3505. Early Stage Weight and Cog Estimation Using Parametric Formulas and Regression on Historical Data

Paper

Abstract

Estimation~ of~ weight~ and~ center~ of~ gravity~ is~ an~ essential~ task~ in~ the~ design~ phase~ of~ a~ vessel,~ and~ the~
quality~ of~ this~ work~ will~ be~ crucial~ for~ the~ success~ of~ the~ project.~ It~ is~ important~ to~ have~ the~ best~ possible~
estimate~ for~ total~ lightship~ weight,~ but~ when~ it~ comes~ to~ construction~ and~ installation~ there~ will~ be~ a~
demand~ for~ detailed~ budgets.~ A~ certain~ detail~ level~ for~ the~ weight~ budget~ will~ also~ make~ it~ easier~ to~ find~
the~reasons~for~any~deviations~that~may~occur~during~the~monitoring~phase.~
The~ use~ of~ parametric~ estimation~ based~ on~ several~ reference~ ships~ and~ regression~ lines~ has~ traditionally~
been~ characterized~ as~ too~ demanding,~ because~ of~ time~ demands~ as~ well~ as~ complexity.~ This~ article~ will~
describe~ some~ assumptions~ and~ methods~ that~ make~ it~ possible~ and~ preferable~ to~ use~ parametric~
estimation~ on~ a~ regular~ basis~ when~ designing~ and~ building~ a~ ship,~ either~ by~ the~ use~ of~ built-in~ formulas~
and~ graphs~ found~ in~ spreadsheets,~ or~ by~ the~ use~ of~ database~ related~ weight~ control~ systems~ like~
ShipWeight.~ This~ article~ will~ discuss~ topics~ like~ breakdown~ structures,~ methods,~ selection~ of~ coefficients,~
selection~ of~ detail~ level,~ reporting~ and~ exporting~ of~ results,~ together~ with~ design~ changes~ and~ re-
estimation.