NYCFerry had to charter an additional boat to take riders to the beach this weekend. Here is a line of people waiting to leave the peninsula after a day at the beach. View Full Caption DNAinfo/Katie Honan

ROCKAWAY PARK — The summer's first heat wave tested the limits of the city's new ferry service, as it tried to adapt to "extraordinary" ridership — but still left many riders stranded on the docks.

More than 8,000 passengers rode the NYC Ferry from Wall Street to Rockaway, with a stop in Sunset Park, on Saturday and Sunday, an official at NYC Ferry said.

By comparison, 6,000 riders took the ferry during the three-day Memorial Day weekend.

To meet the demand, officials made adjustments in "real time," a spokeswoman said, adding a third boat to the beach all weekend.

But it wasn't enough to take everyone who wanted a respite from the city's heat to Rockaway Beach — where there was a cool breeze and clear ocean temperatures at a refreshing 60 degrees.

As boats filled up in Manhattan, they skipped the stop at Brooklyn-Army Terminal, riders said.

"No one is able to get to the Rockaways from Sunset Park today," Kathryn McGrath tweeted. "The ferries are full from Wall St. @NYCferry didn't bother telling anyone tho."

"Note that the @NYCferry is delayed, over capacity, and not bothering with niceties today. So it's a good day to take the subway," rider Tatiana tweeted.

"We are aware of the long lines during the very busiest times and worked hard to minimize customers’ wait," a NYC Ferry spokeswoman told DNAinfo in an email.

They added coach buses to work alongside the smaller shuttle bus that take passengers from various stops on the Rockaway peninsula. And they've also chartered two additional boats, each with a capacity of 400 people, to meet the demand to Governors Island.

"Chartering vessels to meet demand is a standard part of ferry operations, and is something we will continue to utilize, especially as the 12 remaining NYC Ferry vessels are being completed," a spokeswoman for the ferry service wrote in an email.

Since launching May 1 with much fanfare, NYC Ferry has made adjustments to many of the routes — yet there has still been issues with delayed or canceled boats and a struggle to meet ridership demands.

Mayor Bill de Blasio, while touting the June 1 launch of the South Brooklyn ferry route, said there is a possibility of building bigger boats.

The city would have to examine ridership this summer before making a decision, he said.

The $2.75 one-way fare is subsidized by the city. Use of the bike racks cost $1 extra.