank you.

Peter Forbes
Carango
Amel54#035
La Rochelle
00447836 209730

On 13 Sep 2018, at 01:01, Patrick Mcaneny sailw32@... [amelyachtowners] <amelyachtowners@...> wrote:

 

Bill , You should work for PW , you better explained the models and how the forecast are derived than their contact reps did. It still concerns me how inaccurately the winds are predicted. I will have to assume that all wind predictions may well be underestimated by a considerable degree.Thanks for your time to explain.

Pat 
SM#123


-----Original Message-----
From: greatketch@... [amelyachtowners] <amelyachtowners@...>
To: amelyachtowners <amelyachtowners@...>
Sent: Wed, Sep 12, 2018 7:11 pm
Subject: [Amel Yacht Owners] Re: Predict Wind

 
Pat,

PredictWind has four different models that it presents.  The first two are the GFS and ECMWF which are the two major worldwide weather models.  Nothing about these models is special to PredictWind, these are exactly the same two models that virtually EVERY weather forecast agency all over the world uses. ECMWF tends not to show in many "free" weather programs because you have to buy the results from the European Center for Mid-range Weather Forecasting.  The output from the GFS model is free to all from NOAA.

The other two models are the PWG and PWE are the PredictWind's "enhanced" versions of the output from the GFS and ECMWF models. I have not found them to be significantly more helpful than the actual model outputs.  I do not understand exactly what PW does to create this output from the major models.

In comparing model outputs to the & quot;real world" data, there are many things that can make them look different.  Starting with the fact that the most violent parts of a very large hurricane are actually a rather small weather feature on a global scale. 

PredictWind averages conditions over significant areas, and this can significantly impact the numbers.  In the highest resolution data available from PredictWind it still averages data over 50km.  That is a very large area when you are talking about a hurricane, where the highest winds are in a very narrow band around the eye.  To take this to an extreme example, PredictWind can not tell you about the wind speed in a tornado, it is too far small.  It's the same with a hurricane, although it obviously does better.

The GFS model itself only works internally to a resolution of 28km.  ECMWF model works at a higher resolution internally (9 or 10km, I think). So the models actually calculate a LOT more data than PredictWind presents, but they are still an approximation--at best--of what a real hurricane looks like.

Another issue is that it is not always clear about what wind number we are actually talking about.  Is the the 1 minute average?  the 3 minute average?  the surface wind?  The wind at 10 meter elevation?  All these numbers can be very different.  I don't know which of these numbers PredictWind presents.  I don't really care, for the way I use the program.  Many times the m edia presents the biggest number they can find because they sell more advertising that way.

I always caution people when they look at GRIB files created by computer programs. They look so PRECISE, it is so tempting to trust them.  They have none of the caveats that and weasel words that come from weather forecasters.  But these are NOT weather forecasts, and they are NOT reporting current conditions... they are the inputs that are used to create weather forecasts.  

Bill Kinney
SM160, Harmonie
Annapolis, MD, USA

---In amelyachtowners@..., wrote :

I bought Predict Wind a few months ago and  a Iridium G o to download offshore. I found it to under report winds with TS Gordon by a large margin,like 50%. Now with the Hurricane Florence and sustained winds of Cat4 140 mph reported for the last two days ,Predict Wind is showing from 68mph on PWG to 102 mph on GFS. Since this is a well reported storm I don't understand the under reported wind speed . Is PW generally this far off, can it be relied on? I asked PW about this and basically they said , that their models are"not geared to predicting hurricanes." I do not understand this explanation , a hurricane is simply a low pressure system, their models are not geared to predict low pressure systems ? I have been looking at their models and comparing them with known conditions. So far it is not reassuring , has it been found to be reliable ?
Thanks,
Pat
SM#123


Re: [Amel Yacht Owners] Fwd: Seat photos in boat.

