Marina Dock Age, September/October 2002

Where There are Boats There Must be Cars—But How Many?
by Ron Brazda

Is the amount of car parking at marinas and boat launching ramps meeting the demand? Is there any way to determine a reasonable ratio?

No such thing as a universal rule

A speaker at ICOMIA’s 2002 Marina Conference in Sydney, Australia, recommended that a committee coordinate surveys of marinas worldwide to establish ratios of car parking to slips and moorings. These guidelines would be useful to marina planners and developers, zoning and other government agencies involved in the permit process.

However, this is not as easy as it sounds. The difficulty, concedes Christopher Hallam, a Sydney-based engineer, is the wide range of variables affecting boat usage and parking demands. One needs to be able to compare marinas that share similar locations, boats, and boating activities.

Typically, trailered boats need larger spaces—more than double a normal parking space for a berthed boat. On the other hand, a marina may have both inwater and upland berthing for boats, increasing the need for parking spaces to accommodate slip users and their guests. Also, with marinas as mixed use developments, slip holders may find themselves in competition with restaurant patrons, retail shoppers, office workers, and tourists.

Of even more importance is having a grasp of anticipated use of the facility. Boats in wet slips and dry storage tend to have very limited use during normal weekdays (possibly 10 to 15 percent) during the boating season, and almost none (less than one percent) off-season. On normal weekends, marinas see a higher use (possibly in the 20 to 30 percent range depending on the weather). On extended holiday weekends, traffic is obviously higher (40 to 60 percent).

In its Code of Recommended Practice for the Construction and Operation of Marinas and Yacht harbours (Rev. 1992), The Yacht Harbour Association of the U.K. points out that if a marina caters mainly to transient vessels, i.e., yachts on passage, or if there are already adequate parking facilities available nearby, it’s possible to make a case for the reduction of parking spaces within the marina boundaries. On the other hand, if weekly hire boats are operated from the site (as is common on the U.K.’s inland waterways) two car spaces per boat normally will be required.

What studies show

There was a time, pre-1990s, when zoning codes commonly provided parking ratios of 1.5 or 2.0 parking spaces per slip. However, today there is a difference of opinion among countries about whether marinas really need so much parking space.  

In their definitive Small Boat Harbors and Marinas, 2nd Edition (2000), authors Bruce O.Tobiasson and Ronald C. Kollmeyer find that the current recommended ratio, based on increasingly accepted practice in the U.S., is to provide 0.6 to 0.8 parking spaces per berth. This ratio suffices year ‘round, except on major holidays such as the Fourth of July. Because peak marina use days generally coincide with work holidays or weekends when office and commercial parking space is idle, overflow parking at urban marinas can often be found in nearby parking garages or office lots. Away from urban areas, overflow parking at marinas and boat ramps is often accommodated in unused land storage areas.

From time to time, studies have been conducted in the United States to determine parking needs at marinas.

For example, a 1988/89 study by Neil Ross for the International Marina Institute (partially updated in the mid-1990s) verified that the number of parking spaces required for marinas with in-water slips, upland rack storage, and mixed-use amenities ranges from 0.6 to 0.8 per boat slip.

Another study on the north shore of Long Island and Connecticut was published as a paper for ASAE’s World Marina’91 Conference.

To determine parking demand under absolutely peak conditions, the survey took a cross section of 42 public rental marinas, yacht clubs, municipal marinas, and private condominium associations, in the heavily trafficked Long Island Sound between the hours of 2 p.m. and 4 p.m. on the Fourth of July. The survey was taken by photographing marina occupancy from a low-flying aircraft. Prior to the aerial study, telephone calls were made to the marina managers to verify the number of parking spaces and boat slips. It was assumed that each marina surveyed was 100 percent occupied. At mixed-use sites, all cars were assumed to be connected to marina users.

The average percentage of boats counted away from their slip at the time was 39 percent. To figure out the day’s peak demand, the total number of cars parked was divided into the total number of slips at the marina. It was determined that the average peak demand for parking space was .65 cars per slip.

However, the paper was quick to point out that the findings of a local survey are limited in their application and may not be adaptable for use in other places. There are so many variables, it is impossible to make projections.

It is therefore understandable why, when the ICOMIA Marinas Committee queried its members from more than 30 countries, it could find no national statistics for quantifying the number of parking spaces required for a marina. Continue »