Firstly the pump you are using is probably a piston air compressor and if it's one of the popular brands like a Brookwood or Sweetwater or Stratus air compressor they will run quite hot. The heat generated by the pump could be the result of over working due to some sort of blockage or backpressure but indeed these air compressors do get extremely hot and most models will burn your skin if you touch the cowling near the piston cup or air discharge.
Check all air filters. Ensure proper ventilation. Most commercial aeration systems using these pumps come with a ventilation fan. If you build your own dock bubbler system don't neglect ventilation. In most cases the high temperatures are not anything to worry about but it is best to ensure the heat is a normal mechanical creation or a problematic symtom of a faulty installation or mis-sized bubble tubes.
With the depth of water you have I would use a submersible style of agitation deicier. The motor is designed to be under water so won't be any issues of overheating. You suspend the system from the mooring ropes that attach to the protective cage. The unit is about 12 inches of the bottom and pushes a current towards the surface. The 1/2 HP unit would keep an area of 40' in diameter open.
By using a thermostat timer you can reduce power costs, although the unit is only 5.3 amps. The thermostat will turn on the deicer only when the temperature goes well below freezing and then the timer allows you to operate it for 4 or 6 hours on and 4 or 6 hours off. With the C20 thermostat unit there is a detailed schedule sheet that recommends the best operationalon/off times.
Try and place the deicer at the furthest point from the shoreline where the water is deepest. Angling the thrust of the motor towards the shore and adjusting the attck angle to slightly off horizontal allows an oblong or oval shaped opening to form. A 100% vertical thrust will leave a uniform circle of open water.
Using an angled placement is good for creating long landing zones for waterfowl when using a bubbler for duck hunting.
While bubblers can be good especially when the laws of your state restrict the use of deicers I prefer the submersed systems myself in most cases...less issues with clogging as you've seen. There is a definate need for the air diffuser bubbler system in the ice protection toolkit but setting a water cooled Ice Eater into a boathouse or along a slip between some pilings is much easier to install and maintain than a submersed system of sunken hoses.
There is a horizontal float unit for the submersed deicers. It allows you to float the deicer out further and aim the flow towards the boathouse. Even though it is suspended only 2 feet below the surface it still works well as a deicer. The other option would be to use the dock mount kit. The kit contains a bracket that holds the motor and allows you to attach a 10' long 1" steel pole to your dock so you can extend the deicer out further into the deeper water. The newer dock mount kits allow 1.5 inch heavy dity poles and are a good fit for commercial marinas and boat owners who have a large investment to protect. There is a horizontal float unit for the submersed deicers. It allows you to float the deicer out further and aim the flow towards the boathouse. Even though it is suspended only 2 feet below the surface it still works well as a deicer.
The bubblers can also use the thermostat controller but the problem is with bubblers that there is the potential for the airline to freeze and block if the compressor is off.
I would check if the compressor is running at a normal hot temperature or if it is indeed overheating and if the bubbler worked last winter it would likely keep working this winter as well. Most bubble tube type systems require some verification that build-up or organic slime has not impeded the holes where air should flow. Running tests and verifying the visual exit of homogoneous bubbles prior to freezxing temperatures is a good practice.
The Ice Eater® is an appropriate system for dock protection in most situations. The model P500 or P750 would be a good fit with your boat house. More info and specs here
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