something "shook a screw loose"

[PeaceMaker]

Hi guys,

please what does it mean if something "shook a screw loose"? My guess is it means that something started the bad mood among the people, but I'm not sure.

Example:

(from some blog about sailing) Because the engine was having a hard time pushing through the troubled waters, the guys put up a reefed headsail. They turned to port to catch the wind and the boat took off. They even cut the engine to conserve fuel and the boat was doing over 7 knots! They knew they would have to tack to make it back to our original track to Bimini, but thought we would be out of the powerful hold of the Gulfstream and in the lee of the islands. It was a much smoother ride, but still bumpy as hell. The davit strut/stabilizer shook a screw loose and the dinghy came swinging into the boat. Sara was able to take the wheel while the guys rigged a line and fender to hold it back. It was time to tack and guess what? The Gulfstream still had us in its grip and the seas were as rough as ever.

thank you in advance for clarification.

[Milanya]

[PeaceMaker]

Great, thanks Milanya!