Air Horn selection....

[Diesel Duck]

In another thread (now closed) Mark Pierce made the following statement regarding the selection of an air horn for his 35' Coot: "The chart shows minimal tone/range for various vessel lengths. I went one step above the minimum (deeper tone and half-mile range rather than quarter-mile)......." Note: I'm assuming the "chart" he's referring to is the chart shown on Kahlenberg's web site.

Link to previous thread now closed: http://www.trawlerforum.com/forums/s9/kahlenberg-k-380-air-horn-package-essentially-new-18464.html

The reason I'm bringing up this closed thread along with Mark's comment and his ultimate selection of a specific model/style of air horn (a Kahkenberg D2) is because while I was doing some research I came across information that, to my understanding, Mark's choice of air horns was not within the limits of the USCG's regs as described in their Navigation Rules Annex lll.

The rules, as I interpret them, state that a vessel of less than 75m is to have a horn/whistle that produces a frequency between 250-525 Hz. That being said, one of Mark's horns that make up the Kahlenberg D2 (the Kahlenberg D2 has two horns) produces a frequency of 212 Hz.

So my questions are.... Is my interpretation of the regs correct? Can you have too low of a frequency for your horn?

For reference, below is a copy and paste from Annex lll of the USCG Navigation Rules (for International Waters):

"§ 86.03 Limits of fundamental frequencies
To ensure a wide variety of whistle characteristics, the fundamental frequency of a whistle shall be between the following limits:
(a) 70-200 Hz, for a vessel 200 meters or more in length;
(b) 130-350 Hz, for a vessel 75 meters but less than 200 meters in length;
(c) 250-525 Hz, for a vessel less than 75 meters in length."

Link to the USCG Navigation Rules: http://www.navcen.uscg.gov/pdf/navrules/navrules.pdf

Link to the D2 on Kahlenberg's site: Model D-2 Chimetone Air Horn | Kahlenberg

Edited... Added content.

 

[markpierce]

Actually have D-1 horns (no longer listed in the Kahlenberg catalog).

The horns are 252 and 322 Hz with 134 dB. The manufacturer specified it for boats of less than 75 meters with no minimum length specified.

 

[Diesel Duck]

Actually have D-1 horns (no longer listed in the Kahlenberg catalog).

The horns are 252 and 322 Hz with 134 dB. The manufacturer specified it for boats of less than 75 meters with no minimum length specified.

Hmmmm interesting..... In your comment in the previously closed thread you said you had the "Kahlenberg D2 horns". Here's a copy and paste from that thread:

"Love my Kahlenberg D2 horns.......... four times the power of the 380 and twice the range. I over-indulged but do not regret. Just don't be on the deck forward of the horn. (An electric horn is standard on the Coot. I ordered the Kahlenbergs to be shipped to and installed by the builder. There was no extra charge by the builder for installation.)"

Regardless, I still would like to know the answers to my questions about there being a too low of a frequency for given boat length.

 

[markpierce]

Yes, I was mistaken, relying on an updated catalog omitting the D-1.

I believe you're correct on the limitations of frequency, but I think the volume specs are minimums. (Don't be on the forward deck when I blow the horns.)

 

[Forkliftt]

Interesting- I wouldn't have guessed there was that much science to air horns and I would have guessed wrong! Mark- what compressor is used to sound your horns?


Forky
1983 Present 42 Sundeck
Twin Lehman 135's

 

[markpierce]

Mark- what compressor is used to sound your horns?

This one from Kahlenberg. I don't have the specifics, but it has higher capacity than what would be needed with lesser horns. It too is no longer in the Kahlenberg catalog, but was the one recommended. A sizeable air tank is also used (and again not now listed in the catalog.)

 

[Diesel Duck]

Mark's compressor motor is a JUN-AIR OF322.

