The 22-year-old male was with work colleagues from the Lake District aboard a chartered yacht moored overnight on the River Medina when the fit occurred at just before 08:40.
Once the lifeboat was on scene, lifeboat crew member Peter Murphy-Latham went aboard the yacht to discover the man had suffered a diabetic fit because of a sugar imbalance. The young sailor was immediately given a glucose gel carried on the lifeboat, to add to the sugar given by the yacht crew.
Once in a stable condition, the volunteer lifeboat crew transferred the casualty to The Folly Inn where he was checked over by paramedics from the Isle of Wight Ambulance Service.
Thankfully, the 22-year-old did not require any further treatment and was therefore returned to the yacht by the lifeboat.
The lifeboat was rehoused at 09:45.