Possible Clues:

• The old craft got to Ireland down at last (6)
• Hull down in Ireland for the old ship
• Vessel at base in Irish town
• Had Noah's craft got to Ireland it would have been heavily loaded
• Noah's craft evidently has a heavy cargo as it gets there in 15 across
• Had Noah's vessel got too heavy a load when it got off the coast of Wicklow?
• Seems that Noah's vessel was overloaded when it got there in Ireland