A family of four is seriously counting their lucky stars — they spent 20 terrifying hours stranded at sea off the coast of Florida … and there are vivid pics and video of them right as rescuers swooped in.

The fam, spanning three generations — Dennis Woods, 70, his 90-year-old uncle Clarence, plus Cris Harding Sr., 42, and Cris Harding Jr., 18 — were seen desperately waving Tuesday morning, standing on top of their 25-foot catamaran — ironically named Money Well Wasted — when the Air Station Miami HC-144 Ocean Sentry crew finally spotted them.

The foursome set out at 9:30 AM the day before for Dennis’ birthday fishing trip … but by early afternoon, the catamaran started taking on water and flipped. According to the Coast Guard, they were reported missing by another family member Tuesday night.

Dennis’ sister Teresa told Fox 13 and Tampa Bay 28 they thought they weren’t gonna make it, and prayed all night. So when they were finally found the next morning — about 26 miles west of Clearwater — it felt like a full-on miracle … especially since the catamaran was almost completely submerged by then.