In August, 2019, an underwater eruption off the west coast of Tonga produced a large raft of pumice. It gradually broke up into several smaller rafts which were tracked between Tonga and Fiji.
In early October, a pumice raft started to show up floating through our anchorage near Nananu-I-Ra. Moving about with all this debris at the surface could scratch the hulls. Running engines could result in fine bits of sand getting into the engines, possibly seizing them, NOT A GOOD THING! Fortunately, we were here for kiting and had no immediate plans to move the boat. Whistler remained anchored, with her engines off.
One afternoon, we went out with Warren from Safari Lodge on a downwinder and kited down to Nananu-I-Ra. Long streams of pumice were everywhere. When our kiteboards crossed through it, it made a SHHHHHH sound, similar to skiing through a layer of ice crystals. We did our best to avoid hitting the bigger chunks. Like glade-skiing I tried to look between the trees, instead of at them! The scratches on the bottom of our kite boards tell the story of the day. One fellow kiter delaminated his board when he hit a large block of pumice the size of a football.
When I was took a rest from kiting, floating in the water, the pumice gathered all around me. Taking our harnesses and wet suits off at the end of the day was humorous as bits of pumice fell out on our deck!
Ten days later, more pumice was continuing to stream through the area. Here is a video we put together.
Thanks for watching! We look forward to your comments. Keep well!
Cool but hazardous experience. Never seen that before
It is good you have not operated your engines near the pumice. It seems that a risk is the pumice entering the cooling water intake and engine cooling water jacket. I assume that your engines have sea water directly to the engines for cooling. One risk is the pumice plugging the water intake or water pump or cooling water passages in the engine water jacket. I don’t know what is the biggest risk. I wonder if anyone has developed a solution to keep the pumice out of the cooling water system, or included a way to back flush and clear out any blockage. Anyways more fun.