Performance Summary
Model OF322
System Type Motor
Market Beverage / Lab / Gas Generation
Displacement (50 Hz) 2.37 cfm (67 l/min)
Displacement (60 Hz) 2.97 cfm (84 l/min)
FAD @ Max Pressure (50 Hz) 1.41 cfm (40 l/min)
FAD @ Max Pressure (60 Hz) 1.55 cfm (44 l/min)
Max Pressure 175 psig (12 bar)
Noise Level (50 Hz) 72 dB(A)
Noise Level (60 Hz) 72 dB(A)

Here's the link: OF322 motor - JUN-AIR

 

[Al]

So I take away from this conversation that the purchase of a compressed air horn from the marine store for under $20.00 suffices the USCG regs and makes enough noise?

I purchased years ago, a wooden train whistle from the train promoton company that did or may still, run dinning train to Woodenville, St. Michele Winerey. Often though that a person could attach one of these air cans to it and have a hoot on the water with a train sound.

Al-Ketchikan

 

[Wayfarer]

http://youtu.be/lxULZTCyeEE

I'd quite like one of these. If I remember right, they're 50hz.

Also, On an unrelated note, how do I get youtube links to show up as a video on this page, instead of just a link?

 

[twistedtree]

I'm the guy who sold the K-380 horns referenced in the first post. They were significantly under rated for my boat (45' rated on a 65' boat). I ended up upgrading to the D-0A horns and compressor package which is IMO certified for up to 65', and I'm 64.5'.

The D2 was tempting, but I passed on them for two reasons.

First is the air requirement. They use a lot more air than the D-0A and consequently the specified compressor is significantly larger and 110V rather than 12 or 24VDC. Installation would have involved running a much larger air line through the boat and up the stack. By going with the D-0A I was able to use a 24VDC compressor mounted under the flybridge settee right where the old one was located, and utilize a much shorter air line run.

The second reason was cost. The D2 was significantly more expensive. I don't recall exactly, but $1000 for the D-0A vs around $4000 for the D2 sticks in my mind. The larger compressor drives up the cost, but the sounders themselves are a lot more too.

 

[dhays]

Holy Cr*P! 4 boat bucks for a horn? I need to get my wife to get a second job.

btw, Tanglewood is a lovely boat.

Dave

 

[Diesel Duck]

I'm the guy who sold the K-380 horns referenced in the first post. They were significantly under rated for my boat (45' rated on a 65' boat). I ended up upgrading to the D-0A horns and compressor package which is IMO certified for up to 65', and I'm 64.5'.

The D2 was tempting, but I passed on them for two reasons.

First is the air requirement. They use a lot more air than the D-0A and consequently the specified compressor is significantly larger and 110V rather than 12 or 24VDC. Installation would have involved running a much larger air line through the boat and up the stack. By going with the D-0A I was able to use a 24VDC compressor mounted under the flybridge settee right where the old one was located, and utilize a much shorter air line run.

The second reason was cost. The D2 was significantly more expensive. I don't recall exactly, but $1000 for the D-0A vs around $4000 for the D2 sticks in my mind. The larger compressor drives up the cost, but the sounders themselves are a lot more too.

Contributing to the thread drift....

It appears (by the numbers) that the D-0A is the replacement for the D-1 that Mark say's he installed on his Coot. The D-0A frequency of its two horns are listed as 322 & 254 Hz at 133 dB and Mark reports that his D-1 has frequency's of 322 & 252 Hz at 134 dB. The big difference between the two is that Mark's D-1 requires a 120V A.C. compressor whereas the D-0A can either be powered by 12 or 24 Volt D.C. compressor. Personally, I'd much prefer the D-0A for its ability to use 12 or 24V D.C. rather than 120V A.C.

I still would like to know if my conclusion regarding the USCG regs is correct???

 

[dhays]

I still would like to know if my conclusion regarding the USCG regs is correct???

Asking a bunch of folks on the internet if something is correct? Sure why not.

You asked earlier;
"Can you have too low of a frequency for your horn?"

I will give you an answer based on how I read the COLREGS. The easy answer is no. However, the correct answer is "it depends".

International USCG rules require that any vessel under 75m must have a horn with a fundamental frequency between 250-700 Hz. So if you have a sound device with one whistle, it needs to have its primary, or fundamental frequency, in that range. If it is lower than that range, then it doesn't meet the requirements.

