[PUP] Any suggestion - or PPM should die

[John Marshall]

I think you missed the point of Dashew's discussion on speed... it has  
nothing to do with waiting for the right forecast and enjoying the  
passage. The atmosphere can simply change enough during a very long  
passage to render any initial forecast useless.

The weather crystal-ball reduces accuracy with lead time, and while a  
3 or 4 day forecast is pretty good, a 7 to 10 way one isn't so great.  
Not to mention the 20 to 30 days it will take a slow boat to make the  
longest passages. This isn't fixable with improved forecasting.

He's found that if you get the best possible daily weather updates  
underway, you can still get in situations where you can't avoid severe  
weather with a 7 or 8 knot boat, but at 11 to 12 knots, you can always  
get out of the way. Also, you have to have the excess range to make a  
huge detour. His conclusion comes from vast experience, given he's  
been passagemaking for something like 30 years.

That speed requirement is the single most difficult requirement of his  
designs. To have much greater range than the passage requires  
(something like 4000 miles at 11 or 12 knots, given the longest  
passages have a great-circle distance approaching 3000 miles) means a  
very long, skinny boat... you can't get efficient hull speeds like  
that on anything we could envision building. He wound up at 83 feet.

The alternative that sail boats have used to deal with this  
uncertainty is hoving-to when you are exhausted and using a parachute  
drogue or sea-anchor when conditions overwhelm you. No crew can keep  
going when the weather gets too bad. The first technique doesn't work  
for a power boat, but the second can, albeit with a lot of pre- 
planning and setup. But the issue of sea-anchors along would fill a  
book.

Anyway, while Dashew was prepared for the later, his design goal was  
to have a power passagemaker that took the entire issue out of  
consideration. That meant lots of speed.

John

On Dec 12, 2008, at 5:47 AM, Ross Anderson wrote:

> I'm sure there have been times when we all wish we could have outrun
> some weather but with the availability of good reports these days and
> a willingness to take it easy speed is not critical. To me the passage
> is as important as the goal. God Bless - Ross 10&2
>
> On Thu, Dec 11, 2008 at 1:19 AM, Peter Sheppard
> <Peter at petersheppard.com.au> wrote:
>> I agree with John Marshall that we should look at Steve Dashew's
>> "Windhorse" which has to be the only breakthrough in passagemakers  
>> that
>> I have heard of, and we should have a go at debating his  
>> innovations. I
>> cannot see anything on his boat that I don't admire when I put into
>> context of what he and his wife were trying to achieve.
>>
>> Waffling on about the good old days is just negative ramblings from  
>> some
>> old codger's trying to justify a time out there sailing with the bare
>> basics, when the guys with the spas on board these days were  
>> landlocked
>> and had their heads down and butts up scrounging for a dollar for  
>> their
>> dream retirement.
>>
>> A perfect passagemaker is a boat that will take you safely and
>> comfortably over a long distance, keeping the water on the outside,  
>> and
>> giving you a deep sense of satisfaction when you wrap up your lines  
>> at
>> the end.
>>
>> Question: What do people thing about Dashews need for speed on his  
>> FPB,
>> and is it worth it?
>>
>> Peter
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