Modular Docking Systems

Piecing together the choices for modular polyethylene docks.

February 3, 2011

So much of boating revolves around hanging out at the dock that it’s no wonder many boat owners are looking for ways to enhance their private moorings. Boating looked into modular floating docks and discovered a variety of drive-on dry docking for all types of boats from PWC to runabouts and fish boats 25 feet or more in length. They are easy to assemble and install — many can be built in a day to secure your boat.

These lightweight, polyethylene docks offer boaters tremendous benefits. In areas of fluctuating water levels, they can be moved to meet changing conditions. Many offer dry-storage solutions in the form of drive-on, slide-off boat or PWC stations. They don’t rot or rust, and they don’t damage easily from impact. In fact, the roto-molded material is forgiving on gelcoat.

While early models were offered only in an industrial look, new models are molded to simulate planks or brick pavers, adding a sense of style. And to make it all the more inviting, in some areas, such as where docks are normally removed for winter and considered temporary, permits are often not required for installation.


More boaters are choosing polyethylene docks partly because the choices are so broad. We asked for input from manufacturers and installers on solutions to the modular dock puzzle.

Big Pieces or Small?
The key to understanding modular docks is knowing how they’re assembled. Most systems are made of individual sections ranging from 20-inch cubes to module dimensions of three to five feet. They butt together at their ends, along their edges or in any combination, creating great flexibility for unusual docking situations.

“It’s like a Lego kit,” says David Rueckert, founder of SportPort. “We can make pier docks, T-docks and drive-on docks in all shapes and sizes.” Larger modules are often favored by installers, while homeowners may choose smaller sections for easy handling.


| |SportPort docks use larger modules with keel tracks and piling holes molded in.|

While most modular docks are roto-molded in set sizes, AccuDock cuts sheets of plastic, welds them into a box, fills the box with foam and adds a stiff aluminum frame around the perimeter.

“They’re a little soft under your feet because they’re built of plastic and foam, but you get that same stable feel as with a concrete dock,” says Charlie Everette, who oversees AccuDock installations for Broward Piling in Pompano Beach, Florida. Everette also sells SportPort products, noting that they are lighter and stiffer than most poly docks.


Cube docks take the modular docking concept to the opposite extreme — each section is roughly a 20-inch square. More connections can bring advantages. For starters, if one cube is damaged, it isn’t a big deal for overall dock flotation or replacement cost.

Plus, all those connections give a bit, allowing them to flex with the waves. Flexibility is good but only to a point. Without solid connections, they are difficult to walk on because individual cubes sink underfoot.

Piecing It All Together
Each dock brand offers different and often patented connections, and manufacturers are naturally bullish on their own designs. To flex or not to flex is often the question.


Smaller modules are inherently more flexible, but EZ Dock uses rubber “dog bones” in matching sockets to draw dock seams tight. The rubber connectors let them flex in wakes and waves. By contrast, Shoremaster spans each joint with one-piece polyethylene strips, betting on rigidity for longevity.

Dwight Rajdal of Marine Dock and Lift in Center City, minnesota, says flexibility and rigidity have different benefits. He sees advantages to Shoremaster’s rigidity in less turbulent waters but says the flexible connections of EZ Dock or Candock can be better in ice and waves.

It’s best to drive around and see what others use. Get permission to walk on the various styles for a feel underfoot.

| |EZ Dock connects larger modules with flexible dogbone fasteners. “Planks” molded in give the dock a more traditional look.|

Keeping Everything in Place
Most docks are anchored with pilings or, alternatively, 4-by-4s or 4-by- 6s; 2-inch-diameter Schedule 40 galvanized fence posts work well too. Depending on bottom structure, you may need to jet them in with pressurized water. In deep water or rock bottoms, anchors in the water and onshore-cabled to the dock hold the position. The beauty of these systems is the flexibility in running current or changing water levels. The cables can always be lengthened or shortened.

Dry-Dock Mooring
Perhaps the most unusual feature and benefit of floating docks are their drive-on mooring solutions for boats from PWC to 30-footers. As in any docking situation, it takes a bit of practice to get the approach speed correct, but we tested drive-on capabilities of all these brands and found them to offer secure dry storage that’s easy to master in just two or three attempts. Some docks require installation of a winch for a single individual to relaunch larger boats, but for boats under 20 feet, two average teenagers or an adult could lean into the bow and slide the boat back. Personal watercraft are even easier.

Yet Another Advantage
Permitting agencies range from the U.S. Army Corps of Engineers to state, county or municipal government, and lake or even homeowners’ associations. In Florida, most floating drive-on docks are considered, by law, temporary, and therefore don’t need permits. Dock size and complexity and how permanently they are anchored to the bottom all weigh into permitting requirements.

Wherever you live, modular docks offer benefits worth looking into. Wood docks won’t be going away anytime soon — but it’s always nice to have choices.

| |Candock cubes are fitted with keel channels. Use more for longer boats. “Planks” molded in give the dock a more traditional look.|

Add Some Accessories
Available accessories vary noticeably among manufacturers. Look at diving boards, slides, ladders, canopies, storage and seating options when choosing a system. Kayak and canoe docking accessories have become popular too.

Fenders, cleats and other accessories all attach differently — for example, Candock’s standard cleats mount low, on the dock’s side. This gives an uncluttered appearance and won’t catch toes but also might be harder to use.

| |ShoreMaster’s dock sections feature a stylish brick paver finish for a more permanent finished appearance.|

How utilities run along the dock also varies. EZ Dock, for instance, offers narrow floating modules with two hollow tubes, keeping power and water runs hidden and protected while increasing the dock’s width by 20 inches.

The Players


EZ Dock




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