cbigma
Well-known member
I’m not a social tooter.
That doesn’t mean I’m an anti-social tooter, it just means that I’m not one to announce my every transit of the harbor with a blast of my horn. I only use my horn when I need to get someone’s attention –immediately.
When stonebuster started the thread on “pilothouse trumpet horns” over on the All Parker Boats section, it got me thinking. Why don’t they make powerful air horns that are loud, long-lasting and reliable? And why do they all seem to stop at 120 decibels?
I did some digging on the Web and bought this single trumpet horn rated for 120 DB at 300hz at Hamilton Marine for about $120. About the same as what I paid for my last two sets of electric horns that only lasted a season.
It came with a cute little air compressor, but somehow even 120 db didn’t seem quite loud enough for me.
So I Googled around a bit and discovered that the more air pressure you put into these horns, the louder they get.
I did a little experimenting and found that I could actually blow into the trumpet and get it as loud as the little aquarium-pump compressor they give you. The harder I blew, the louder it got! When I realized how annoyed the Admiral became with this experiment, I kept at it until I nearly split my cheeks. I had the dog howling, and the cat running for cover. I stopped only when she had that Lorena Bobbit look in her eye. :shock:
The little air compressor that came with the horn was only rated for 10 psi , . If you get 120 db for 10 psi,,, what would happen at 20 psi. 30 psi? But I’m getting ahead of myself……. 8)
First I had to find a place to mount this single 17” trumpet in a way that would prevent it from gargling salt water whenever we left the harbor. I butchered the old SS brackets from the last set of electric twin trumpets that died, and rigged the horn with a downward angle, using the bolts for the Raydome mount. (I –did- check afterward, and the trumpet is clearly “under the radar” and contains no electrical components.)
I also replaced the clear flexible aquarium tubing that came with the horn because the OEM tubing walls were too soft and thick and I wanted to crank up the pressure. I wanted a more rigid tubing, so I didnt lose anything to tubing expansion I substituted polyethylene tubing with a thinner wall. It is not as flexible, but was thinner walled for the same OD, giving me greater volume and higher pressure capacity.
I ran the tubing down through the same cable outlet as the Radar feed. I then ran the tubing through the conduit above the stbd windshield, then down along the window frame and through the dash. Finally out the bottom by the helm onto the deck.
Now for the air power. What to use to crank the volume up a bit? A bigger compressor? A SCUBA tank? Something that could give short bursts of low volume air in excess of 50 psi, without too much weight or electrical components. Hmm………
A foot-operated bicycle pump should do it. This one, a Bell air-stomper foot pump is rated to 120 psi, and cost about $14 at your nearest sporting goods or bicycle store.
There was hardly any traffic out there today, surprising for a clear spring day, but the wind was brisk. I wanted to get a few miles offshore for the trial. I had no way of measuring the intensity of the sound, or any clue as to what I should expect. I foolishly stood up on the bow and challenged my son to “step on it”. Don’t try this at home.
Now I know why they all stop at around 120 decibels. I did experience pain and I still have a ringing in my ears. There is an air gauge on the pump and we were up somewhere around 40 -50 psi with a single stomp. I have no idea at what psi the diaphragm in this horn will rupture. I do know that replacements are available.
Be careful. Tampering with these horns could result in permanent hearing loss.
John
That doesn’t mean I’m an anti-social tooter, it just means that I’m not one to announce my every transit of the harbor with a blast of my horn. I only use my horn when I need to get someone’s attention –immediately.
When stonebuster started the thread on “pilothouse trumpet horns” over on the All Parker Boats section, it got me thinking. Why don’t they make powerful air horns that are loud, long-lasting and reliable? And why do they all seem to stop at 120 decibels?
I did some digging on the Web and bought this single trumpet horn rated for 120 DB at 300hz at Hamilton Marine for about $120. About the same as what I paid for my last two sets of electric horns that only lasted a season.
It came with a cute little air compressor, but somehow even 120 db didn’t seem quite loud enough for me.
So I Googled around a bit and discovered that the more air pressure you put into these horns, the louder they get.
I did a little experimenting and found that I could actually blow into the trumpet and get it as loud as the little aquarium-pump compressor they give you. The harder I blew, the louder it got! When I realized how annoyed the Admiral became with this experiment, I kept at it until I nearly split my cheeks. I had the dog howling, and the cat running for cover. I stopped only when she had that Lorena Bobbit look in her eye. :shock:
The little air compressor that came with the horn was only rated for 10 psi , . If you get 120 db for 10 psi,,, what would happen at 20 psi. 30 psi? But I’m getting ahead of myself……. 8)
First I had to find a place to mount this single 17” trumpet in a way that would prevent it from gargling salt water whenever we left the harbor. I butchered the old SS brackets from the last set of electric twin trumpets that died, and rigged the horn with a downward angle, using the bolts for the Raydome mount. (I –did- check afterward, and the trumpet is clearly “under the radar” and contains no electrical components.)
I also replaced the clear flexible aquarium tubing that came with the horn because the OEM tubing walls were too soft and thick and I wanted to crank up the pressure. I wanted a more rigid tubing, so I didnt lose anything to tubing expansion I substituted polyethylene tubing with a thinner wall. It is not as flexible, but was thinner walled for the same OD, giving me greater volume and higher pressure capacity.
I ran the tubing down through the same cable outlet as the Radar feed. I then ran the tubing through the conduit above the stbd windshield, then down along the window frame and through the dash. Finally out the bottom by the helm onto the deck.
Now for the air power. What to use to crank the volume up a bit? A bigger compressor? A SCUBA tank? Something that could give short bursts of low volume air in excess of 50 psi, without too much weight or electrical components. Hmm………
A foot-operated bicycle pump should do it. This one, a Bell air-stomper foot pump is rated to 120 psi, and cost about $14 at your nearest sporting goods or bicycle store.
There was hardly any traffic out there today, surprising for a clear spring day, but the wind was brisk. I wanted to get a few miles offshore for the trial. I had no way of measuring the intensity of the sound, or any clue as to what I should expect. I foolishly stood up on the bow and challenged my son to “step on it”. Don’t try this at home.
Now I know why they all stop at around 120 decibels. I did experience pain and I still have a ringing in my ears. There is an air gauge on the pump and we were up somewhere around 40 -50 psi with a single stomp. I have no idea at what psi the diaphragm in this horn will rupture. I do know that replacements are available.
Be careful. Tampering with these horns could result in permanent hearing loss.
John