Introduction
We have developed
spreadsheet-based files that have customised cargo work calculations
for a crude oil and product tankers. Our standalone products
are designed for the business of shipping cargo (chemicals, oil or
products) via shipping vehicles (tankers) or storing them ashore or
in floating storage units (FPSO). We prefer to work with Microsoft
Excel (images below are snapshots of Lotus 1-2-3 files).
The latest
products are standalone with a backend database storing the manual
entries for each port of call. The database can be used to produce
all kinds of MLI statistical analysis.
Entries by user
would be:
-
Cargo Ullages
and temperatures tank-wise;
-
Gauge
readings/Soundings of ballast tks;
-
Fuel/FW Tks Qty;
-
Sp. Gr. of Sea
Water;
-
Interface
sounding for free water, if any;
-
V.E.F.;
-
OBQ/Slops on
board, if any;
-
API and/or
Density;
-
Tables required
(6, 24 or 54 A/B); (selectable by mouse click)
-
etc.
Make your own
spreadsheets or standalone projects. Download the add-in dll(s)
with all the functions you need for the tanker
industry.
The results
are transferred to the following with tabulated and/or chart
representations and may be printed at will
-
-
stress pages;
-
Record of V.E.F.
for last 10, 20 and 30 voyages;
-
Charterer's and
Owner's forms, viz. Letters of protest for BL discrepancies,
delays, free water, port log, Ullage Report, Stowage Plan;
-
Etc.
Hydrostatic calculation (draft survey) with hog or
sag deflection is also included.
Customised menus allow macros to run for:
-
Online
registration of tank volumes where such hardware fitted, (We can
undertake turnkey installation of hardware at dry-dock);
-
New Reports;
-
-
Backsolve to required - Nett MT, Barrels, DWT or
Draft;
-
Change SW
density - same cargo/ballast;
-
A scratchpad for
quick conversion from degrees F'ht to C, Ft to M and vice versa
with resultant DWT for that Ft or M.
Also included is the extremely powerful and much used
(by the Chief Officers), add-in called Solver.
Solver provides an optimal solution to various loading/discharging
scenarios in a matter of seconds.
Example:
You have a nominated BL Qtty of 630,000 Nett Barrels of Oseberg
Blend to load from Sture (Salt water) for discharge at Immingham
(brackish). With the given bunker ROBs and load temperatures, draft
restrictions, Solver can find a loading distribution to satisfy the
given constraints which would be - no list, even keel arrival,
volumes <= 98%, minimum stresses, etc.
We offer to write a
similar customized spreadsheet for a fee, for any tanker
operator/owner who may get in touch with us by e-mail for a sample
spreadsheet at: 
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Trim & Stability
The
following is a picture of the bottom half of the "Trim/Stab" page in
the Lotus Workbook. The unseen portion has the data for Provisions,
Constant, FW, Ballast, Fuel / Diesel and Cargo.
KG, LCG and Inertia
Moments are tabled for each and the results are displayed as seen
below.
Results of the
"Stress" page are also incorporated.
An attempt is
made to reflect the actual draft taking into consideration the
deflection due to stresses vis-a-vis the straight girder theoretical
results. This is useful in cases of sailing in shallow waters where
the additional max. draft due to stresses must be taken into
consideration, as too the squat.
Click on Image To Magnify It
Also calculated, is
the loss of GM upon touching the blocks during
dry-docking.
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Back Solve
You may select an
item from the list above to backsolve to.
Example:
You may need to know, with the given the cargo API/Density and
temperatures (which would be entered in the "Ull Rep" page and the
Constant / Fuel / FW / Ballast conditions (entered in the "C Fuel FW
B" page), and the OBQ ("Wedge" page) and Slops onboard ("SlopCert"
page), what the cargo loadable would be for a "Mean-Draft" of 12.192
M Sea Water?
Backsolver would
obtain results for you in a matter of seconds.
The distribution
of the cargo tank-wise with the resultant drafts, trim and list
would not usually be satisfactory. For a satisfactory distribution,
the user would
Click on Image To Magnify It
need to use the "Solver"
facility.
Nevertheless,
Backsolver serves the important purpose of a quickfire answer to
quickfire questions that are posed ever so often to the vessel by
the charterers / brokers. The distribution (stowage plan) may be
obtained more leisurely by using the Solver facility.
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Solver
Solver is an add-in
feature that comes free with Excel (Tools menu). Solver is an
Add-in for Lotus 123 and licenced by Frontline Systems. We provide
this add-in.
In the problem
above -
The set cell is
"AVG-ALL STRESS", which is a cell in the spreadsheet that represents
the average of all the BM and Shear Forces. The demand is to
"MINIMISE" the stresses.
The Changeable
(Variable) cells are "CARGO GAUGES", which are the MMC Ullages in
the table. Additional variable cells may be added, viz. Ballast Tank
Gauges.
The constraints are
many - (up to 100 constraints may be included in this part of the
dialog box). The constraints not seen in the picture above
are:
Click on Image To Magnify It
-
Volumes of each
of the other cargo tanks <=98%
-
Heel Moments = 0
-
Deadweight
<=96,510 (Summer DWT)
-
Nett Barrels =
631,890 (B/L nomination 630,000 * clean VEF of 1.003)
Solver should be
able to come up with an optimal solution in a matter of minutes, if
not in seconds.
In the example
above, the results (solution), will provide a possible loading
pattern keeping to the SetCell demand for a minimised
average of all stresses, a cargo quantity of 631,890 Nett
Barrels, No List, aft trim=0.2M, etc.
Any Chief Officer
would be delighted to use this add-in and it would be redundant to
point out that the cost of the add-in is well worth the time saved
in this aspect of loading/discharging operations.
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Hydrostatic Calculation
Facility is
provided to compute the weight of the cargo on board by hydrostatic
calculations from the draft gauges as well as from the observed
drafts at the draft marks.
Click on Image To Magnify It
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Sample Prints/Wkb Pages
To list of a few
-
Make your own
spreadsheets or standalone projects. Download the add-in dll(s) with all the functions you
need for the tanker industry.
Requirements
Top Of Page
Additional
Information
We have
undertaken smaller projects too - Ullage reports only for crude and
product tankers with results exported to charterer's and owner's
standard forms (ship specific data for tank volumes with trim and
heel correction, stability, stresses and hydrostatic calculations,
etc. not included).
- For Shipping
Companies - Engine
Department.
