Rubber Strip in Bilge - R16

[eFlat]

Was rinsing out the bilge on my R16 and checking things out when I found two of these.  It's a heavy rubber strip about 2" wide and 3' long. One was loose and the other seems to be laying flat on the floor from stern to bow. 

The loose one was wrapped around my bilge pump is the reason I noticed it.

Any idea what they are? 

[mulligan]

Maybe from under the gas tank?