Goofs

In the last scene as Nick is reviving Sara, and Sherman jumps out of the water onto the boat, Sherman is dry and not a single drop of water is visible.

In the opening scene, the girl's top pulls off but then reattaches every time she gets pushed out of the water.

The cabin is set on fire and the sheriff is killed by the shark, but as Nick leaves there is no trace of a fire having even taken place.

The first scene with Beth in it shows her getting a tattoo which would prohibit her from swimming or being submerged in water for an extended period of time without severe pain and infection.

The shark tank that Sara is in has floats to keep it upright on the surface. However, when the tank is cut loose, it sinks to the bottom of the lake.

Lily pads don't grow in salt water lakes.

There are saltwater water lilies aswell as fresh water lily pads.

They obviously used a green filter to film underwater to make the clear blue freshwater look like green saltwater. This was noticeable by the fact that Sara's blue bikini was a very bright green in every underwater shot of her and it was light blue when she was out of the water.

Sheriff's badge and name tag should be reversed as they are on the wrong side of his uniform (Badge on Left, Name Tag on Right).

Nick's reaction to Sara offering to let him drive the boat on the way to the island suggested that he didn't have much experience with boats. Yet to pull a water skier requires great experience and skill with a boat, both to keep the skier safe and give them a good ride. Plus, in the bayou area, a boater would need incredible familiarity with the waterways to avoid getting lost, trespassing, hitting sandbars or submerged logs, or entering into awkward turns and other maneuvers that would risk the skier's safety.

As Sheriff Greg Sabin drops into the water after being lit on fire, you can see the stunt double's wig come off.

The sheriff had no trouble radioing to the mainland from the island house, yet Sara didn't question Dennis's statement that they would have to wait to "catch a signal" on the way to the marina to order a medevac. No one even raised the issue of why they couldn't try the radio on Dennis's boat right then and there to get help.

The fire Nick started in the boat shed apparently put itself out, without spreading to the other gas cans or myriad of flammable junk laying around; it also left no mark on the floor or the area where the sheriff was standing when he went up.

It is odd the island home has no means of communication. If they could not have a phone line run out, certainly the family would keep a shortwave radio or satellite phone.