Up the Allegheny
June 27, 2009
So far, I'd managed to sail from the Newport Marina downstream of
the West End Bridge as far as the Point. It was time to realize one of
the founding ambitions that had put me on the river in a sailboat in
the first place. This time, I'd resolved, I'd sail up the Allegheny.
My goal was the bridges at 6th, 7th and 9th street. That little
stretch of the river is one of the most beautiful I've ever seen,
anywhere in the world. It has a spectacular view of the city skyline,
framed by the magnificant bridges. The scene is smaller than the vistas
at the point. But that brings everything closer and fills your field of
view, left, right, up and down. You feel less like a distant spectator
and more a part of the panorama.
The trails that run alongside are my favorite place to run. Each
time I run there, I conjure little dreams of sailing--on the gentle
waters under the magnificent spans.
The weather forecast and river currents showed the window for
sailing on the river was coming on this Saturday. Then, winds at 9 mph
from NNW were forecast; and the plots of the river currents were
showing that the flows were now returning to normal after the
floods.
We packed ourselved up in the morning for our day. Eve had a 25 mile
bike ride planned. I would sail.
Ours is an interesting block downtown. There always seems to be
something happening. I steer my bike, laden with sailing gear, onto the
street, never sure what I'll find. Last time I stepped into the middle
of the gay pride event. This time, there were no rainbow colored
shorts. Arrayed outside Planned Parenthood, a hundred feet or so from
my front door, was a group of antiabortion protesters. They were
flanked by a small group of yellow t-shirt clad Planned Parenthood
guides.
It seemed more prudent to walk the bike through this little group; I
didn't want to run anyone down. As I passed, they burst into hymns that
I presumed were aimed at me. The logic was a little hard to follow.
Someone pushing a bike, wearing a lifejacket, with a dangling wind
speed gauge is not heading for church.
The ride over the bridges and down the river was encouraging. There
was a current on the Allegheny, but it was a slow walk. The winds were
steady at about 6 mph, whereever I measured them. That was how it
should be. Not too much; not too little; and steady.
Once I arrived at the marina, I began the ritual of rigging the
boat. This is an especially easy boat on which to step the mast and
then rig. Still, doing all the little bits and pieces took 30 minutes.
I spent a little time sponging off dirt and bird droppings. No doubt
even Ulysses had to handle such problems in his great journeys,
although they eluded Homer's narrative. Then I was in the water, ready
to head off. Twigs I'd thrown in the water showed a slow walking pace
current. It was nothing too much to fuss with, as long as there is
wind. (Allegheny River at Natrona, 14,000 cubit feet per second; Mon at
Elizabeth, 2,500 cubic feet per second.)
I set off on a broad reach--that is, the wind is as close to
directly behind you as you can get. I was soon passing the familiar
landmarks: the West End Bridge, the Science Center with its submarine,
Heinz Field, and more. There was not much to do on this point of sail.
Since you are being blown with the wind, everything is calm and there
is no real sense of movement, until you look back at the bubbling wake
and the gash it leaves behind in the water. It was most comfortable to
kneel in the middle of the deck. I was much more relaxed, now, feeling
in better command of the boat.
It was a warm and sunny day and there were many kayakers on the
river. One of the transforming moments in Pittsburgh's river history
was when Kayak Pittsburgh started renting kayaks on the Allegheny River
at a ramp underneath the 6th Street Bridge. Several kayakers were
slowly made their way over to me and began to flank me, something like
dolphins around ship at sea.
Once you know the trick, you don't need a speedometer to gauge your
speed on the water. You need to learn one conversion factor. How fast
are you going if a bit of debris takes one second to pass the length of
your hull? For my 12 foot hull, that number is 8.2 miles per hour or
7.1 knots.
I began counting off my speed. In better breezes, the debris was
passing in about 2 seconds; that is, 4 miles per hour.
8.2
mph x 1 sec = 4.1 mph x 2 sec = 2.05 mph x 4 sec
Not bad, but slow. Our big Hobie could attain 20 miles per hour, but
that is a very different experience.
In about 30 minutes, I'd arrived at the Point. That seemed about
right, given that my dock was 1.25 miles downstream of the Point. There
seemed no reason to dock at the Point. The winds were blowing gently
but steadily straight upstream. Best just to keep going. So I pointed
my bows (there are two on a catamaran!) straight up the Allegheny
River. Everything went well until I neared the enormous span of the
Duquesne Bridge. Then the wind just seemed to die. I spent an anxious
minute with my bows pointed upstream locked in one place, wondering if
this was as far as I'd get. Would I be Moses, destined to die in the
desert with the promised land in sight?
Then the winds revived. Some 20 minutes after passing the Point I
had moored at a dock just upstream of Kayak Pittsburgh, between the 6th
and 7th Street Bridges.
What makes boating so much fun on the rivers is that you get a
completely different view of the city. There's nothing quite like
seeing one of the magnificent bridges as it passes directly overhead.
The many kayakers and this lone sailor this day were having more fun
than anyone else in the city.
In order to mark the event, my first sail up the Allegheny, I took
photos of the boat; and kindly bystanders took photos of me with the
boat, with me trying not to look too smug.
I called Eve to see if her ride was over. This was too much fun for
her to miss. After a few missed connections, we arranged for her to
ride her bike over. Soon we were both sitting in the boat slicing
through the water, directly across the river.
