Dropping anchors - end of the myth?
Type:
Presented during:
CEDA Dredging Days 2005 - Dredging: The Extremes, Rotterdam
Authors:
Luger D. and Aanen L.
Abstract: Past experience in the evaluation of the risk of dropping anchors learned that many uncertainties about the actual anchor behaviour exist. As a consequence velocities of falling anchors were often negotiated rather than calculated. To put an end to at least part of this knowledge gap a series of model tests was performed in the labs of GeoDelft and WL|Delft Hydraulics with sponsoring of major industrial partners. Several common anchor types were tested to determine drag coefficients. The results give a good feeling for the drag coefficient values which may be encountered for these and similar anchor types.
Another aspect concerned the trajectory during the free descent of the anchor. Video registrations of falling anchors both confirm the other fall tests and provide data with regard to horizontal component in the velocity. An anchor which falls straight down proves to be exception rather than rule.
All resulting data are presented in the paper and can be used as direct and easy accessible background in design of anchor protection schemes or determination of dropping anchor risk assessment.
Keywords: anchor, drag coefficient, penetration, dropping