Trick "tubes" than spin 360 degrees, alien spacecraft, blow-up mountains for climbing, family-sized islands, towable bananas that seat up to 12 – the black tube pulled behind a boat with a simple rope is so 20th Century.

Today's inflatable boat accessories are big, bold, colorful and crazy – and they seem to get more so every year. They render the simple inner tube almost quaint.

Need an example? SportsStuff's "Nuclear Explosion," a six-foot diameter bubble, allows its rider to walk on water – no boat required – much like a hamster on a wheel, but actually going somewhere (sort of).

RAVE Sports, best known for its trampolines and floating decks, has an inflatable Cobra with prone and upright riding positions. Aviva Sports sells a 14-foot inflatable "Iceberg" for climbing, and a line of towables that includes a Y-shaped tube called the "F-16."

SPORTSSTUFFThe 14-foot-tall Iceberg (at almost $6,000) is pretty cool.Even in a down economy, water toy retailers are doing remarkably well. People who are unwilling or unable to trade up on a newer boat are instead investing in the latest wave of boat accessories – including ever-larger toys, according to retailers and manufacturers.

"They may not be buying a new boat but to satisfy the urge they are buying a new tube or ski or wakeboard," says Grace Robinson, president of Mobileation, Inc., an on-line retailer based in Arizona.

That's good news for the after-market accessory industry. Tubes and other towables make up 40 percent of the water sports market, says Larry Meddock, executive director of the Water Sports Industry Association.

"It is huge," he says. "It is very popular and profitable."

EGALITARIAN APPEAL

Two categories are especially strong: large platforms such as trampolines and towables designed for two riders.

Unlike wake boarding or water skiing, riding a towable takes tolerance rather than skill, the ability to hold on and handle some splash up the nose. People who would not dream of grabbing a ski rope will willingly sit, kneel or even stand on something filled with air that buffers them a bit from the water's impact.

MOBILEATION.COMWhy ride one at a time when four-aboard is so much more fun? Some toys can hold many riders. "If it is mom and dad and Uncle John and Aunt Suzie and they have no physicality and are non-athletic in nature, they can get in the tube and you can drag them around the lake," Meddock says. "If you are sitting in a tube, you can go forever if there is enough air underneath. The designs that allow you to sit with cushion, it is a nice way to go sightseeing.

"Once you get into a prone position and are lying down you need material under you so your chest doesn't get beat to death," he says. "If you start laughing you can ingest a whole lot of water and start choking but you can control the tube a bitter better. They all have different benefits to them."

Alan Petersen, a SportStuff customer service representative, got to help test the company's new 2009 products last year. A fan of the two-rider options, Petersen says he laughed. A lot.

"To me, a two-person is a little more challenging, especially when you get close to dumping over the tube," Petersen says. "I felt like I was in a comedy club. You totally forget about everything else."

SUPERSIZED INSTINCTS

The inflatable accessory market has offerings at many price points. A tow-behind tube can cost less than $100. A 14-foot iceberg, on the other hand, runs nearly $6,000. The bigger, more expensive floaters typically are targeted for the commercial market, but individual consumers just can't help themselves.

SPORTSSTUFFEver larger toys are becoming extremely common.For some, it's simply one more way to compete, says Geoffrey Godbey, professor emeritus of recreation and parks at Pennsylvania State University.

"If bigger is better for watercraft, than it makes sense that bigger is better for the toys, too," says Godbey, who is president of Next Consulting and speaks widely on the future of recreation and tourism. "It seems to replicate that syndrome pretty perfectly."

"Buying expensive isn't the point. You have to show you have more than you need," he says. "This is tribal and goes back a long way."

The trends also speak to the human desire for community. Robinson, who launched Mobileation as an online retailer in 1996, predicts more growth in group inflatables, including platforms, moonwalks, catapults and other designs that give families and friends together-time on the water. If buying a boat or keeping one is too expensive, investing in a floating island may still be in reach, she says.

"I think we are going to see more contraptions that allow you to play in ways like that," Robinson says.

Islands with built-in coolers and other extras for groups that want to tube down a river together are a likely next step, says industry spokesman Meddock.

SAFETY FIRST

All inflatable accessories carry some risk; the Coast Guard recommends riders wear approved life vests, and the boat driver carry a cell phone, flashlight and signal flare kit. This summer alone has seen deaths in Texas, Mississippi, Florida and Nebraska – all involving accidents with tube riders pulled behind boats.

One 12-year-old boy Texas was killed when he fell out of a tube and the boat pulling it struck him. One Nebraska woman was killed and another seriously injured when their tube crashed into a dock. A woman in Florida died when her tube smashed into a tree.

SPORTSSTUFFExperts say most accidents these days have more to do with the rider than the design of the toy.The risks rise with extra riders, alcohol and inattention. "When people get hurt is typically out of boredom, and if alcohol gets (into) the mix," Meddock says. "The boat driver decides to eject them out of the tube, or one rider wants to scare a companion, and asks for a sharper turn."

With more than one rider, bonking heads can cause serious injuries. Meddock knows first hand – a few years ago, his 13-year-old daughter landed in an emergency room with a concussion after smacking heads with a sibling. Meddock was driving the boat.

The typical accident, he says, "has nothing to do with the design of the tube and everything to do with the stupidity of the driver."

So-called "kite tubes" – towables that lifted their passengers into the air – were an exception. The Consumer Product Safety Commission in June of 2006 issued warnings after multiple injuries and some deaths, and manufacturers recalled the products the following month.

Tim Smalley, boat and water safety specialist at the Minnesota Department of Natural Resources, remembers seeing the rigs at a boat show the year they hit the market.

"I thought, 'Those are going to be trouble,'" he says.

NEXT GENERATION

With flight no longer an option, innovations in inflatable pull-behinds and stationary floaters are more grounded. Manufacturers each year come out with something new to meet the demand for bigger, faster and cooler toys.

SportStuff, for example, in 2009 introduced its new "Doables" line, which gives riders more steering and skipping control, and a booster ball that lifts the tow rope out of the water, improving fuel efficiency, says Mike Pleiss, the company's art director.

"The director of research and development comes out with something new every year," Pleiss says.

The new "Lulu" has spinning and steering fins; "Mabel" offers two tow points so riders can sit as if on a sofa or stand, chariot style. SportStuff uses lots of red, yellow, black and white for branding and visibility on the water. "Those are water sports safety colors," Pleiss says. "By making it big and bright we want it to be seen."

But that doesn't mean technology is out of the picture.

The recreation industry is trying to tap into the preference of teens and other tech-savvy consumers for bringing their music with them outdoors. It is only a matter of time before water toys have i-Pod docking stations – Meddock has seen one prototype already.

As any boater knows, though, water and electronics are a tricky mix.

"We have seen some helmets come out so someone in boat can be communicating with person on the tow line," Meddock says. "But they haven't figured out how to give that guy (the tube rider) a microphone."

SPORTSSTUFFNothing beats a trampoline for on-the-water thrills.