The Marina Limited Partnership
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As boats are being pulled out of the water across the state and often headed to the local marina or boat dealer for winterization, many homeowners who don’t live on the water year-around often forget about the important maintenance necessary to maintain your dock and pier investment so that it’s ready to go next Spring.

Appropriate freeze protection can often be found in two main types of systems: the submersed thruster or agitator and the dock bubbler. While ice usually forms in shallow areas without circulation, in the northern part of Indiana, freezing can come on pretty quickly.

An agitator is a submersible motor with a propeller. It works under the water and is fastened to a dock using a rope or some are mounted to piers. The spinning propeller causes a flow of the warmer water to rise to the surface, thereby melting the surface ice. Agitators also create ripples on the surface, which prevent ice from forming. Agitators work best in deeper water. Some boathouses may have 2 or 3 agitators.

A bubbler, in contrast, is a system of perforated pipe or tubing on the bottom of the lake surrounding the dock structure, along with an air compressor or blower. Air is pumped through the tubing and the resulting bubbles keep ice from forming as they rise to the surface. Bubblers work best in shallow circumstances.

For the purposes of this article, we will just call them ice-away devices. The purpose of an ice-away is to create an open water buffer between the structure and expanding/contracting ice. In the absence of various regulations or none across lakes in Indiana, we’ve compiled a “Best Practices” list for the use of ice-away devices, but be sure to check with your homeowners association for lake specific recommendations or guidelines.

Best Practices:

Placement is Key
If an agitator is used, then angling it toward the shore directs the flow inwards, and not out into the lake, minimizing the amount of open water created.

Install a timer.
Operating your ice-away device 24/7 from fall to spring can result in excessive open water, not to mention an expensive bill. Eight to 12 hours per day is usually sufficient to maintain an appropriate amount of open water around your structure in most of Indiana, however a local marine contractor can advise you of your specific needs.

Using a timer and/or thermostatic switch also reduces energy consumption and saves you money. Even running your device at four-hour intervals over a 24-hour period will cost less than continuous operation. Unnecessary running time can also be controlled by setting a thermostat control that switches the device off if the air temperature is above freezing.

Mark Open Water with Warning Signs/Lights
Display signage to alert others to the potential danger of open water. These signs are available at most hardware stores or where ice-away devices are sold. However, signs will not prevent animals from falling in; some property owners also put yellow warning tape and fencing around the open water.

Monitor Your Property
If you are not using your property in the winter, have it checked periodically to ensure your ice away-device is working properly and that warning sign(s) and lighting is in place.

Be Ice Smart
No ice is without risk. Snowmobilers, skiers, skaters and hikers should exercise caution while on the ice and stay well clear of docks and boathouses.

For a list of marine contractors, please visit our resource list online at

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