It seems that underwater eruptions of volcanos can pose significant challenges to navigation. Most of us know about Kick 'em Jenny and how it affects buoyancy in the Caribbean. A recent vast raft of pumice in the Pacific is apparently not an unusual occurrence. It made me wonder if the pumice poses a hazard to navigation and what the actual ramifications could be. I imagine that small bits sucked into the saltwater intake could pose significant problems if the engine is running. Could there be an issue with the collision with the pumice or is it light enough and fluid enough to part without damage?  

https://www.nytimes.com/2019/08/27/world/australia/pumice-raft-coral.html?te=1&nl=science-times&emc=edit_sc_20190903?campaign_id=34&instance_id=12084&segment_id=16678&user_id=b9a8dfbb204099e98df802eb0186aa4d&regi_id=21860213

Vice Commodore, OCC 

Sandy, that's cool. Thanks for the link which contains a link to the full text of the book online. 

I should have posted a request from scientists for sailors to report sightings and collect samples to deliver once they reach Australia. Here it is. Contact info appears in the box on the left. 

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Vice Commodore, OCC