otnmbrd wrote:
"Matt Colie" wrote in message
news:
What I am waiting to see the impact of is the Double-Double
tankers.
These are double hull tankers with twin power plants and even
including
twin sterring engines - complete redundency. No single device
failure
can leave the ship without manuerving capability.
Matt Colie - Licensed Marine and ex-tankerman

Bob Crantz wrote:

I thought double hulls would end all spills.




No way that "double hulls" will guarantee no spill a la Exxon
Valdez...... there's a good chance that even with a double hull, she
would have breached some tanks, considering how far up into the hull the
rocks went, though hopefully the cargo tank breaches will be greatly
limited versus single hull vessels.
One big question still remains and hopefully won't be answered..... a
1,000' container ship doing 25k slams into the side of a tanker. How far
will she penetrate if she hits between webframes?
BTW all ships have multiple steering motors.... it's the rudders that
are generally singular.

Keep in mind "otn's law"
Anything designed by man, built by man, operated by man, maintained by
man is subject to catastrophic failure due to any one or combination of,
the above factors.

otn
otnmbrd
I did not say multiple motors, I said steering engines (admittedly
misspelled). The vast majority of ships out there have ONE Steering
engine. That is one single hydraulic unit that may have twin circuits
(most do not) but most do have two motors for two hydraulic pumps. This
even goes for the rare twin shaft/twin rudder ship. Those that I have
run have that do have twin rudders still have a single steering engine
with the requisit two pumps. This new class of Double-Doubles actually
have two steering engines - one per rudder. What I have not confirmed
is if this class still has the redundent hydraulic pumps on each
steering engine.
Matt Colie

Matt Colie wrote in
news:

otnmbrd
I did not say multiple motors, I said steering engines (admittedly
misspelled). The vast majority of ships out there have ONE Steering
engine. That is one single hydraulic unit that may have twin circuits
(most do not) but most do have two motors for two hydraulic pumps.
This even goes for the rare twin shaft/twin rudder ship. Those that I
have run have that do have twin rudders still have a single steering
engine with the requisit two pumps. This new class of Double-Doubles
actually have two steering engines - one per rudder. What I have not
confirmed is if this class still has the redundent hydraulic pumps on
each steering engine.
Matt Colie


Possible question of semantics as well as aging memory.
I think I see what you are talking about, but I need to check something, as
I think the required redundancy runs further down the system than you are
saying.

otn

otn,
If you find out, I'd like to know. I let ME/log($) slip when I left he
industry. I am not as on top of things as I might like.
Matt

otnmbrd wrote:
Matt Colie wrote in
news:


otnmbrd
I did not say multiple motors, I said steering engines (admittedly
misspelled). The vast majority of ships out there have ONE Steering
engine. That is one single hydraulic unit that may have twin circuits
(most do not) but most do have two motors for two hydraulic pumps.
This even goes for the rare twin shaft/twin rudder ship. Those that I
have run have that do have twin rudders still have a single steering
engine with the requisit two pumps. This new class of Double-Doubles
actually have two steering engines - one per rudder. What I have not
confirmed is if this class still has the redundent hydraulic pumps on
each steering engine.
Matt Colie



Possible question of semantics as well as aging memory.
I think I see what you are talking about, but I need to check something, as
I think the required redundancy runs further down the system than you are
saying.

otn

Matt Colie wrote in
:

otn,
If you find out, I'd like to know. I let ME/log($) slip when I left
he industry. I am not as on top of things as I might like.
Matt


G I go back on duty this week so I should have some chance to view either
systems or schematics.
The last system I knew closely had two motors, two hydraulic pumps and four
rams (pistons) driving the yoke.
The four rams driving the rudder yoke is what I want to check on, as I
think these could be individually isolated if a problem arose while
maintaining steering.

otn