Mountain wave

[Michael 182]

Hit a mountain wave today near Pikes Peak at FL190 in my TR-182. First I
couldn't maintain FL190 (I only have 300-400 fpm climb at that altitude
anyway) as my indicated airspeed descended to 80 K. Called ATC, got a block
altitude, FL 180 - 200. About a minute later I needed the upside. Shot to
over 2000 fpm climb (VSI was pegged) and with the nose pointed way down
leveled off at FL 195 and ground speed of 190 knots. Fun stuff.

Michael

[Marco Leon]

I had a similar encounter over the Adirondacks transitting Vermont. My VSI
started indicating a 100-200 ft/min descent and I subsequently pulled up.
Soon I found myself with full power, 80 kts indicated and a sorry-looking
groundspeed. ATC asked about my indicated airspeed and I asked for lower.
Once cleared, (you guessed it) I hit the other side of the wave and my
airspeed went into the yellow arc while maintaining level flight--forcing me
to reduce power. All this in a Warrior at about 6000 feet MSL.

Asked a couple of people about this and the ones who experienced it all
agreed it was freaky at first and all of our initial reactions were to scan
the panel for a problem.

Marco

"Michael 182" > wrote in message
news:Bwq0d.166098$Fg5.68105@attbi_s53...
> Hit a mountain wave today near Pikes Peak at FL190 in my TR-182. First I
> couldn't maintain FL190 (I only have 300-400 fpm climb at that altitude
> anyway) as my indicated airspeed descended to 80 K. Called ATC, got a
> block altitude, FL 180 - 200. About a minute later I needed the upside.
> Shot to over 2000 fpm climb (VSI was pegged) and with the nose pointed
> way down leveled off at FL 195 and ground speed of 190 knots. Fun stuff.
>
> Michael
>
>
>

[Scott D.]

Hmm. What time today were you overflying the peak. My in-laws are in
town and we took them up there around 1400 this afternoon. That was
about the time the snow and freezing rain hit with a lot of high
winds.

Just as a side note, I was out flying around 1100 this morning at COS
and even tho it was calm on the ground, we got up 1000' agl and with
all the virga around, it got real bumpy even at that low an altitude

Scott D.


On Fri, 10 Sep 2004 23:11:34 GMT, "Michael 182"
> wrote:

>Hit a mountain wave today near Pikes Peak at FL190 in my TR-182. First I
>couldn't maintain FL190 (I only have 300-400 fpm climb at that altitude
>anyway) as my indicated airspeed descended to 80 K. Called ATC, got a block
>altitude, FL 180 - 200. About a minute later I needed the upside. Shot to
>over 2000 fpm climb (VSI was pegged) and with the nose pointed way down
>leveled off at FL 195 and ground speed of 190 knots. Fun stuff.
>
>Michael
>
>

[jharper aaatttt cisco dddooottt com]

Wait til you hit a rotor. That's REAL fun. My one and only
experience had me lose about 2000' in maybe 10 seconds. People
told me that was impossible, but then they weren't there.
We were negative G for that time.

John

Michael 182 wrote:
> Hit a mountain wave today near Pikes Peak at FL190 in my TR-182. First I
> couldn't maintain FL190 (I only have 300-400 fpm climb at that altitude
> anyway) as my indicated airspeed descended to 80 K. Called ATC, got a block
> altitude, FL 180 - 200. About a minute later I needed the upside. Shot to
> over 2000 fpm climb (VSI was pegged) and with the nose pointed way down
> leveled off at FL 195 and ground speed of 190 knots. Fun stuff.
>
> Michael
>
>
>

[Mike Rapoport]

I don't understand. You generally don't get mountain wave and virga at the
same time. One requires stable air and the other generally occurs in
unstable air.

