Young William lost Malltraeth 1802

Wooden full-rigged ship built Whitby 1794, 460tons(bm)
Voyaged to Botany Bay for British East India Co., also to China.
1799 had 20 9-pounder guns, made two Africa-West Indies (slave) trips.
Wrecked 28th September 1802 on west coast of Anglesey.
Approximate position: 53° 9N, 4°27W.
Captain Carroll and crew saved.

Young William left from Liverpool on 31 November 1801 to the Bight of Biafra and Gulf of Guinea islands. She left Africa on 5 May 1802, and arrived at Kingston, Jamaica, on 21 June, where she disembarked 346 slaves. At some point James Pierce Carroll replaced Bennett as master. She left Jamaica on 28 July 1802. Of her crew of 43, 13 had died during the voyage. On her return to Liverpool, she was wrecked near Holyhead.

From Lancaster Gazette, Saturday 02 October 1802.
The Young William, from Jamaica, for this port [Liverpool], is on shore at Malltraeth, off Holyhead.
Lloyd's List adds: Part of the Cargo is expected to be saved.

Postscript There is a report of subsequent salvage of the Young William in 1839:
From Reading Mercury, Saturday 9 November 1839:
The Divers at Holyhead. - Last Saturday and Monday, Mr. Dean [John Deane], of the cutter Lalla Rookh [ON 7536, cutter or smack 34 tons, oak, built Isle of Wight, reg. London 1838; name of a princess in a 1817 poem by Thomas Moore about India, with some mention of divers], with the divers under his command, were successful in recovering ten great guns, and other articles, in seven fathoms water, a few miles to the S.E. of the South Stack Lighthouse. The said property had been from the Young William, Guineaman, wrecked on her passage to Liverpool in the year 1804[sic].

Comment Malltraeth is a bay and beach running north from Llanddwyn Island. It is about 13 miles at 132° [approximately SE] from South Stack Lighthouse. There are two known wrecks here - the Watkin F Nisbet (a Great Lakes steel steamship lost in 1940, charted in shallow water) and the Greek brig Athena (lost in 1852 and presumed to be the wooden wreckage embedded in the beach). There is no record of the location of the wreck of the Young William - which should be in deeper water [12m at LW] - perhaps near the Kimya (wrecked 1991) which is charted in 12m. Another possibility is that the crew aboard the Young William threw the guns overboard to lighten the ship, so she would be driven higher up the beach.

Further diving exploits in 1839:

From Chester Chronicle, Friday 11 October 1839:
On Monday the 7th inst.[October] Mr. Dean, the diver, visited the Skerries with his diving apparatus. Several vessels, some with valuable cargoes, have been wrecked on the island within the recollection of several persons living. He descended in eight fathoms water, and remained below for three hours, and succeeded in recovering about a ton and a half of iron. His chief object was a great quantity of copper and lead, reported to have formed part of the Cargo of one the vessels wrecked. But the strong current prevailing during the spring tides prevented a trial being made at that spot. Next neap tides, weather permitting, another and, it is hoped, a more successful attempt will be made.
Addendum The above report [9 November 1839 about salvage of Young William] by Dean states that: The above spirited individual succeeded in raising about three tons of lead at the Skerries, since our last report of their visit to that place.