Both Lerwick and Aith lifeboats were dispatched over the weekend.
The Lerwick lifeboat was scrambled yesterday when the Norwegian yacht Osiris began taking in water south of Sumburgh.
The vessel was said to be coping well, but the lifeboat was sent to escort her to Grutness.
It followed an incident on Saturday morning when another Norwegian vessel, Exodus, sought assistance.
Her two-man crew had made themselves known to Shetland Coastguard on Friday night after her propeller became caught in a net while out near the Clair oil field.
The yacht, which was believed to have set off from Faroe, continued on her way.
But shortly after 8am on Saturday the lifeboat was sent from Aith to tow her in to Scalloway.
The net in the propeller together with the morning’s calm conditions meant the Exodus could make little progress without assistance.
Meanwhile, an injured oil worker was airlifted from the Transocean Prospect 116 miles south east of Sumburgh yesterday before being transported to hospital for treatment.
Poor visibility meant he had to be brought back to Sumburgh rather than the Clickimin landing site in Lerwick.