Guide: Building a floating dock

Everything you need to know for a first-class floater on any budget

By David ZimmerDavid Zimmer


Photo by Dockinabox

1 comment

At our cottage, we used to think crib docks were king, mostly because of a rich history of crib building on our waterway, inherited from the good old days before cottages were invented, when dock building meant dropping boxes made from tree trunks into the water and weighing them down with rocks. Now that’s a dock.

Floating docks were foreign to us, a newfangled rarity, reserved for wobbly marina finger docks and not to be trusted. Our crib docks, on the other hand, built by the previous owners to moor a commercial fishing tug and a fleet of rental boats, were huge. Massive. Solid. Immovable. Until one year, when the irresistible ice floes of spring breakup decided to take our Rocks of Gibraltar and — as easily as you might flick lint from a sweater — frogmarch them out into Georgian Bay toward…Destiny. Or Meaford, as the case may be.

So we rebuilt. I was but a stripling at the time, but for this wharf my older brothers pulled out all the stops, building a monster of a dock. The cribs were wider. The timbers more massive. The oversized decking, obtained from a nearby mill that supplied mining timbers, was held down with seven-inch nails. It was a veritable Colossus of Rhodes, this dock, and it wasn’t going anywhere. And it didn’t for quite a few years until, ironically, the waters of Georgian Bay did. By 2001, you needed a stepladder to climb out of a boat and onto the dock because the water at the business end — previously able to float a fixed-keel sailboat — was now less than a foot deep. Left high and dry, we started thinking seriously about floating docks.

Of all the different styles of docks that are available to cottagers, only one, the venerable floater, is versatile enough to make it the hands-down choice for the majority of folks with lakefront real estate. Floating docks work in most water depths, and can be configured to perform all sorts of cottage functions other than boat parking (think swimming, sunning, and snoring). They adjust themselves without effort to frequently fluctuating water levels, can be relocated or removed to avoid ice damage, and are a relatively benign environmental presence on your waterfront. Perhaps the niftiest thing about a floating dock is that it can be scaled to meet your personal needs, whether you want to tie up a single cedar-strip canoe and walk straight to shore or need a floating structure that can support a boathouse complete with a sauna, Munich-style biergarten, and a helicopter pad on top.

If you’re wondering whether a floater is right for the shoreline at your place, the first thing you have to ask is whether you’ve got enough water. Floating docks excel along deep-water shorelines where crib or pipe docks don’t have a leg to stand on, but extremely shallow conditions can leave them bouncing in the mud. Harold Blower, of Rose Point Contracting, has been building floating docks around Muskoka and Parry Sound for more than 30 years and to him, it’s a no-brain calculation. “As long as there is enough water for the dock to float and the boats to pull up alongside, then it’s fine.” In some knee-deep waters, however, a combined effort might be necessary, using a long ramp or a section of pipe dock to span the shallows before connecting to a floater at the end.

While floating docks can be designed and built to withstand brutal assaults of wind and water, some extreme locations — like a heavenly bit of Lake Superior shore that bears the full brunt of that big lake they call Gitche Gumee — might make them a poor choice. Such unceasing wave action would make walking on the dock almost impossible, guarantee damage to boats moored alongside, and eventually tear the dock loose from its anchors. Floaters not welcome.


How much dock do you really need?

Okay, so the water in front of your cottage is more than a metre deep and hasn’t yet been featured in a Gordon Lightfoot song. The next question you’ll need to ask is how much dock do you really need? You’ll need a spot to pull up a boat or two and, if you’re like most cottagers, some guest parking is required. How big are those boats? Do you have a PWC? Do you tie the canoe up to the dock or just haul it out on the beach? Watercraft may be the first items that come to mind when calculating dock size, but most of their bulk stays in the water. Sun worshippers, lounge chairs, and watertoys are what really determine the square footage of your dock. “If you’re going to use it strictly for boats, you might just want one long main -finger, perhaps with a few slips coming off it,” says Blower. “But if you want it for sunning and swimming, you’re going to need a larger dock, possibly a large rectangle or square.” It’s the simple geometry of floating docks — which can be built as discrete squares and rectangles and then put together in letter-shaped formations, T, L, or U — that gives them flexibility. And while the basic rectangular boat dock is still common, more and more cottagers are creating elaborate waterfront spaces with specific areas for moored boats, children at play, and adults at ease. “We look at docks as a fairly economical way to increase your waterfront,” says Tom Hopper of Polywest, a company in Winnipeg that designs and builds docks, sells dock kits, and manufactures Seaco Marine dock floats. “Especially in areas like Muskoka where land is getting pretty dear and many cottagers don’t have the luxury of a beach.”

Once you’ve considered how much dock you need, your first stop should be the local municipal office because, as likely as not, you’ll need a building permit for your new dock. A work permit is no longer required from the MNR for floating docks, but the municipality will check ministry maps to determine if your shoreline is designated as a sensitive fish habitat. If your cottage is on a federal waterway, such as the Trent-Severn, you will need to contact Parks Canada for written authorization (your municipality will tell you how). The only other bureaucratic wrinkles you might encounter would be if your cottage is within the jurisdiction of a Conservation Authority (you’ll need approval from it) or if the municipality determines your new dock might have an impact on public navigation, in which case, the Department of Fisheries and Oceans will need to be consulted before you build. Most times, though, permit approval is a one-stop shop at the town office.

Width and weight

Anyone who’s ever done the hippy hippy shake down a skinny finger dock at a marina can attest that most narrow floating docks are inherently unstable, their light weight and high centre of gravity — making for a top-heavy dock — practically guaranteeing a dip in the drink. “In order to have a good stable floating dock it should be long, it should be wide, and it should be heavy,” says Dan Doig of Dock in a Box, a company that specializes in modular dock systems.

A wide, heavy dock, with flotation located around the perimeter and a low centre of gravity, can better resist the effects of wave action and a load of people than a narrow lightweight model. As one end of the dock is forced up by the crest of a wave, the buoyancy of the other end resists sinking, and the weight of the dock slows its reaction time. Similarly, when two beerbellies step on one end of the dock, trying to sink it under, gravity holds the opposite end down, helping the portion under load stay afloat. “On a lighter-duty dock, the reaction time is fairly short,” explains Hopper. “If you stand on the edge, you’re going to go down, and if you move away you’re going to go up very rapidly.”

For this reason, many builders won’t construct a floater smaller than two metres by five metres, while for others, 2.5 by 6 metres is the minimum. The shape is also a factor: As you create T- or L-shapes, the extra mass and span of each section adds to the stability of the whole.

This article was originally published on June 14, 2005

Jump to a section

1 comment

Sort order:

Oldest Newest


Jan. 21, 2014

11:57 am

Great article, I can't wait to get out there in spring and make this a reality. Thanks for sharing your genius with us! Thiago |

You need to be logged in or a registered user to leave a comment

Log in  |  Register

Tonight on Cottage Life

  • No listings available
View Full Schedule


David Zimmer