Measurement and Linear Prediction of Motion and Wave Load Spectra on HMCS Nipigon


  1. Stredulinsky, D.C.
  2. Pegg, N.G.
  3. Gilroy, L.E.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN)
During early December 1997 a sea trial was conducted on HMCS NIPIGON to measure structural loads in moderate seas. During the trial seventy-one dedicated runs of 20 minute duration were conducted at constant speed and heading. The runs were conducted at two speeds in head, bow, beam, quartering and following seas, with significant wave heights ranging from 1.4 m to 5.5 m. During each run, ship motions, hull pressures, hull girder strains, and local strains in the vicinity of a hatch were recorded as digitized time series and analogue tape recordings. A wave buoy was used to measure directional sea spectra during the runs. This paper presents a comparison of measured ship motions and bending moment loads with predictions obtained by combining motions and bending moment transfer functions with the directional wave spectra. The motion and load transfer functions were obtained with the DREA code SHIPMO7 (based on linear strip theory) and a proprietary 3D linear hydrodynamic code PRECAL 2.0. PRECAL was also used to predict hull pressure transfer functions which were combined with the measured wave spectra to predict hull pressure spectra. The sea trial has provided a large data base of wave spectra and ship motion, hull pressure and strain time series during dedicated runs under a variety of sea states and ship operational conditions. TRUNCATED
Computer programs (PRECAL)
Report Number
DREA-SL-1999-020 — External Paper
Date of publication
01 Mar 1999
Number of Pages
Hardcopy;Document Image stored on Optical Disk

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