http://www.wired.com/techbiz/people/...urrentPage=all

--
"j" ganz @@
www.sailnow.com

Thanks J, a great read about an impressive guy.

Speculation about things like this is a flame magnet but I think it serves a
valuable purpose in helping anticipate and mitigate threats. Being right
about the specific incident isn't the point, thinking about possibilities
that could effect you is.

Having spent some significant portions of my professional life calculating
and thinking about how vessels break, flood, and sink, I find the sinking
by the stern possibility mentioned quite plausible. The problem is that it
requires a hole in the aft part of the boat since vessels usually start to
trim towards the damage. Boats, especially light ones with light ends, will
also usually dissapate a lot of collision energy by the fine forward end
gradually lifting or turning the bow. A sharp heavy object, with it's
effective weight increased by being entrained in the water, could puncture
the forward part of the hull. The nightmare object in my mind is the corner
of a barely floating shipping container lost overboard.

A major hull breech aft is harder to explain but there are two
possibilities, the rudder and prop. An object awash and nearly invisible
might be spotted at the last moment. An instinctive quick turn to avoid it
when the boat was moving fast could swing the stern into it and hook either
the rudder or prop. The geometry of neither is such that much energy would
be dissipated by movement of the hull. Hull failure around the rudder stock
or the shaft pulling out of the coupling (many similar boats have enough
clearance behind the prop to let the shaft come clear of the stuffing box
and shaft tube) could have set off rapid stern flooding and trimming. This
quickly would have cascaded into back flooding through the cockpit scuppers
and then through the companionway which certainly would have been opened to
see why the boat suddenly seemed stern heavy. It would have been very easy
to have focused on plugging a leak and not realized that the companionway
had reached the waterline. The water level would have still have been
fairly low inside the boat at this point and a wave, the stern heavy boat
now having swung downwind, could have sent a large slug of water down the
companionway completing the sinking in seconds.

There is a theory and possibility that Titanic could have survived the
iceberg impact if they had not attempted to turn, thus turning the collision
into the long sideswipe that opened up so many compartments. The same thing
can happen to modern sailboats with their delicate hull appendages. A
sailboat trimming by the stern as it floods will go down a lot faster than
one trimming by the bow.

I wouldn't want this taken as a recommendation to steer straight into any
floating object you see at the last second but, as anyone who has dodged
lobster pots in a separate rudder boat knows, the reverse turn back
"towards" the object is essential to avoidance. Often, when I spot a pot
pulled nearly under by the tide, I find myself close enough that it is
better to just hold the course and hope than to risk swinging the stern into
it by turning. I imagine it would be damn hard to remember that though if
something like a shipping container or giant log suddenly showed up less
than a boat length ahead.

--
Roger Long

"Roger Long" wrote in message
...
Thanks J, a great read about an impressive guy.

Speculation about things like this is a flame magnet but I think it serves
a valuable purpose in helping anticipate and mitigate threats. Being
right about the specific incident isn't the point, thinking about
possibilities that could effect you is.

Having spent some significant portions of my professional life calculating
and thinking about how vessels break, flood, and sink, I find the sinking
by the stern possibility mentioned quite plausible. The problem is that
it requires a hole in the aft part of the boat since vessels usually start
to trim towards the damage. Boats, especially light ones with light ends,
will also usually dissapate a lot of collision energy by the fine forward
end gradually lifting or turning the bow. A sharp heavy object, with it's
effective weight increased by being entrained in the water, could puncture
the forward part of the hull. The nightmare object in my mind is the
corner of a barely floating shipping container lost overboard.

A major hull breech aft is harder to explain but there are two
possibilities, the rudder and prop. An object awash and nearly invisible
might be spotted at the last moment. An instinctive quick turn to avoid
it when the boat was moving fast could swing the stern into it and hook
either the rudder or prop. The geometry of neither is such that much
energy would be dissipated by movement of the hull. Hull failure around
the rudder stock or the shaft pulling out of the coupling (many similar
boats have enough clearance behind the prop to let the shaft come clear of
the stuffing box and shaft tube) could have set off rapid stern flooding
and trimming. This quickly would have cascaded into back flooding through
the cockpit scuppers and then through the companionway which certainly
would have been opened to see why the boat suddenly seemed stern heavy.
It would have been very easy to have focused on plugging a leak and not
realized that the companionway had reached the waterline. The water level
would have still have been fairly low inside the boat at this point and a
wave, the stern heavy boat now having swung downwind, could have sent a
large slug of water down the companionway completing the sinking in
seconds.

There is a theory and possibility that Titanic could have survived the
iceberg impact if they had not attempted to turn, thus turning the
collision into the long sideswipe that opened up so many compartments.
The same thing can happen to modern sailboats with their delicate hull
appendages. A sailboat trimming by the stern as it floods will go down a
lot faster than one trimming by the bow.

I wouldn't want this taken as a recommendation to steer straight into any
floating object you see at the last second but, as anyone who has dodged
lobster pots in a separate rudder boat knows, the reverse turn back
"towards" the object is essential to avoidance. Often, when I spot a pot
pulled nearly under by the tide, I find myself close enough that it is
better to just hold the course and hope than to risk swinging the stern
into it by turning. I imagine it would be damn hard to remember that
though if something like a shipping container or giant log suddenly showed
up less than a boat length ahead.

