Complex sentence: The "Tryal" took the "Arranzazu", an unarmed merchant ship three times her size carrying cargo of little use except for £5,000 in silver but badly damaged by storms, her guns were transferred to the prize vessel and she was allowed to sink.
Split into simpler sentences: The "Tryal" took the "Arranzazu", an unarmed merchant ship three times her size carrying cargo of little use except for £5,000 in silver. The Tryal had been badly damaged by storms, so her guns were transferred to the prize vessel and she was allowed to sink.