Mike
MU-2

<Scott D.> wrote in message
...
> Hmm. What time today were you overflying the peak. My in-laws are in
> town and we took them up there around 1400 this afternoon. That was
> about the time the snow and freezing rain hit with a lot of high
> winds.
>
> Just as a side note, I was out flying around 1100 this morning at COS
> and even tho it was calm on the ground, we got up 1000' agl and with
> all the virga around, it got real bumpy even at that low an altitude
>
> Scott D.
>
>
> On Fri, 10 Sep 2004 23:11:34 GMT, "Michael 182"
> > wrote:
>
>>Hit a mountain wave today near Pikes Peak at FL190 in my TR-182. First I
>>couldn't maintain FL190 (I only have 300-400 fpm climb at that altitude
>>anyway) as my indicated airspeed descended to 80 K. Called ATC, got a
>>block
>>altitude, FL 180 - 200. About a minute later I needed the upside. Shot to
>>over 2000 fpm climb (VSI was pegged) and with the nose pointed way down
>>leveled off at FL 195 and ground speed of 190 knots. Fun stuff.
>>
>>Michael
>>
>>
>

[Michael 182]

I was a little west of the Peak at about 2:00pm mountain yesterday. There
were wave clouds evident all over at FL 190, none of which you would have
seen from below the deck.

Michael



<Scott D.> wrote in message
...
> Hmm. What time today were you overflying the peak. My in-laws are in
> town and we took them up there around 1400 this afternoon. That was
> about the time the snow and freezing rain hit with a lot of high
> winds.
>
> Just as a side note, I was out flying around 1100 this morning at COS
> and even tho it was calm on the ground, we got up 1000' agl and with
> all the virga around, it got real bumpy even at that low an altitude
>
> Scott D.
>
>
> On Fri, 10 Sep 2004 23:11:34 GMT, "Michael 182"
> > wrote:
>
>>Hit a mountain wave today near Pikes Peak at FL190 in my TR-182. First I
>>couldn't maintain FL190 (I only have 300-400 fpm climb at that altitude
>>anyway) as my indicated airspeed descended to 80 K. Called ATC, got a
>>block
>>altitude, FL 180 - 200. About a minute later I needed the upside. Shot to
>>over 2000 fpm climb (VSI was pegged) and with the nose pointed way down
>>leveled off at FL 195 and ground speed of 190 knots. Fun stuff.
>>
>>Michael
>>
>>
>

[Michael 182]

He saw the virga at 11:00 am. The waves were evident at 2:00 pm. Evidently
the winds hit the front range in the afternoon.

Michael

"Mike Rapoport" > wrote in message
k.net...
>I don't understand. You generally don't get mountain wave and virga at the
>same time. One requires stable air and the other generally occurs in
>unstable air.
>
> Mike
> MU-2
>
> <Scott D.> wrote in message
> ...
>> Hmm. What time today were you overflying the peak. My in-laws are in
>> town and we took them up there around 1400 this afternoon. That was
>> about the time the snow and freezing rain hit with a lot of high
>> winds.
>>
>> Just as a side note, I was out flying around 1100 this morning at COS
>> and even tho it was calm on the ground, we got up 1000' agl and with
>> all the virga around, it got real bumpy even at that low an altitude
>>
>> Scott D.
>>
>>
>> On Fri, 10 Sep 2004 23:11:34 GMT, "Michael 182"
>> > wrote:
>>
>>>Hit a mountain wave today near Pikes Peak at FL190 in my TR-182. First I
>>>couldn't maintain FL190 (I only have 300-400 fpm climb at that altitude
>>>anyway) as my indicated airspeed descended to 80 K. Called ATC, got a
>>>block
>>>altitude, FL 180 - 200. About a minute later I needed the upside. Shot to
>>>over 2000 fpm climb (VSI was pegged) and with the nose pointed way down
>>>leveled off at FL 195 and ground speed of 190 knots. Fun stuff.
>>>
>>>Michael
>>>
>>>
>>
>
>

[Thomas Borchert]

Michael,

> Fun stuff.
>

Now imagine doing that in a glider and getting up to FL300. Did that in
the Lake Tahoe area once. Wow!

--
Thomas Borchert (EDDH)

[Larry Dighera]

On Mon, 13 Sep 2004 11:03:24 -0400, Todd Pattist
> wrote in
>::

>BTW, pilots, particularly in airplanes, should be really
>careful about slowing down and trying to outclimb a mountain
>wave. The preferred response is to put the nose down and go
>fast (assuming you can get a clearance for a lower alt if
>you're not VFR). It's often impossible to climb faster than
>the sinking air. Slowing down just gives teh air longer to
>try to shove you down into those granite bumpy things below
>that are causing the wave. The best response is usually to
>get through the down cycle of the wave as quickly as you
>can. It's also the most efficient response, particuarly when
>coupled with slowing during the up part of the wave.

