This package provides tools for simulating the collisions of ships with whales, using a simplified dynamical structure involving point masses separated by compressible materials. Along with functions for computations of forces, deformations, accelerations, etc., the package provides a easy-to-use GUI tool that makes it easy to set up some common simulation scenarios, and to display the results in graphical form.
To learn more about the scientific background, and to see the results of some detailed computations placed in the context of a database of observed strikes, see Kelley et al. (2021). For more information on the coding, see Kelley (2024).
The package is not yet available on CRAN, and must be installed from source. This can be done either by downloading the source and building it locally, or by the simpler method of typing
# install.package("remotes")
remotes::install_github("dankelley/whalestrike", ref="main")in an R session. (Uncomment the first line, if the
remotes package is not yet installed on your machine.)
Most users will find that the GUI application is a good way to learn about the package. To start this, type
library(whalestrike)
app()in an R session. A window will open in your browser. On the left-hand
side is a region with controllers, many hidden in sub-panels that can be
opened by clicking on V-shaped icons. Before opening those sub-panels,
try adjusting the ship speed, to see what happens to the plots,
especially the one labelled Lethality Index. Think about
whether the tendency of variations to the index are in line with your
intuition. Next, open the Ship sub-panel, to explore the
result of altering the ship mass. This sub-panel also has controllers
specifying the geometry of the impact region, and you ought to explore
them, also. Continuing to explore the app’s controllers ought to give
you a good indication of what the tool provides. To learn more, try
consulting the app’s documentation, provided (a) as the response to
typing ? app in the R console, (b) as information in a
dialog box that opens when the Help button is clicked, and
(c) in a youtube video and a
brief followup youtube video
that illustrates an alteration made after a helpful comment from a
review of a Journal of Open-Source Software manuscript about the
package.
Users who want more control, and who want to deal with the results in
numerical as opposed to graphical form, should try clicking the
Code button in app(), to see the R code that
runs the simulation outside the app. The next step will be to explore
the functions used in that code. Documentation exists for each of these
functions e.g. typing
library(whalestrike)
?strikein an R session will provide information on strike(),
which is a key function in the package.
Kelley, Dan E., James P. Vlasic, and Sean W. Brillant. “Assessing the Lethality of Ship Strikes on Whales Using Simple Biophysical Models.” Marine Mammal Science 37, no. 1 (January 2021): 251–67. https://doi.org/10.1111/mms.12745
Kelley, D. E., (2024). whalestrike: An R package for simulating ship strikes on whales. Journal of Open Source Software, 9(97), 6473, https://doi.org/10.21105/joss.06473