Coastguard rescue teams and the RNLI say they're carrying out a search and rescue mission after a Personal Locator Beacon (PLB) was activated.
The emergency service says the only confirmed information is the beacon is within a radius of 5 miles of Snaefell, which it calls a massive search area.
The coastguard is asking all boat and locator beacon owners to check theirs to make sure it's not been accidentally activated.
If you have any information or find an activated beacon, you should contact the Marine Operations Centre on 686628.
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