Right. That's what glider guiders do: slow in rising air, and dive
through downdrafts.

But when I discussed this with a CFII, he said, "what goes up, comes
down." His advise was to hold a constant airspeed while flying VFR
through wave activity, and permit altitude excursions to occur. In
the end it should all balance out, and the pilot should find himself
at approximately the same altitude at which he entered the wave
activity upon exiting it.

[Stefan]

Larry Dighera wrote:

> But when I discussed this with a CFII, he said, "what goes up, comes
> down." His advise was to hold a constant airspeed while flying VFR
> through wave activity, and permit altitude excursions to occur.

As a glider pilot, I've never understood this hold-the-altitude-itis of
my motorised brethren. Deliberately wasting this huge amount of energy
which mother nature offers for free!

Stefan

[Michael 182]

"Thomas Borchert" > wrote in message
...
> Michael,
>
>> Fun stuff.
>>
>
> Now imagine doing that in a glider and getting up to FL300. Did that in
> the Lake Tahoe area once. Wow!
>
> --
> Thomas Borchert (EDDH)

Must have been pretty cold up there in a glider.
>

[Stefan]

Michael 182 wrote:

> Must have been pretty cold up there in a glider.

There's no such thing as cold weather, there's only insufficient
clothing. Here's how it looks up there in a glider:

http://www.glidingbasel.ch/fotos_berichte/DiverseSegelflugfotos/images/05.jpg
http://www.glidingbasel.ch/fotos_berichte/DiverseSegelflugfotos/images/06.jpg

Stefan

[Larry Dighera]

On Mon, 13 Sep 2004 18:35:47 +0200, Stefan >
wrote in >::

>As a glider pilot, I've never understood this hold-the-altitude-itis of
>my motorised brethren.

The desire of pilots of motorized aircraft to hold an altitude is a
result of FAR § 91.159 VFR cruising altitude or flight level.

http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=d7df614acd2723566f23cc2cf44f023e&rgn=div8&view=text&node=14:2.0.1.3.10.2.5.33&idno=14

[Stefan]

Larry Dighera wrote:

>> As a glider pilot, I've never understood this hold-the-altitude-itis of
>> my motorised brethren.

> The desire of pilots of motorized aircraft to hold an altitude is a
> result of FAR § 91.159 VFR cruising altitude or flight level.

And as a simple human being I'll never understand those people who can't
grasp irony unless it comes with a smiley.

Stefan

[Larry Dighera]

On Mon, 13 Sep 2004 14:11:26 -0400, Todd Pattist
> wrote in
>::

>Larry Dighera > wrote:
>
>>That's what glider guiders do: slow in rising air, and dive
>>through downdrafts.
>>
>>But when I discussed this with a CFII, he said, "what goes up, comes
>>down." His advice was to hold a constant airspeed while flying VFR
>>through wave activity, and permit altitude excursions to occur. In
>>the end it should all balance out, and the pilot should find himself
>>at approximately the same altitude at which he entered the wave
>>activity upon exiting it.
>
>That's a reasonable approach, but it has some disadvantages.
>
>First, you need to be sure you can get through the sinking
>air before terrain clearance becomes a problem. Faster in
>the sink means less altitude lost and more clearance over
>bad terrain.

Agreed. But the technique of diving through sinking air works better
with aircraft that possess low parasitic drag than it does with
"dirty" spam cans. Parasitic drag increases with the square of the
velocity doesn't it?

>Second, it's not as efficient.

Right. To the extent that the pilot fails to take advantage of the
rising air, the technique suggested by the CFII does fail to exploit
the energy inherent in rising air.

>There is free altitude available here - why not use it, particularly
>in the mountains where you may already be near the service ceiling.

If the mission calls for remaining near a specific cruising altitude,
pulling-up in lift zones and diving through sink zones will amplify
the altitude excursions beyond what would be encountered if constant
pitch attitude were maintained.

