The fibrous husks of cocoanuts are prepared in such a way as to form "cellulose," which is used for the protection of warships, preventing the inflow of water through shot holes.

The United States adopted the preparation for this purpose in 1892.

It is very light and compressible and when tightly packed between the steel plating and the side of the vessel will expand when wet and fill up the space through which a shot may have passed.

Another and cheaper product experimented with is the pith of the cornstalk, which is much lighter than the cocoanut fiber and serves the same purpose.