The jet nozzle at the rear of a personal watercraft (PWC) is the part responsible for the most severe internal injuries. This nozzle expels a high-pressure stream of water that propels the craft forward, and when a rider or passenger falls off and their body passes near it, that water can forcefully enter the rectum or vagina, causing life-threatening damage to pelvic organs. These injuries are sometimes called “blowout” injuries, and they can require emergency surgery.
How the Jet Nozzle Causes Internal Injuries
A PWC moves by sucking in water and shooting it out through a jet nozzle at the back of the craft. When someone falls off, especially from the rear passenger seat, their body can pass directly through or near this pressurized water stream while still airborne. If the jet stream contacts the perineal area (the region between the legs), water is forced into the rectal or vaginal opening at high pressure. The result is severe internal tearing, organ perforation, and contamination of the abdominal cavity.
The injuries fall into two categories. The first is barotrauma from the jet stream itself, where pressurized water enters a body cavity while the person is still in the air after being ejected. The second is blunt trauma when the person hits the water surface with their legs apart in a sitting position, which can also damage the anorectal and vaginal areas on impact. Of the two, jet stream injuries tend to be far more dangerous because the water pressure can tear through multiple layers of tissue and reach deep into the pelvic and abdominal cavities.
Why Passengers Face Greater Risk
In reported cases of these injuries, all victims have been passengers rather than drivers. The reason is positioning: passengers sit directly in front of the jet nozzle at the rear of the craft, so when they’re thrown off backward, their body travels through the path of the water stream. Drivers, by contrast, sit farther forward and are typically attached to an engine cut-off lanyard (sometimes called a “dead man’s switch”) that shuts down the engine immediately if they fall off. Once the engine stops, the jet nozzle stops pushing water.
Passengers rarely have access to a similar kill switch. If the driver falls and the lanyard cuts the engine, the passenger may still be ejected by momentum but at least the jet stream stops. If the passenger falls independently while the driver maintains control, the jet remains active. Some safety advocates have suggested giving passengers their own cut-off device, which could prevent the most dangerous jet stream injuries.
The Severity of These Injuries
The internal damage from a jet nozzle injury is extensive. In documented cases, victims have suffered full-thickness perforation of the rectal wall, meaning the water tore completely through the tissue. One case involved a laceration 5 centimeters deep in the perianal wall that broke through the external anal sphincter. Another patient had a torn anterior rectal wall extending from deep inside the abdomen down to the lower rectum, with contaminated fluid spreading through the abdominal cavity and free air visible on imaging, both signs of a ruptured organ.
A review of nine PWC-related anorectal injury cases found that four involved intraperitoneal damage, meaning the injury reached beyond the rectum into the abdominal cavity itself. In some of those cases, the damage extended as far as the sigmoid colon. One particularly concerning finding: the pressurized water can cause multiple, disconnected injuries along the intestinal tract. Rather than a single continuous tear, the force of the water creates separate perforations at different points, making the damage harder to find and repair.
For women, the risk includes vaginal injury in addition to rectal trauma. Clinicians treating these cases perform vaginal examinations specifically to check whether rectal lacerations have created a communication (a connected wound) between the rectum and vagina.
What Treatment Looks Like
These injuries require emergency surgery. The specific procedures depend on where and how badly the tissue is torn, but they commonly involve direct repair of perforations and creation of a temporary colostomy, where the bowel is diverted to an opening in the abdomen to allow the damaged rectum to heal without exposure to stool. In more severe cases, surgeons may need to remove a section of bowel entirely.
When the anal sphincter is ruptured, surgeons attempt to suture the muscle fibers back together to preserve the patient’s ability to control bowel function. Dead space in the wound is closed to reduce infection risk. Recovery is long, and patients may live with a temporary colostomy for weeks or months before a reversal procedure restores normal bowel function. The injuries also carry significant risk of infection, since rectal perforation allows fecal matter to leak into the abdominal cavity.
Reducing the Risk
The simplest protective measure is wearing a wetsuit or thick neoprene bottoms while riding a PWC, particularly as a passenger. While this won’t eliminate the risk entirely, it provides a physical barrier. Avoiding loose-fitting swimwear, especially shorts or bikini bottoms, reduces the chance of water entering a body opening on impact.
Passengers should sit as close to the driver as possible and hold on firmly to reduce the chance of being thrown backward toward the jet nozzle. Some newer PWC models have redesigned rear sections to deflect or diffuse the water stream, but the fundamental risk remains on any craft with an exposed rear jet. If you’re riding as a passenger, ask the driver to attach the engine cut-off lanyard to their wrist or life jacket so the engine shuts down the moment either of you is ejected. Keeping speeds moderate, especially with a passenger aboard, also reduces both the force of the water stream and the likelihood of ejection in the first place.