It's a sad but true fact that water gets really hard in the northern United States. While most boaters who live in those parts will pull their vessels and store them on the hard before that happens, some folks choose a different path: They keep their boats in the water year–round. Some are liveaboards, while others feel their boats, often wooden, are best stored in their natural element, free from the stresses of hauling and blocking.

Dock owners and marinas also have a need to keep their equipment ice–free during the winter; specifically, they need to keep them safe from a phenomenon called ice jacking, which can destroy docks in tidal areas. During that unfortunate process, ice freezes around pilings at low tide. As the tide rises, so does the ice. This applies a large amount of force to the piling, sometimes enough to actually pull it out of the bottom. Each subsequent tidal rise and fall or change in river or lake level continues the process until the dock is destroyed.

PAUL ESTERLE

BUBBLERS AND CIRCULATORS

Whatever the threat, keeping ice at bay is a priority. There are two main systems for accomplishing this task: bubblers and circulators. But before discussing the various types of deicers, you might like to know why the warmer water is deeper than cold. As water gets colder, it expands and gets lighter. At around 39 degrees, the warmer, denser water sinks, while the cold, lighter water rises, where it starts to freeze when it gets cold enough. That boundary between the cold and warm water is called a thermocline. Deicers break up that separation and force warmer water to the surface.

A bubbler system consists of an air pump on shore that supplies low-pressure/high-volume air to an air line. That air line has either holes or slits that distribute the airflow along the length of the hose, creating bubbles as the air escapes from the hose. The bubbles mix with the warmer water and carry it to the surface. The warmer water coupled with the slight agitation of the bubbles keeps an area free of ice.

PAUL ESTERLE

Bubblers are typically used in water depths no greater than 15 feet. Below that, the air pressure required climbs, and the effect of the bubbles diminishes. The advantage of a bubble system over other types of deicers is that they are not prone to clogging from debris. It can also become uncovered at low tide without having problems – as long as the air remains flowing. The bubbler system will have to run continuously to prevent water from backing up into the air hose and freezing, possibly damaging the hose.

A bubbler system can be exactly tailored to a given layout. For example, lengths of unperforated hose can connect rings of perforated hose placed around pilings. The bubbles rising along the sides of the pilings will keep them ice-free without having to deice large areas. The air pump does need to be matched to the length of hose used to ensure enough bubbles are generated to do the job. You will need to work closely with the supplier of the bubbler system to create a system that is properly sized.

THE POWER HOUSE, INCThe Power House, Inc. "Ice Eater."

The bubbler must be turned on before the water freezes, as a bubbler system will not melt existing ice cover.

PROPELLER–STYLE DEICERS

These units are often called ice eaters, but that name is, in fact, a trademark of The Power House, Inc., which is one of two major players in the market, along with Kasco Marine, Inc. Kasco calls its units water circulators because they are also used to keep pond water mixed and stable. West Marine and other retailers simply call them deicers.

The depth of the water is an important factor in using a propeller-style deicer. The units must have enough clearance underneath to keep them off the bottom (suction!) and free of any bottom debris that might clog the propeller. In fact, propeller-style deicers should be checked regularly for clogs.

Kasco sells a float kit for its deicers. The kit supports the deicer in shallow water while allowing it to be mounted horizontally. This does manage to keep the water agitated and the ice at bay, but is not nearly as effective as a unit mounted in deeper water.