eruptn 95 Posted August 26, 2019 Share Posted August 26, 2019 A submarine eruption started near Tonga on August 8 and has produced a reasonable pumice raft that heading of to the west at present. It can be seen on lots of satellite images and is now getting some media attention. I nice video clip can be seen here: https://youtu.be/PEsHLSFFQhQ This article has a nice compilation of the satellite images; https://www.stuff.co.nz/world/australia/115251006/sailors-discover-rock-carpet-floating-towards-australias-great-barrier-reef Quote Link to post Share on other sites
Hurts 6 Posted August 26, 2019 Share Posted August 26, 2019 I’d really love to see a pic of the underside of the boat after a couple of days of sailing through that stuff. Possibly super faired antifoul or all paint missing - unsure just how abrasive that stuff is? Quote Link to post Share on other sites
southernman 73 Posted August 26, 2019 Share Posted August 26, 2019 I sailed through that stuff in 2006/7 around Tonga, was really abrasive, some of the chunks were huge. At the time we had a steel boat, really worried about losing the paint but it was fine, however it really did clean up the antifoul. Quote Link to post Share on other sites
Island Time 1,220 Posted August 26, 2019 Share Posted August 26, 2019 Very hard on cooling systems. Sailing is better, don't run the engine in a pumice raft! Quote Link to post Share on other sites
Steve Pope 243 Posted August 26, 2019 Share Posted August 26, 2019 There is a clip of a yacht that had just sailed through a pumice raft, when they looked back the water they had sailed through looked like it was boiling, how lucky they were !!! I wouldn't imagine there would be a lot of bouyancy if you were in it plus whatever other nasties / fumes etc Quote Link to post Share on other sites
Steve Pope 243 Posted August 26, 2019 Share Posted August 26, 2019 There is a clip of a yacht that had just sailed through a pumice raft, when they looked back the water they had sailed through looked like it was boiling, how lucky they were !!! I wouldn't imagine there would be a lot of bouyancy if you were in it plus whatever other nasties / fumes link Quote Link to post Share on other sites
eruptn 95 Posted August 26, 2019 Author Share Posted August 26, 2019 Very very abrasive, basically tuff glass. Google SEM pumice to see images like this; Quote Link to post Share on other sites
Fogg 427 Posted August 26, 2019 Share Posted August 26, 2019 Crikey! Trying to work out if the crew in that clip were brave or foolish! Quote Link to post Share on other sites
wheels 543 Posted August 27, 2019 Share Posted August 27, 2019 This is more common than I think many of you realise. The first time this particular event was reported was back in 2012 and there have been several similar news stories over the years since then. The Volcano is the Havre Sea Mount.The area is thousands of metres deep. It would be impossible for the Sea to boil. It was probably the Pumice shooting up to the surface and the gasses being released from the rock and maybe the Volcano below.There was an account back in the late 1800's where a Volcano erupted under the sea and produced a Pumice field that was 1.6m deep on the surface.While safe to sail through, it is not wise. The abrasive material can badly scratch the Hulls paint work and small bits of Pumice can block water intakes. Quote Link to post Share on other sites
darkside 61 Posted August 27, 2019 Share Posted August 27, 2019 There was a similar event in 95 when we were in Vavau. It even formed a small island for a while which they were going to name after Lomu which is referenced here. https://www.stuff.co.nz/world/south-pacific/65103454/ The raft we sailed through going to Fiji was much lighter than this years however. Don't underestimate the gases however. There is an exclusion zone off Grenada around an underwater volcano called Kick'em Jenny. We asked the locals about the exclusion zone and were told if it belches, you sink. Quote Link to post Share on other sites
Island Time 1,220 Posted August 27, 2019 Share Posted August 27, 2019 I agree the expelled gasses could be both toxic, and if in sufficient quantity, especially small bubbles, could reduce the water density enough to make floating a problem. This is a known issue in whitewater rivers - a life jacket does not necessarily keep you head above water, or in extreme situation, even a kayak. They do come back to the surface in the end though. Quote Link to post Share on other sites
Fish 0 Posted August 27, 2019 Share Posted August 27, 2019 Its also a known hazard in wastewater ponds. Where the sewage is highly aerated with blowers. It is not possible to float in it at all, with a life ring or anything. Hence substantial fencing and security around wastewater treatment plants. Drowning in sh*t isn't just a metaphor for a bad day at work, it is a real risk. I couldn't think of much worse... Quote Link to post Share on other sites
wheels 543 Posted August 28, 2019 Share Posted August 28, 2019 One of the very few actual sinkings (most sinkings attributed to the area have been found to be no where near it) in the area called the Burmuda triangle was caused by Gas bubbles. If I remember rightly, it was a Barge being towed and it sank behind the Tug. The Tug was clear of the Gas and floated OK, but the towing cable being really long meant the barge was some distance back. It went down in daylight and was witnessed be those aboard the Tug, hence they now what it was. Apparently Methane coming up from the sea floor. Quote Link to post Share on other sites
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