|Autoload/Rig: Next-Generation Stability
Software for Semi Submersible Rigs.
Not all stability software is made equal. Even if all
commonly available stability programs were of the same
quality, virtually all of them are designed first and
foremost for conventional vessels - and it's no secret
that the unique characteristics of offshore platforms
demand capabilities not usually required for ships.
Rig stability is a very critical issue, and it can also
be quite complex. What rig operators need is software
that can constantly monitor and predict stability in
any combination of circumstances; but what they don't
need is an interface as complex as the problem.
Enter Autoload/Rig - only recently released,
yet already installed on more then 15 platforms, Autoload
has also been chosen for the biggest floating rig ever
Autoload/Rig was designed specifically for the
Offshore industry, with a completely new interface resulting
from rig operator recommendations. From the start, Autoship
Systems Corporation (ASC) adopted a simple philosophy:
with one brief look at the screen, you must be able
to get a clear picture of the vessel's current stability
status, loads, and important margins. Quick and accurate
understanding means that you are better able to make
critical decisions, while leaving the mathematical complexity
of the problem to the computer. In addition, Autoload/Rig
is designed to be tailored to virtually any customer
or vessel-specific requirement.
ASC spoke with rig operators and designers, and what
the industry told them was that critical information
needs to be readily identifiable, must not be hidden,
and must always be found in the same place. It's interesting
that this is not the trend in most software for desktop
computers - the normal Windows environment presents
you with layers of windows, each capable of being closed
or minimized. There are reasons why this paradigm is
popular, not the least being that it allows you to put
up any combination of data
but it also places
the onus on the user to organize and keep track of all
that data. That's great if you are writing a memo and
attaching a spreadsheet, but doesn't help you get a
clear picture when time is short and the conditions
are less than optimal.
Never afraid to question a trend, ASC listened to the
industry and produced an interface that achieves the
balance between clarity, simplification, organization,
and inclusion of data. Autoload/Rig's interface
is based on understanding the three main functions required
in an offshore stability system: it must help you set
up and monitor the vessel's loading condition, check
all relevant margins, and report the results. The interface
is divided into four main parts:
essential tools for making settings, creating reports,
and managing condition files.
Floating Status Frame
clear, well-organized display of floating status, including
all hydrostatic parameters and stability margins.
graphical representation of the vessel, loads, and floating
position - which changes with any change in loading.
Includes both environmental forces (wind) and marine
loads (mooring and risers). You can enter loads (and
even set compartment damage) directly within the rig
contains tables for showing and editing all loads, divided
into tank loads and "fixed" (non-liquid) loads.
Autoload/Rig - General User Interface
This new interface, and the software features behind
it, proved to be so desireable that ASC decided to develop
it for use on conventional vessels as well (as Autoload
Version 6.0). As a result, the "new" interface
developed from Autoload/Rig is now being used
on a tanker vessel operated by Teekay Shipping Ltd,
and is being installed on several new-build bulk carriers
for Westwood Shipping Lines.
Even though the interface clearly reflects the needs
of the Offshore industry, it is still important to look
behind it - after all, in the software industry what
you see on the screen may not always be representative
of what you are actually getting. Fortunately, though,
Autoload's hydrostatic engine - the software
at its heart - is based on experience gained from 20
years of providing hydrostatic prediction software (Autohydro)
for vessel designers, and stability software for the
marine shipping industry. Autohydro is used by
over 1000 engineering companies around the world, and
is tested and approved by most governing approval bodies.
In the offshore market, major design offices like GVA
Consulting and the Aker & Kværner Group have
been using Autohydro for rig stability for more
then 15 years. Just as Autohydro is the industry
standard for offshore design offices, Autoload
Rig is proving very popular with the rigs designed by
these offices - because they both rely on the same 3-D
mathematical model. In other words, the same rig model
is used in both the design process and actual operations.
The importance of this model should not be underestimated.
The vessel model is a key element in the accuracy and
flexibility offered by Autoload. The model is
truly 3-D and is inclusive of all volumes (tanks, holds,
empty spaces, etc). The mathematical treatment of this
model gives a true simulation of any floating condition,
including real shift of CG for slack tanks, true wind
heeling moment, and accurate damage simulation (loss
of buoyancy method). If a table-based system is designed
to give comparable outputs, it would simply be incapable
of achieving the level of accuracy represented by Autoload/Rig.
The flexibility and accuracy provided by both the 3-D
model and a proven, state-of- the-art hydrostatic engine
is also key to fulfilling the specific requirements
of the offshore industry. Challenges specific to offshore
With Autoload's 3-D model you can easily predict
the effect that damage will have on stability in any
direction; the software calculates real shift of free
surface in slack tanks according to any change in heel
or trim. Real-time sensor data is used for tank contents,
drafts, mooring tension, riser tension and wind, while
the software accommodates different sets of criteria
for different modes of operation. A separate view frame
monitors the actual maxVCG curve relative to the current
Finally, ASC hasn't forgotten to account for the time-honoured
programmers dictum, "nonsense in, nonsense out
(replace the word "nonsense" as you please).
What if data that should have been manually entered
somehow gets omitted? What happens if a sensor is mis-reading,
or if an operator enters incorrect data? This is where
the 3-D model of the displacing vessel saves the day:
Autoload/Rig compares the "calculated draft"
with the "real draft", and solves to find
the "constant" weight that accounts for the
difference. If this "constant weight" and
its calculated centre of gravity are within a specified
limit, then the loading condition is considered correct.
If the constant weight falls outside the limits, the
operator is warned and must find the reason for the
If you need stability software for an offshore vessel
of any kind, then it is worth contacting an ASC
dealer for more information.
During the 24 years Autoship Systems Corporation has
been producing world-class CAD/CAM and load management
software, it has amassed thousands of customers - including
the US Navy, US Coast Guard, Newport News Shipbuilding,
Teekay Shipping Ltd, Halliburton Subsea, Rolls Royce,
Westwood Shipping Lines, and Wallenius Wilhelmsen Lines,
plus private companies and government agencies in every
corner of the world.
ASC's latest load management and stability products
include DNV-approved Stowage Management Systems for
ro-ro, container, bulk, tanker, and break bulk vessels
(all with Autoload included in the system). Their
latest CAD/CAM offerings include Autoship 8.3
for hull design and surface modelling, Autostructure
3.0 for internal structural design, Production Manager
3.0 for nesting and other production support, and of
course Autohydro 6.0.