If the cruising altitude is within 3,000 AGL, a specific cruising
altitude need not be maintained (by regulation), and the 'dolphin'
technique would indeed provide a viable option for extracting energy
inherent in updrafts.

[Dylan Smith]

In article <Bwq0d.166098$Fg5.68105@attbi_s53>, Michael 182 wrote:
> Hit a mountain wave today near Pikes Peak at FL190 in my TR-182. First I
> couldn't maintain FL190 (I only have 300-400 fpm climb at that altitude
> anyway) as my indicated airspeed descended to 80 K.

Speed up in sink, slow down in lift is the general rule (OK, you
probably don't want to slow down in lift if you're on an ifr flight plan
- but if you speed up in the sink, or at least maintain your cruise
speed rather than slowing to 80 kts you'll lose less altitude.

Used this sort of thing to good effect in my C140 which was decidedly
lacking in power when crossing the mounains in the western US.

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"

[dancingstar]

Wow ! I Just found me a new background image !

Thanks,

Antonio

Stefan wrote:
> Michael 182 wrote:
>
>> Must have been pretty cold up there in a glider.
>
>
> There's no such thing as cold weather, there's only insufficient
> clothing. Here's how it looks up there in a glider:
>
> http://www.glidingbasel.ch/fotos_berichte/DiverseSegelflugfotos/images/05.jpg
>
> http://www.glidingbasel.ch/fotos_berichte/DiverseSegelflugfotos/images/06.jpg
>
>
> Stefan
>

[Cub Driver]

On Mon, 13 Sep 2004 11:03:24 -0400, Todd Pattist
> wrote:

>I went to FL300 in my glider over Mt. Washington once. It's
>quite fun to gain 25,000' of altitude without an engine :-)

Todd, I've heard about the "box" over Mt. Washington. (I assume you
weren't busting Class A when you did that?)

How big is the box, and how many days a year is it in effect?

Thanks!


all the best -- Dan Ford
email: (put Cubdriver in subject line)

The Warbird's Forum www.warbirdforum.com
Expedition sailboat charters www.expeditionsail.com

[Thomas Borchert]

Michael,

> st have been pretty cold up there in a glider.
>

You bet! If you want, I'll e-mail a photo of the panel showing minus 40
degrees centigrade - and of me in a thermo suit with moon boots. It's
not that bad where the sun shines on you through that big canopy, but
my feet were nearly frozen after two hours of flying. Some people who
do this regularly have electric thermopads in their boots.

--
Thomas Borchert (EDDH)

[Adam Aulick]

Stefan > wrote in message >...




> There's no such thing as cold weather, there's only insufficient
> clothing. Here's how it looks up there in a glider:
>
> http://www.glidingbasel.ch/fotos_berichte/DiverseSegelflugfotos/images/05.jpg

What is the black object that appears to be pasted to the outside of
the canopy in this image? Some kind of relative wind indicator?

[Peter Duniho]

"Adam Aulick" > wrote in message
om...
> What is the black object that appears to be pasted to the outside of
> the canopy in this image? Some kind of relative wind indicator?

Yes. "Yaw string".

[Michael 182]

About 30 years ago, when I was too young to know better, I went skiing in
temps of about 30 below. Now, at 51, there is nothing in the world that
could get me to go out in that weather - even gliding at FL300, as wonderful
as that seems.

Michael


"Thomas Borchert" > wrote in message
...
> Michael,
>
>> st have been pretty cold up there in a glider.
>>
>
> You bet! If you want, I'll e-mail a photo of the panel showing minus 40
> degrees centigrade - and of me in a thermo suit with moon boots. It's
> not that bad where the sun shines on you through that big canopy, but
> my feet were nearly frozen after two hours of flying. Some people who
> do this regularly have electric thermopads in their boots.
>
> --
> Thomas Borchert (EDDH)
>

[Stefan]

Adam Aulick wrote:

> What is the black object that appears to be pasted to the outside of
> the canopy in this image? Some kind of relative wind indicator?

Yes. A simple woolen string. It's the main instrument of a glider pilot.
You may ask why a string and not the ball? First, the string is *way*
more exact than the ball and second, it's a HUD (head up display).