--
Roger Long



The only thing about the scenario of sinking that doesn't quite wash (no pun
intended) is that there would surely be some debris. Lot's of things would
float and nothing has been found. Of course, it's a big ocean....


--
"j" ganz @@
www.sailnow.com

"Capt. JG" wrote

The only thing about the scenario of sinking that doesn't quite wash (no
pun intended) is that there would surely be some debris. Lot's of things
would float and nothing has been found. Of course, it's a big ocean....

Yes, but a stern first sinking would trap much more than a bow first
sinking. It could have reduced the floaters to the point that they were
missed.

An entire oceanographic vessel disappeared within a few miles of Boothbay
Harbor in the 70's. This was a 40 - 60 foot boat which carried lots of gear
on deck and nothing was ever found in a much more traveled area.

--
Roger Long

JG,

The only thing about the scenario of sinking that doesn't quite wash (no
pun intended) is that there would surely be some debris. Lot's of things
would float and nothing has been found. Of course, it's a big ocean....


The article claims that nothing washed up or was found but that may be
incorrect. If a found a sneaker at the shore I would toss it in the trash
and think nothing of it. Much stuff could have floated away if there was a
wreck or sinking without anything being definitely linked to any accident.

Dave M.

On Jul 25, 12:03 pm, "Roger Long" wrote:
"Capt. JG" wrote

The only thing about the scenario of sinking that doesn't quite wash (no
pun intended) is that there would surely be some debris. Lot's of things
would float and nothing has been found. Of course, it's a big ocean....

Yes, but a stern first sinking would trap much more than a bow first
sinking. It could have reduced the floaters to the point that they were
missed.

An entire oceanographic vessel disappeared within a few miles of Boothbay
Harbor in the 70's. This was a 40 - 60 foot boat which carried lots of gear
on deck and nothing was ever found in a much more traveled area.

--
Roger Long

I would be more inclined to think a ship took him out, or a major
keel failure.

I think the major lesson to be learned if any is make sure your epirb
works before heading offshore. Had he had a self launching/activating
epirb then even if a ship took him out they would know where and when.

Hole punched in stern?

Oh a a point you missed on your Titanic assumption is when ordered
hard astern the wheel walk of the titanic also pulled her stern to
stbd, creating more force against the hull as she grazed the berg.

Just my 2 cents worth.

Joe

"Joe" wrote

Oh a a point you missed on your Titanic assumption is when ordered
hard astern the wheel walk of the titanic also pulled her stern to
stbd, creating more force against the hull as she grazed the berg.

The best evidence, from both ship motion simulators (full size bridge
training versions) and study of the hystorical record, is that Titanic's
engines were never actually reversed. The center screw was non-reversable
and is the only one that would have created significant wheel walk. The
wing screws were along side the keel so very little side flow could be
created by them.

It's actually the lack of side movement or pressure of the hull against the
iceberg that is one of the hardest things to explain about the accident.
The after part of the ship was swinging away from the iceberg by the time
ice reached it.

It's a subject I've had more than usual opportunity to consider but this
isn't a Titanic forum.

--
Roger Long

"David Martel" wrote in message
ink.net...
JG,

The only thing about the scenario of sinking that doesn't quite wash (no
pun intended) is that there would surely be some debris. Lot's of things
would float and nothing has been found. Of course, it's a big ocean....


The article claims that nothing washed up or was found but that may be
incorrect. If a found a sneaker at the shore I would toss it in the trash
and think nothing of it. Much stuff could have floated away if there was a
wreck or sinking without anything being definitely linked to any accident.

Dave M.



I wonder if we'll ever know... too bad for his family.

--
"j" ganz @@
www.sailnow.com

On Jul 25, 12:33 pm, "Roger Long" wrote:
"Joe" wrote



Oh a a point you missed on your Titanic assumption is when ordered
hard astern the wheel walk of the titanic also pulled her stern to
stbd, creating more force against the hull as she grazed the berg.

The best evidence, from both ship motion simulators (full size bridge
training versions) and study of the hystorical record, is that Titanic's
engines were never actually reversed. The center screw was non-reversable
and is the only one that would have created significant wheel walk. The
wing screws were along side the keel so very little side flow could be
created by them.


Do you know what type screws she had outboard to stbd, I'd bet she had
a LH .




It's actually the lack of side movement or pressure of the hull against the
iceberg that is one of the hardest things to explain about the accident.
The after part of the ship was swinging away from the iceberg by the time
ice reached it.

Looking at the gouge is just a small view, you need to see Titanic
bottom for the full picture. Most bergs are 90%+ submerged and the
bottom may have taken a harder shove lessing the side gouge.

http://defiant.corban.edu/gtipton/net-fun/iceberg.html


It's a subject I've had more than usual opportunity to consider but this
isn't a Titanic forum.

It's OK to talk about Titanic stuff here Roger, after all she was
manned by sailors right?

Could you imagine the ride down to the bottom on Titanic? Looks like
she was hauling ass when she plowed into the mud.

Joe


--
Roger Long

"Joe" wrote

Looking at the gouge is just a small view, you need to see Titanic
bottom for the full picture.

I've actually seen more of the Titanic's bottom than all but a roomful of
people on the planet.

--
Roger Long