A shuttle system linking Cabrillo National Monument to the San Diego Convention Center — a route that would wind up and down port tidelands — is finally taking shape for the Unified Port of San Diego, thanks to a $625,000 federal transportation grant announced in December. The idea of the so-called Cabrillo Circulator Shuttle has been batted about for about 10 years, according to Ronald Powell, port director of corporate communications. Port officials plan for a five-shuttle fleet that would be capable of moving passengers about 12 miles along North Harbor Drive, stopping at Seaport Village, cruise ship terminals and other destinations, on the way to the San Diego Convention Center. “We have, for years, needed a downtown shuttle to bring people to the waterfront,” Powell said. “This will give us an opportunity to expose tourists [to the port tidelands] and we look forward to doing that.” Port officials are currently looking for private partnerships to sustain the shuttle after it’s initial five-year run. The Port District has up to three years to launch the program and will be working with port tenants to maintain the system to boost exposure for businesses in the future, according to Powell. About $125,000 of the grant will go toward signage along the routes, with added signage aboard the shuttles. About five natural gas, hybrid or biodiesel-fueled shuttles would cost roughly $100,000 each, according to estimates. The shuttle should help ease transportation snarls along the destination points up and down Harbor Drive, said Steven Johnson, the San Diego Convention Center Corporation’s vice president of public affairs. The San Diego Convention Center Corporation projects more than $20 million in tax revenue will be infused into the local economy over the next year as a result of 120 events that could draw about 800,000 people to the convention center, according to port officials.