Stefan

[Cub Driver]

On Tue, 14 Sep 2004 08:56:17 -0400, Todd Pattist
> wrote:

>IIRC, it's about 3x5 miles across.

Oh gosh, I'd assumed it was something that extended across New
Hampshire and maybe into Vermont and Maine!

If it's that small, it really is a box!

Did this box exist before GPS? Can you really locate yourself so
precisely at 20,000+ feet?

all the best -- Dan Ford
email: (put Cubdriver in subject line)

The Warbird's Forum www.warbirdforum.com
Expedition sailboat charters www.expeditionsail.com

[Dylan Smith]

In article >, Todd Pattist wrote:
> It's quieter than flying has any right to be, and I can fly
> by trimming my ship and then leaning to the sides or
> front/back even though my cockpit only allows a few inches
> of motion.

Now you'll probably laugh at me for this, but bear in mind you have an
enormous country to fly your glider in - mine is only 30nm by 15nm, and
our thermal conditions are so weak, last week I spent my entire flight
soaring at between 700 and 900 ft. AGL. The definition of a 'booming
day' is when we find 2-3 knots up and a 3000' cloud base. Such is island life.
This is why none of us fly glass - it's not worth it. A Ka-8 is a far
better glider here than a DG-505.

Earlier this year, we had a really booming day. I managed to get to
5,300 ft (which is a thermal soaring record here! - only to broken 2
hours later by someone who managed 5,500). The thermal activity was
fairly localised to the east coast. Since I was also the only tow pilot
for the day, and some people wanted towing (we also have a winch), I
regretfully had to go home. However, first, I decided I'd use all this
altitude well.

So I pointed the nose at the west coast, and was soon in still air. For
the next half hour or so, I was in no-lift air. I slowed the glider to
min sink (it's a Ka-8, so that's about walking pace), trimmed it and let
go of the controls. It was like a magic carpet ride. I slowly drifted
over the top of the mountain, and went all the way to the west coast,
then turned north towards the glider club. It's probably the most fun
glider flight I've had - just half an hour of almost silent and totally
effortless flight. It made a big change from my normal desperate
struggle to stay in feeble low level lift :-)

We do get wave from time to time, but it never seems to be where we can
take advantage of it :/

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"

[Stefan]

Dylan Smith wrote:

> Now you'll probably laugh at me for this,

On the contrary! Everybody can fly in booming conditions, but weak
thermals and low cloud base will sift the chaff from the wheat.

Stefan

[Maule Driver]

"Stefan" > wrote in message
...
> Dylan Smith wrote:
> > Now you'll probably laugh at me for this,
>
> On the contrary! Everybody can fly in booming conditions, but weak
> thermals and low cloud base will sift the chaff from the wheat.
>
I wonder if Mr. Smith's island flying is actually tough flying. Ironically,
soaring conditions can be 'weak' with low cloudbases but amazingly
consistent and 'easy' to stay aloft. You just don't go anywhere.... but you
see a few things clearly and often.

Anyway, just reflecting on South Florida conditions where low, closely
spaced, consistently popping thermals can be common.

[Maule Driver]

Sun helps.

"Stefan" > wrote in message
...
> Michael 182 wrote:
>
> > Must have been pretty cold up there in a glider.
>
> There's no such thing as cold weather, there's only insufficient
> clothing. Here's how it looks up there in a glider:
>
>
http://www.glidingbasel.ch/fotos_berichte/DiverseSegelflugfotos/images/05.jp
g
>
http://www.glidingbasel.ch/fotos_berichte/DiverseSegelflugfotos/images/06.jp
g
>
> Stefan
>

[Dylan Smith]

In article >, Maule Driver
wrote:
> I wonder if Mr. Smith's island flying is actually tough flying. Ironically,
> soaring conditions can be 'weak' with low cloudbases but amazingly
> consistent and 'easy' to stay aloft.

Unfortunately, it's not normally like that. We do get some days where
it's about as difficult to stay up as falling off a log, but most the
time the conditions are at best 'scratchy' and it's not unusual to start
going somewhere and suddenly find all the lift's gone when you're just
about out of gliding range from the airfield and have a desperate time
getting back.

