King County Transit is looking beyond asphalt for transportation options in the coming years.

Harkening back to the days of the Mosquito Fleet, when hundreds of boats carried people as well as mail, merchandise and supplies around Puget Sound, King County Transit recently completed a study of the future potential for water taxis, passenger-only ferries and other vessels to help move people around.

Planners are quick to point out that waterborne transit could never replace cars, trucks, buses or van pools. Water taxis and passenger-only ferries would only augment land-based modes of transportation.

King County is studying this because county taxpayers likely would have to help pay for future waterborne transit, just as they currently subsidize the Elliott Bay water taxi. Waterborne transit frequently requires more financial help from taxpayers than buses, according to the study.

The exception is the Elliott Bay water taxi. Passengers on the water taxi pay about 30 percent of its operating costs while Metro bus riders contribute about 25 percent of the cost of running buses.

The study said the Elliott Bay water taxi could be run more cost-effectively however if King County made long-term investments in it. Under the current system, the water taxi operates on a year-to-year basis using borrowed docks.

For many years, the water taxi has used the dock at Seacrest Park as its West Seattle landing site. However the park is owned by the city, which has a policy of disallowing "nonpark uses" of park facilities.

A new dock for the water taxi has been envisioned south of Salty's on Alki restaurant at Pier 2, which is owned by the Port of Seattle. It's also at the city-owned street end of Bronson Way, just off Harbor Avenue. Moving the dock there would provide more parking too.

Another study recommendation was to have a vessel designed specifically as a water taxi meant to sail in Elliott Bay conditions. Currently the water taxi is a 70-foot monohull tour boat called Sightseer that can carry 149 passengers. The study recommended a boat designed specifically for Elliott Bay conditions that could carry 80 to 150 passengers at a maximum speed of 22 to 25 knots

The terminals on each side of the bay also should be set up for water taxis specifically, according to the study.

While the Elliott Bay water taxi runs east and west, King County's waterborne transit study also examined a potential north-south water taxi route across Elliott Bay, from West Seattle to North Bay between Magnolia and Queen Anne. It would sail from a dock near Harbor Avenue to Pier 90 by the Magnolia Bridge.

The Port of Seattle owns 57 acres adjacent to Piers 90 and 91, next to the Magnolia Bridge in an area planners call North Bay. That area used to be where imported cars were stored temporarily but shipping has changed in recent years so the Port of Seattle wants to sell the property.

Amgen, which claims to be the biggest biotechnological company in the world, already has a large facility at North Bay that employs 800 people. The company has permits to add twice as many more employees there. Planners speculate there's room for 10,000 more employees in research and development of high-tech industries as well as maritime businesses.

Port planners thought a good landing point for water taxis, whether they came from West Seattle or anywhere else, would be on the landward side of Pier 90, said Dan Burke, a Port planner working on the North Bay project.

The King County study also considered passenger-boat service on Lake Union, with smaller, 50-passenger boats running between the University of Washington and South Lake Union. Another idea was a boat route that would circulate around Lake Union, Portage Bay and the Ship Canal.

Other possible passenger routes were studied for Lake Washington. One would run between North Renton and Leschi, while another route could run between the University of Washington and Kirkland.

The study also looked at passenger-only service between Vashon Island and downtown.

A triangular route of passenger-only boats connecting Vashon, Southworth and downtown also was considered.

Planners didn't think any of the proposed routes would be profitable.

Another reason for the waterborne transit study is the impending replacement of the Alaskan Way Viaduct. Water taxis and passenger-only ferries could help move people while the downtown waterfront is a construction zone.

The county also is interested because water taxis and passenger-only ferries have proven to stimulate economic development, tourism and recreation.

Not all passengers are commuters either. Surveys of passengers have shown some people just love boats and will seek out water taxis and passenger-only ferries just for the appeal of riding them, according to the study.

The study included ideas for paying for more waterborne transit

As far as "farebox recovery" is concerned, the most lucrative waterborne service would be a triangular run connecting downtown to Vashon Island and Southworth. According to the study, passenger fares could pay for about 74 percent of operating costs.

Next best would be a Vashon-to-downtown run, but fares would pay only 39 percent of the cost.

The Elliott Bay water taxi is No. 3. Its passengers pay about 30 percent of the cost.

The most heavily subsidized route likely would be the one from West Seattle to Pier 90. Fares would cover only about 7 percent of costs, according to the study.

The study offered other suggestions for how to pay for new water taxis and passenger-only vessels. One idea was an increase in the sales tax.

Another suggestion was to conduct an initiative campaign asking voters in the region to tax themselves for new water taxi service. A similar idea would be to create a ferry district, which could collect ferry tax revenue from property tax.

The public also could be asked to approve an increase in the motor vehicle excise tax. The study suggested increasing the tax two-fifths of 1 percent.

There could be a sales and use tax of two-fifths of 1 percent that could go to an entity called a "public transportation benefit area."

Tim St. Clair can be reached at tstclair@robinsonnews.com or 932-0300.