Some dogs are natural swimmers. Others, like Ernest Von Zell’s Scottish terrier, are not. Scotties not only have short legs and barrel-shaped bodies, but they have a bowlegged stride that works fine on land, but as Von Zell explains, has a defeating effect in water.

So when the dog fell into a swimming pool recently, Von Zell, now a youthful 79 years old, had to make a sort of rescue, which, as he tells it, involved jumping into the pool in his seersucker suit and bow tie and dragging the dog to safety.

After the close call, Von Zell went looking for a pet life jacket, but every one he found had a caution label indicating it should not be used for small dogs with small legs. Put differently, they were for the kind of dogs that could probably swim.

Dogs with smaller extremities have less control in the water, Von Zell explained. “They’ll float. But so will a log.”

What the smaller dogs needed was something to keep them from rolling over. To Von Zell it seemed obvious, but there was nothing like it on the market.

So he invented a life jacket for small dogs, using a horseshoe-shaped ring of Ethafoam — think pool noodles — covered in fluorescent yellow ripstop nylon with a reflective strip. The foam would go around the dog’s chest, extending down either flank like a pair of pontoons — the nylon covering forming a vest around the dog with holes for the legs and head. For the owner there was a handle on the back, so the dog could be picked up like a suitcase — or a lobster buoy — and a D-ring on the front for a leash.

Canine Swim Safe, as Von Zell named it, would allow the dog to run in and out of the water like an amphibious vehicle.

“When they’re put in the water, they immediately know they don’t have to move their legs around to stay afloat,” he said. “That dog could be out there 10 hours and it won’t drown. It could fall asleep. It won’t drown.”

The vest is also ideal for hydrotherapy, Von Zell said, because the dog feels secure enough in the enclosure that it can get the benefits of low-impact exercise without panicking and potentially re-injuring itself.

Von Zell is not a serial inventor, but he has come up with several safety-related devices over the years. One of his earlier inventions was a protective vest for equestrians — the riders, not the horses. He named it the Robin Body Protector, after a friend who was injured after being thrown from a horse.

The idea of the vest, which, incidentally, resembled a life jacket, was to spread the force of impact using dense foam padding. Von Zell claims he sold 10,000 Robin Body Protectors, but he didn’t file a patent, and as he tells it, the design was “ripped off by the Canadians.”

Before long all the Olympic riders were wearing protective vests. Not Robin Body Protectors, but basically the same idea.

“Without belaboring it too much, they were very successful,” he said, dryly.

Von Zell made sure to patent the Canine Swim Safe, and a pared-down version called the Heads Up Flotation Collar, and for a time they were manufactured at Creative Apparel in Belfast. That relationship soured and Von Zell stopped mass-producing the vests, though he still offers them on his Web site for $89.95. If he can find someone to manufacture and market the vests, Von Zell said he hopes to get that figure down to between $49.95 and $59.95.

“It would be a gift to them [the manufacturer], because it sells itself,” he said. “Nobody has this.”

Von Zell said he was currently working on a bilateral flotation device for a horse.

For more information on Canine Swim Safe vests, contact Von Zell at 338-4500, or visit canineswimsafe.com