FERRYSIDE, CARMARTHEN BAY.—On the 21st August, in a strong wind from the S.W. and a rough sea, the yacht T. Deryon,of Carmarthen, was observed to be dismasted and in dangerous proximity to the Langharne Sands. Tie Life-boat City of Manchester, stationed at the Ferryside, went out to her, and found that her mast was broken off about twelve feet above the deck; the crew had, however, succeeded in setting a small sail to the remains of the mast, and had weathered the Sands. At the request of the crew of the yacht, the Life-boat then accompanied her, and indicated the best position to take the beach, and that having been safely accomplished, those on board were helped ashore..