Air Horn Installation

[Hick]

I plan on installing an air horn on our 1998 370 Express AJ. I plan on installing the air tank and compressor motor in the engine compartment. There is a step down there which also functions as a bench when one is down there checking the oil and other light duty chores. I plan to install the air tank to the underneath side of that step/bench. The tank is 22" x 7". From there I need to get power to the compressor motor and to a button at the helm. I also need to run an air hose to the horn, which will be mounted on the arch. Anyone with experience on this type of project? Any traps for the unwary?

 

[lawndoctor]

I installed a Kahlenberg on my old boat. I did not mount the compressor in the engine compartment because it was not ignition protected. You will want the air hose from the tank to the horn to be as short as possible. The compressor switch will need about a 20 amp circuit, the solenoid valve only a few amps, so you will need to set up the circuits and switches for those loads. I always hated the noise from the compressor turning on randomly, along with the need for an additional switch for the compressor, so eventually I put in an AFI air horn with the direct pump, no tank. The sound is just as good, and the installation was much simpler, just needed to add a relay for the horn switch. The forum has some detailed threads about installing air horns.

 

[Hick]

Please explain ignition protection, it sounds serious, like, random spark in the engine compartment protection?. Thanks for your input.

 

[Creekwood]

Please explain ignition protection, it sounds serious, like, random spark in the engine compartment protection?. Thanks for your input.

Its pretty simple. With gas engines, nothing should ever be installed in the bilge that is not marine rated and ignition protected. That means the items are designed to not expose sparks to the air in the bilge. A gasoline motor and tanks and lines in the enclosed bilge can allow gasoline fumes to accumulate. A small leak, or fumes coming out of the engine can easily reach explosive levels and any spark can cause your boat to explode. So don't do it.

 

[Westie]

Ignition protection is not just limited to "not producing sparks"
It also includes any hazard that could cause a air fuel mixture to ignite. This could be a electrical component that could get too hot.