There is a lot of sizzle to the 34th America’s Cup this summer on San Francisco Bay.

For the first time in America’s Cup history, the event will be sailed inshore rather than far offshore with the San Francisco Bay venue guaranteed to be the best ever when it comes to spectator viewing.

And the 72-foot catamarans add elements and speed and excitement never before seen in the 162-year-old event.

But is there any substance to this America’s Cup, which is so drastically different from the traditional America’s Cup that it almost seems like a totally different event?

The total fleet for the event is four boats. Only two of the three challengers are ready to race this weekend with the beginning of the challenger trials. There will be no defender trials.

But there is controversy. There is always controversy in the America’s Cup. But this one takes the tradition a giant step beyond where we’ve been before.

On the eve of the July 4 Opening Ceremonies – which drew large crowds to San Francisco’s Pier 27/29 America’s Cup Park – race director Iain Murray threatened to ask the U.S. Coast Guard to pull the racing permit for San Francisco Bay if two challengers didn’t agree to 37 safety requirements.

The requirements were unilaterally imposed by the organizing committee after the May death of crewman Andrew “Bart” Simpson in an accident on San Francisco Bay that destroyed the entry of Sweden’s Artemis team.

If the Coast Guard pulled the permit, the event would be scuttled because the catamarans can’t race on San Francisco Bay without Coast Guard approval.

Meantime, the New Zealand and Italian challengers, who are scheduled to race Sunday in the first race of the Louis Vuitton Cup challenger trials, are going ahead with their protest of the changes — claiming they give the defending Oracle team an advantage.

The main dispute focuses on changes required to the rudder elevators – hydrofoils at the bottom of the rudders that allow both hulls to raise out of the water while on high-speed runs off the wind.

Emirates Team New Zealand and Italy’s Luna Rossa challengers are taking the issue to the international jury as soon as Monday and threatening court action. The Italians, meanwhile, say they might not race Sunday – further reducing an already limited schedule since the Swedes aren’t expected to be race-ready with their new boat until next month.

The spectacle of 72-foot catamarans flying around San Diego Bay could be reduced to a weaiting game.

Certainly, this is not what San Francisco expected when it signed on to back the 34th America’s Cup.

The defending Oracle syndicate led by Larry Ellison, team boss Russell Coutts and on-the-water skipper James Spithill hoped the entries would reach double figures when the rule was first established for the 72-foot catamarans for the 2013 America’s Cup.

Indeed, the America’s Cup World Series contested in 45-foot catamarans, which included a 2011 stop on San Diego Bay, drew nine boats representing eight teams.

But only four teams reached San Francisco. In contrast, the 1995 America’s Cup, the last of three raced out of San Diego, drew seven challengers and three defenders. The 1992 America’s Cup in San Diego, drew eight challengers and two defenders.

And whereas the last two America’s Cups sailed in San Diego included defense trials, the Oracle defenders won’t be sailing until the best nine-of-17 actual America’s Cup starts on Sept. 7.

There is no question that the 72-foot catamarans are spectacular – although many in sailing believe the risk of major accident goes beyond the reward. At a true wind speed of 18 knots, the AC-72 catamaran is capable of reaching speed of 40 mph – essentially flying on the tiny hydrofoils in question.

“What’s so amazing about this boat is that it’s suspended on these tiny pieces of engineered carbon-fiber,” said Spithill. “that’s why these boats are so cutting-edge technologically. We’re pushing them right to the limit.”

A lot of sizzle.

But any substance?