While the wind is steady, it does get deflected by the obstacles in
this stretch of the river: bridge pylons, waterfront buildings. So
sailing rarely proceeds for long in a straight line.
What now made this little complication more awkward, was the serial
appearance of large things. "Keep an eye out for big boats," I said to
Eve. No sooner was that said than a big paddle wheel steamer appeared
downstream, aimed directly at us. I turned back to the northern side of
the river, since the larger boats navigate in channels that seem to lie
on the southern sides.
This evasive cycle repeated as first one huge barge and then another
decided to share this stretch of the river with us. Of course "share"
is not quite the way it works. They arrive, moving fast, and we stay
out of their way.
Since Eve's bike was locked up at the 6th Street Bridge, we couldn't
go too far afield. So I started the long tack back to the marina,
letting Eve off just upstream of the Duquesne Bridge.
The voyage from the marina had been easy. I sailed on a broad reach
with the wind behind me. The return would be harder and slower. The
wind is blowing directly along the river from downstream, exacly where
I'd need to sail. That means tacking back and forth, again and again.
In one regard, it is more fun. With the wind coming obliquely over
the bows, the boat moves a lot faster in the water. It's fast and its
fun. But in another way, it is slow. You spend your time bouncing like
a tennis ball to and fro across the net. At first it seems that you are
getting nowhere at all for all the effort. You soon learn to gauge your
progress by marking points on the shore. I start ticking them off. On
this tack, we are at the conning tower of the submarine. Now--off,
across the river and back. We are now in line with that piece of heavy
equipment at the casino building site. This is the journey home. It is
fast sailing that gains distance in small doses of a few hundred yards
at a time.
I forgot to count off the speed, but my sense now is the we easily
made the one second-to-pass-the-hull time. That means we easily made 8
mph.
Sailors: this is a catamaran, so it is
not bound by the usual rule for hull speed, governing ordinary
displacement hulls:
Hull speed (knots)
= 1.34 x Square root (Length at waterline in feet)
That comes out to 3.8 knots = 4.3 mph for a 12 foot boat. That is the
maximum speed an ordinary 12 foot boat can go. Efforts to push it
faster simply create more hydrodynamic forces that pull the hull deeper
into the water. That makes the boat harder to move and defeats efforts
to speed it up. The only escape from this cycle is to use a powerful
enough force to get the boat to hydroplane. Catamarans are free of this
hull speed limit for reasons I don't quite understand. It's something
to do with replacing the bulky monohull with two knifelike catamaran
hulls. In any case, it's a really good reason to sail a catamaran on
the river when there can be currents to beat!
From
http://en.wikipedia.org/wiki/File:Speed-length_vs_weight-resistance.gif
The quantity on the horizontal axis is probably misstated. The
magnitude should be the ratio of speed divided by (square root of
length). That way the usual hull speed rule is recovered when the ratio
is 1.34, the value at which resistance "blows up" for displacement
hulls. My guess is that the horizontal axis is intended to be this
latter ratio. It was the one Froude defined in his 19th century studies
of hull resistance and is commonly called the "speed length ratio."
That doesn't mean it is computed as the ratio of speed/length!
In retrospect, the disasters of my first two sailing days on the
river, were not just inhospitable winds and currents. It was also my
own ineptitude with the boat. I now knew it much better and could
swivel and twist about on the deck with fairly fluid movements, as I
moved between the various seating positions needed. The business of
tacking into the wind is all about sailing as close to the wind as you
can get. I was now better able to judge how close was too close. I'd
also learned to leave the sail out as I pointed closer to the wind and
only then to haul it in tight; that little trick minimized the chance
of an overpowered sail on a beam reach--that is, side on to the
wind--tipping the boat.
The journey had taken a little over 30 minutes on a broad reach. It
now required about an hour of tacking to go in the opposite direction.
After I had pulled into the marina, I noticed that the current had so
subsided as to be unnoticeable. I'd gotten no help from it.
I was getting smug. As I approach the marina ramp, I could see a
large powerboat in the process of being launched. It had stopped half
way down as its sailors fussed with the rudder and screw. I took my
moment and brazenly sailed into the ramp's little channel, in full
sail, turning at the last moment to beach right where I stored the
boat. "Slick," I thought to myself. The powerboat sailors didn't know
that they'd just seen a little display sailing machismo. They'd just
seen some guy in a sailboat and silly hat go by. They'd chuckle if they
heard I thought 8 knots was fast.
In about 20 more minutes, I had the boat out of the water and back
on its trailer, the mast down and all the gear stowed. I was back on my
bike and cycling home.
Once again, I marvelled at the extraordinary density of downtown
living in Pittsburgh. In moments, I'd passed from a sailboat on a quiet
green, stretch of the river; along trails, with people walking, running
and strolling; past kayakers scooping their way under bridges; past a
football stadium and a baseball park, where the strains of the music
flowed out onto the riverbank; past the traffic of a full-blown
downtown, with restaurants, bars and skyscrapers; past the scene of the
morning's demonstration; and into my living room. We were visiting
friends for dinner. Still in my sailing gear, I walked to the liquor
store, just a few doors away and made my wine selections. I was, at
that moment, hard pressed to imagine any city in the world that could
match that experience.
John D. Norton
|