Roll-In Docks

The roll-in was designed to permit quick installation and removal of dock systems on Minnesota’s and Wisconsin’s  vast glacial lakes. Many of the glacial lakes have gently sloping shorelines.  We have found 32 feet to be an extremely common length when all sizes are averaged out.  This length is ideal for a roll-in system.  The typical roll-in dock consists of two 16-foot sections with or without an “L” on the lake end.  The first 16-foot section comes with a set of support legs about 12 feet from the shore end of the dock.  The next 16-foot length will generally be set up with an axle and wheels situated about four feet from the lake end.  Optional wheels can be added at the starting shore section. This allows one to roll the complete system in and out without ever picking up the frame.   The wheels used in a roll-in system typically where  old tires from salvage yards, or “space-saver” spares.  Nowadays, most companies have gone to roto-molded plastic wheels.  Several advantages come with this development.  Since the material is rigid plastic, tires won’t go flat.  There are no metal components to rust.  These new tires address the buoyancy issue, since they are hollow and will fill with water when submerged.  The old style car tires on lightweight aluminum framed docks can add flotation to the system and therefore decrease some of the stability. Another advantage is aesthetics.  It was difficult to come up with matching tires in many cases.  The tires would be of the same height, but of a different tread pattern. This was not always acceptable to the customer.  Now, all tires are the same,  and therefore on long installations,  there is consistency in the looks from end to end. The final advantage is that they are completely recyclable when they have outlived their useful lives.  No bearings are used in the wheels on a roll-in system, since the distance they must travel is generally less than 100 feet.

Marine Dock and Lift carries two brands of roll in docks,  Private Island and Shoremaster.

Each carries it’s strong points

With Private Island the dock frame is made of  galvanized steel, or aluminum. Aluminum being the most common frame material. The frame is the “truss” style.  The dock sides consists of two parallel pieces of tubing reinforced with truss-style bracing for reinforcement.  This design can support heavy downward loads on the dock consistently.  Private Islands aluminum truss frame carries a double full length stringer on all sections.  This came into being with the usage of vinyl’s for decking. The vinyl’s do not have the structural load carrying capabilities that the wood and aluminum deck panels have.  Primary advantage to the truss style frame is it’s light weight.  The frame depth is approx. 11” deep. A ridgid frame can be built while keeping weight down.  This makes for a roll in that is relatively easy to install and remove from the water.

As mentioned in the sectional area,  Private Island offers many decking choices.  A grooved cedar decking in 4x4 panels.  An aluminum decking with vinyl insert.  An all gray panel style decking.  Injection Grate gray vinyl.  And finally,  Durodeck marine grade permanently attached plywood.

Shoremaster  is our other supplier of roll in docks.  They feature a frame we call a “solid” side design, or “large tube construction.”  This design is also made of  aluminum.  The solid side design is 6 ˝” in depth.  To get the strength and rigidity of the truss style,  the wall thickness of the frame is increased.   Therefore,  the dock is heavier than the truss style.  It typically carries  a higher price tag because of the extra material.  The Shoremaster solid side system is a quality built roll in.  It is very clean in appearance.  And it’s appearance is one of the reasons many customers choose to purchase it.  The decking lies flush inside of the frame system.  No edges of the decking are exposed.

The Shoremaster also includes large aluminum internally adjustable legs.  This allows height adjustment from on top of the dock.  All Shoremaster decking is removable in panel form.

Cedar, IPE hardwood, white painted aluminum panels,  and vinyl in 2002.

I should note,  treated wood is not an option offered for any docks we sell with removable panels.  Experience has shown us that the treated material will warp and twist in the sun.   If treated material is used, it needs to be firmly attached.  Even then, it may still try to twist or warp as it is exposed to the hot daylight sun.   The other disadvantage to treated is the weight.  The treated panels tend to be considerably heavier than cedar or the vinyl’s.

The main reason people buy roll-in docks is the ease of installation and removal.  Be cautious though, when pulling or installing a roll-in.  More roll-in docks are damaged by improper removal or installation than from storms or from boats tied up to them.  To remove the dock from the lake, one would take up the decking, pull up the support posts, then pull the framework out of the lake on its wheels by hand or with mechanical means, if necessary.  It can be as quick as a fifteen-minute process if conditions are ideal, without steep hills and with ample space on shore for storage.  Installation is reversed, except that additional time may be required to make the final adjustments to the support legs if the water level has changed.  Greater lengths can be created by using hinge kits between each 32-foot or 48-foot roll-in length.  Installations in the 128-foot range have been pulled out as a complete unit by a truck or small tractor.  Winch kits or adjustable screw legs are used to raise or lower the full length of the dock to a desired height above the water.

The disadvantage of a roll-in dock system become apparent when the dock is not sufficiently braced in deeper water (five to eight feet).  An unstable, side-to-side shimmy can result, which is unsettling to some dock users.  A cross chain kit added to form an “X” bracing under the lake end eliminates this type of motion.  Another option that creates stability is to add poles that auger into the lake bottom and attach to the dock with brackets. 

When removing, if  pressure ridges, bank cutouts, and or muck is present, caution is required.  One may need to lower the lake end into the water to stabilize the upright poles for removal.  Another tool could be ramps to go over the berm.  Ramps can be as simple as 2 pieces of longer wood.  The tires on the roll can ride up onto the ramps. This keeps the uprights from being bent or damaged should the wheels become stuck in mud or lodged against a berm when being pulled out. 

Roll-in docks are easy to install, remove, and adjust to changes in lake levels when used in an appropriate environment.  They are a  popular style of dock in Minnesota and Wisconsin.