Alan Leslie
 

Ours doesn't, it is firmly locked in place.
I don;t think I want a swiveling nav seat.
Cheers
Alan
Elyse SM437
Noumea


Re: [Amel Yacht Owners] Re: House Battery Balancing and Farewell for 2018

Alan Leslie
 

Yes that's when you have them all interconnected.
Our batteries aren't interconnected, we have a balancer for each set of 4 x 6V batteries.
Cheers
Alan
Elyse SM437
Noumea


Re: [Amel Yacht Owners] Re: Predict Wind

Patrick McAneny
 

Bill , You should work for PW , you better explained the models and how the forecast are derived than their contact reps did. It still concerns me how inaccurately the winds are predicted. I will have to assume that all wind predictions may well be underestimated by a considerable degree.Thanks for your time to explain.
Pat 
SM#123


-----Original Message-----
From: greatketch@... [amelyachtowners]
To: amelyachtowners
Sent: Wed, Sep 12, 2018 7:11 pm
Subject: [Amel Yacht Owners] Re: Predict Wind

 
Pat,

PredictWind has four different models that it presents.  The first two are the GFS and ECMWF which are the two major worldwide weather models.  Nothing about these models is special to PredictWind, these are exactly the same two models that virtually EVERY weather forecast agency all over the world uses. ECMWF tends not to show in many "free" weather programs because you have to buy the results from the European Center for Mid-range Weather Forecasting.  The output from the GFS model is free to all from NOAA.

The other two models are the PWG and PWE are the PredictWind's "enhanced" versions of the output from the GFS and ECMWF models. I have not found them to be significantly more helpful than the actual model outputs.  I do not understand exactly what PW does to create this output from the major models.

In comparing model outputs to the & quot;real world" data, there are many things that can make them look different.  Starting with the fact that the most violent parts of a very large hurricane are actually a rather small weather feature on a global scale. 

PredictWind averages conditions over significant areas, and this can significantly impact the numbers.  In the highest resolution data available from PredictWind it still averages data over 50km.  That is a very large area when you are talking about a hurricane, where the highest winds are in a very narrow band around the eye.  To take this to an extreme example, PredictWind can not tell you about the wind speed in a tornado, it is too far small.  It's the same with a hurricane, although it obviously does better.

The GFS model itself only works internally to a resolution of 28km.  ECMWF model works at a higher resolution internally (9 or 10km, I think). So the models actually calculate a LOT more data than PredictWind presents, but they are still an approximation--at best--of what a real hurricane looks like.

Another issue is that it is not always clear about what wind number we are actually talking about.  Is the the 1 minute average?  the 3 minute average?  the surface wind?  The wind at 10 meter elevation?  All these numbers can be very different.  I don't know which of these numbers PredictWind presents.  I don't really care, for the way I use the program.  Many times the m edia presents the biggest number they can find because they sell more advertising that way.

I always caution people when they look at GRIB files created by computer programs. They look so PRECISE, it is so tempting to trust them.  They have none of the caveats that and weasel words that come from weather forecasters.  But these are NOT weather forecasts, and they are NOT reporting current conditions... they are the inputs that are used to create weather forecasts.  

Bill Kinney
SM160, Harmonie
Annapolis, MD, USA

---In amelyachtowners@..., wrote :

I bought Predict Wind a few months ago and  a Iridium G o to download offshore. I found it to under report winds with TS Gordon by a large margin,like 50%. Now with the Hurricane Florence and sustained winds of Cat4 140 mph reported for the last two days ,Predict Wind is showing from 68mph on PWG to 102 mph on GFS. Since this is a well reported storm I don't understand the under reported wind speed . Is PW generally this far off, can it be relied on? I asked PW about this and basically they said , that their models are"not geared to predicting hurricanes." I do not understand this explanation , a hurricane is simply a low pressure system, their models are not geared to predict low pressure systems ? I have been looking at their models and comparing them with known conditions. So far it is not reassuring , has it been found to be reliable ?
Thanks,
Pat
SM#123


Re: Predict Wind

greatketch@...
 

