A woman and two children have been taken to hospital with suspected carbon monoxide poisoning from the same lake where a mother and daughter died last week in similar circumstances.
It is believed the family became ill on Windermere in Cumbria after leaving their boat engine running with the canopy closed. They managed to raise the alarm themselves by calling police who then rang the coastguard at about 7.30pm on Saturday.
North West Ambulance Service said the woman and both children on board were conscious and alert as they were taken to Lancaster Royal Infirmary. All three were later discharged after precautionary checks.
A spokeswoman for Liverpool Coastguard said lake wardens found the Bayliner cabin cruiser at a mooring with two adults and two children on board. The family, who had borrowed the boat from a friend, was transferred to a waiting ambulance.
The incident came just five days after the deaths of Kelly Webster, 36, and her daughter, Lauren Thornton, 10, from suspected carbon monoxide poisoning while on a boating holiday.
The pair, from Leyland, Lancashire, were treated by paramedics and airlifted to Lancaster Royal Infirmary where they died. Miss Webster's partner, Matthew Eteson, 39, the boat's owner, was released from hospital the following day after he received treatment.
Detectives are investigating whether the non-suspicious deaths were caused by a faulty generator on the Bayliner cruiser.
Cumbria Constabulary is continuing to advise lake users to ensure they follow appropriate safety advice before embarking on a trip to the Lake District and consult with the lake wardens' office if they have any doubts or require further advice.
Mark Roach, from Cumbria Fire & Rescue Service, said: "Please remember carbon monoxide is a poisonous gas given off by all appliances burning fossil fuels such as gas, coal, wood or oil, if they're not working properly or in an enclosed space.
"Incidents can prove fatal and even low levels can cause lasting damage to your health. Always follow instructions when using gas appliances and other items such as camping stoves, lights and even barbecues. Carbon monoxide has no taste, smell or colour. We strongly recommend that you fit an audible carbon monoxide alarm in your home and take one on holiday."