The Littlehampton RNLI crew was called to investigate a floating lifejacket and a broken down jet ski in the space of four hours on Friday.
The first callout followed reports of a lifejacket floating in the River Arun, half a mile upstream of the A259 road bridge, at 4.17pm on Friday (July 6).
The Atlantic 85 lifeboat Renée Sherman proceeded up the river to the reported location, where the lifejacket was located.
During a search of the area, clothing was found on the east bank of the river and was taken aboard the lifeboat before the search continued towards Ford Marina.
The clothing was returned to its original position so that the Coastal Rescue Team could pinpoint their search area.
A Coastguard spokesman said the lifejacket was thought to have fallen off a boat and concluded it was a false alarm with good intent.
The lifeboat returned to the station at 5.22pm.
At 7.54pm, the crew launched for the second time following a call from a jet skier stating that his jet ski had broken down a quarter of a mile from the beach between Littlehampton Harbour and Climping.
On scene, the lifeboat crew rigged up a tow line to the jet ski and towed it and the skier back to Fisherman’s Quay in Littlehampton Harbour, where the Coastal Rescue Team were waiting to interview the jet skier.
The lifeboat returned to the station at 8:45pm where it was refuelled and made ready for service.