Pat,

PredictWind has four different models that it presents.  The first two are the GFS and ECMWF which are the two major worldwide weather models.  Nothing about these models is special to PredictWind, these are exactly the same two models that virtually EVERY weather forecast agency all over the world uses. ECMWF tends not to show in many "free" weather programs because you have to buy the results from the European Center for Mid-range Weather Forecasting.  The output from the GFS model is free to all from NOAA.

The other two models are the PWG and PWE are the PredictWind's "enhanced" versions of the output from the GFS and ECMWF models. I have not found them to be significantly more helpful than the actual model outputs.  I do not understand exactly what PW does to create this output from the major models.

In comparing model outputs to the "real world" data, there are many things that can make them look different.  Starting with the fact that the most violent parts of a very large hurricane are actually a rather small weather feature on a global scale. 

PredictWind averages conditions over significant areas, and this can significantly impact the numbers.  In the highest resolution data available from PredictWind it still averages data over 50km.  That is a very large area when you are talking about a hurricane, where the highest winds are in a very narrow band around the eye.  To take this to an extreme example, PredictWind can not tell you about the wind speed in a tornado, it is too far small.  It's the same with a hurricane, although it obviously does better.

The GFS model itself only works internally to a resolution of 28km.  ECMWF model works at a higher resolution internally (9 or 10km, I think). So the models actually calculate a LOT more data than PredictWind presents, but they are still an approximation--at best--of what a real hurricane looks like.

Another issue is that it is not always clear about what wind number we are actually talking about.  Is the the 1 minute average?  the 3 minute average?  the surface wind?  The wind at 10 meter elevation?  All these numbers can be very different.  I don't know which of these numbers PredictWind presents.  I don't really care, for the way I use the program.  Many times the media presents the biggest number they can find because they sell more advertising that way.

I always caution people when they look at GRIB files created by computer programs. They look so PRECISE, it is so tempting to trust them.  They have none of the caveats that and weasel words that come from weather forecasters.  But these are NOT weather forecasts, and they are NOT reporting current conditions... they are the inputs that are used to create weather forecasts.  

Bill Kinney
SM160, Harmonie
Annapolis, MD, USA

---In amelyachtowners@..., <sailw32@...> wrote :

I bought Predict Wind a few months ago and  a Iridium Go to download offshore. I found it to under report winds with TS Gordon by a large margin,like 50%. Now with the Hurricane Florence and sustained winds of Cat4 140 mph reported for the last two days ,Predict Wind is showing from 68mph on PWG to 102 mph on GFS. Since this is a well reported storm I don't understand the under reported wind speed . Is PW generally this far off, can it be relied on? I asked PW about this and basically they said , that their models are"not geared to predicting hurricanes." I do not understand this explanation , a hurricane is simply a low pressure system, their models are not geared to predict low pressure systems ? I have been looking at their models and comparing them with known conditions. So far it is not reassuring , has it been found to be reliable ?

Thanks,

Pat

SM#123


Re: [Amel Yacht Owners] Predict Wind

karkauai
 

I’ve found winds to be higher than expected a couple of times, Pat...like 10 it’s stronger. But PassageWeather.com also under-estimated them.

Kent
S/V Kristy
SM243

On Sep 12, 2018, at 6:15 PM, sailw32@... [amelyachtowners] <amelyachtowners@...> wrote:

 

I bought Predict Wind a few months ago and  a Iridium Go to download offshore. I found it to under report winds with TS Gordon by a large margin,like 50%. Now with the Hurricane Florence and sustained winds of Cat4 140 mph reported for the last two days ,Predict Wind is showing from 68mph on PWG to 102 mph on GFS. Since this is a well reported storm I don't understand the under reported wind speed . Is PW generally this far off, can it be relied on? I asked PW about this and basically they said , that their models are"not geared to predicting hurricanes." I do not understand this explanation , a hurricane is simply a low pressure system, their models are not geared to predict low pressure systems ? I have been looking at their models and comparing them with known conditions. So far it is not reassuring , has it been found to be reliable ?

Thanks,

Pat

SM#123

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