I know of one case where mast pumping was blamed for compressing the mast step,
which led to severe pumping and rig failure. While the primary fault in this
case was a design flaw in the step, it shows that pumping can stress the system
in unusual ways. BTW, I know of a number of boats that don't worry about
pumping, though they check their rig more frequently than the above mentioned
boat.



"MLapla4120" wrote in message
...
Hi,
I have a sailboat and when it gets windy at the slip, sometimes there is
a vibration and the mast and rigging seems to resonate and vibrate. Someone
told me this is 'mast pumping'. I was also on another sailboat visiting and
it
did it also. Nobody seemed concerned.
My question is; should I be concerned? We get regular wind here at twenty
knots and sometimes more. The pumping seems to last about 3-5 seconds.
Then, it stops and resumes a little later.

Thanks for any info.