The most notable incident was when someone had to 'ridge soar' off some
60 ft cliffs to get back to the airfield after the thermals decided to
abandon him some miles from the airfield...

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"

[Stefan]

Thinking at it ... those 5000 ft you mentioned in an earlier post
should have been enough to reach Scotland ... your once in a decade
chance to aquire silver distance! Nobody tried?

Stefan

[Dylan Smith]

In article >, Stefan wrote:
> Thinking at it ... those 5000 ft you mentioned in an earlier post
> should have been enough to reach Scotland ... your once in a decade
> chance to aquire silver distance! Nobody tried?

Trouble is we have to know in advance. We're not part of the UK and we
need to inform Customs if we're going there! Unless you're flying to a
large airfield you need to give them 24 hrs notice.

It is actually possible to just about squeak out the Silver distance
here by going right to the Point of Ayre and down to Chicken Rock. We
have discussed the possibility of doing this. The main problem is
getting either a very high cloudbase to climb up and do it all as a
'final glide' or consistent conditions across the island (we have a very
varied microclimate - it can be socked in so bad all day at Ronaldsway
that the airliners aren't moving, and we can be soaring in reasonable
thermals in the north only 30nm away). On the day we got all that
altitude, the 'booming conditions' were in a region only a few miles
square (although I think that day I could have glided up to the Point of
Ayre, back to Maughold, where it was working, climbed back up to 5,300,
then gone to Chicken Rock and then land at Ronaldsway). We do need to do
a little preparation for this such as make sure the grass areas at
Ronaldsway airport are landable because I don't think they'll want us on
their runways because they have quite a bit of airline traffic.

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"

[Cub Driver]

Thanks for the additional information, Todd. Newsgroups are wonderful
(especially if there's no election going on). -- Dan

On Wed, 15 Sep 2004 10:26:14 -0400, Todd Pattist
> wrote:

>Cub Driver > wrote:
>
>>>IIRC, it's about 3x5 miles across.
>>
>>Oh gosh, I'd assumed it was something that extended across New
>>Hampshire and maybe into Vermont and Maine!
>
>OK, you got me wondering, so I looked it up. It's about
>20nm x 13 nm - only off by a factor of four in length and 16
>in area :-) I knew I shouldn't have tried to remember.
>Mt. Washington is on the western upwind edge and the
>downwind corners are about 13 nm diagonally SSE and NNE
>
>>Did this box exist before GPS?
>
>Yes.
>
>>Can you really locate yourself so
>>precisely at 20,000+ feet?
>
>It's easier with GPS, but it's not too hard if you get
>familiar with the box corners.
>
>Once established in a wave, it feels like you're parked in
>3-space, so there's lots of time to get oriented and get
>into the right position before vertically entering Class A.
>It's quieter than flying has any right to be, and I can fly
>by trimming my ship and then leaning to the sides or
>front/back even though my cockpit only allows a few inches
>of motion. The altimeter is rolling up, but ground speed is
>near zero. You are sitting in majestic silence, high and
>mighty above a mountain landscape of ice, snow, rock and
>cloud. It brings a smile to my face to recall.
>
>"It is possible to fly without motors, but not without knowledge and skill."
>Wilbur Wright

all the best -- Dan Ford
email: (put Cubdriver in subject line)

The Warbird's Forum www.warbirdforum.com
Expedition sailboat charters www.expeditionsail.com

[Cub Driver]

On Thu, 16 Sep 2004 09:20:14 -0000, Dylan Smith
> wrote:

>Trouble is we have to know in advance. We're not part of the UK and we
>need to inform Customs if we're going there!

Surely the Brits wouldn't torture you or anything? I mean, everyone
knows that a glider doesn't have an engine, so has to go where the
wind blows, just like a balloon.

If things got tough, couldn't you try the Corrigan Defense? "I was
trying to fly to Sweden but my compass was wrong."

Well, I suppose they could make you pay VAT on your illegal import....

all the best -- Dan Ford
email: (put Cubdriver in subject line)

The Warbird's Forum www.warbirdforum.com
Expedition sailboat charters www.expeditionsail.com