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About this time disease and hunger took hold within the city. It became evident that the town needed to be relieved. William gave that task to Major-General Percy Kirke, who decided to first explore the mouth of River Foyle to find out whether ships could get through to Derry. He sent the engineer Jacob Richards, son of Solomon Richards, mentioned earlier, with the small (sixth-rate) frigate HMS "Greyhound" and two ketches. They sailed from Hoylake on 13 May and explored the mouth of River Foyle on 8 June. However, "Greyhound" ran aground near Fort Culmore and was damaged by cannon shot before she got afloat, escaped and after some makeshift repairs limped back to Greenock in Scotland to refit. Observations and information obtained from the inhabitants confirmed that the besiegers had placed a boom across the river. Indeed, on 3 June, the besiegers, led by de Pointis, had placed a boom across the River Foyle about halfway between Derry and Culmore.