The Coastguard received a report of somebody in the water near the Caernarfon changeover buoy. On arrival the lifeboat found 2 young men(early twenties)with a powerboat stranded on a sand bank. One had tried to swim ashore to get supplies but had returned to the boat safely. They were on their way to Forfa Nefyn and insisted that they were happy to stay with the boat until the tide floated them off and then complete their voyage. The lifeboat helmsman recommended that rather than travel at night they should take the boat out at Plas Menai. The boat had no anchor or VHF.