Furthermore, there are specific sound pressure requirements to the whistle. This is where it gets interesting as it is possible for the fundamental frequency to not meet the intensity requirements but a higher frequency, either a harmonic or another whistle, could meet the intensity requirement.

Also, if you have multiple whistles that make of your "horn", 2/3 of them must have a fundamental frequency that fall within that 250-700 Hz range. So if you have three whistles (each much be at least 10 Hz apart in tone) 1 of them could be below 250 Hz or above 700 Hz if the other two are between 250-700 Hz. However, there needs to be enough sound intensity to meet the requirements. If you have two whistles, the one with the higher fundamental frequency has to fall withing that range.

Strangely enough, it appears that if you have a combined horn with 3 whistles, 2 of them could fall in the 250-700 range but not be loud enough to meet the requirements. If the third is loud enough, it can meet the requirements even if it falls outside that range, either higher or lower.

So, you can have a horn with a whistle that is lower than the 250 Hz provided that it also has a whistle, or whistles that fall within the 250-700 Hz range.

Inland rules are a bit different, the range there is 250-525 Hz. I am never in Inland waters so it wouldn't affect me.

You asked about that D-2 horn. It would meet the International requirements for frequency. It has 2 whistles separated by 54 hz. The higher frequency, 266 Hz falls within that 250-700 range. The specs of the horn don't give the sound pressure of the horn, but I would assume it is loud enough. That is something that you could check with Kahlenberg.

So, there is an answer. It is worth what you paid for it however.

Dave

BTW: if you read through all that congratz. Or you could simply check out Annex III, 86.13(a)(4) where it specifically addresses your original question as I understand it.

 

[Diesel Duck]

Asking a bunch of folks on the internet if something is correct? Sure why not.
.............................

Dave

Other than your smart alec opening shot I appreciate you taking the time to respond to my inquiry. Your answer makes sense.

BTW: It was my hope that out of all the TF members there might be someone who actually knew the answer to my question, possibly someone who either was with the USCG or someone who had investigated this with the USCG previously. Again, thank you for taking the time to respond.

 

[N4712]

Have you guys looked at Horn Blasters? I just got a set of train horns for my truck, I've tested them and they sound awesome. They make a marine line of horns worth checking out. They sell air kits and all.

 

[dhays]

Other than your smart alec opening shot I appreciate you taking the time to respond to my inquiry. Your answer makes sense.

Yeah sorry. I didn't mean for it to be taken that way. I just wanted to make it clear that mine is only just an opinion and a very non-expert one at that.

BTW: It was my hope that out of all the TF members there might be someone out there who actually knew the answer to my question, possibly someone who either was with the USCG or someone who had investigated this with the USCG previously. Again, thank you for taking the time to respond.

I was kind of waiting and watching for some knowledgeable input as well. Since no one did, I decided to re-read the regs again myself. For me, the COLREGS are always interesting and usually confusing

 

[siestakey]

Because of the earlier thread and research I bought this and is now on my boat

http://www.defender.com/product3.jsp?path=-1|135|2290125|2290127&id=179888


http://www.defender.com/product3.jsp?path=-1|135|2290125|2290127&id=1689993

and

http://www.defender.com/product3.jsp?path=-1|135|2290125|2290127&id=179917

the compressor I installed in my brow

 

[GFC]

In all seriousness, do you guys REALLY think the USCG is going to be out there measuring the frequency of your horn?


IMHO I equate horns to testosterone levels with a direct inverse relationship. The smaller the "tool" and the lower the testosterone level, the bigger and louder the horn is going to be.


Sort of like the old saying: "Got a small dick, buy a Corvette."


I have no idea the frequency of my horns. They're loud. At least the last time I blew them, which was a couple of years ago, they were loud. That just suits me fine.


Would I spend a boat buck to replace them if they died? Hell no. I'd rather spend that boat buck on diesel.

 

[markpierce]

My D-1 Kahlenberg set-up cost about four BOAT$. However, dropping the teak-deck option more than covered that, and represented only about 1.5% of the boat's cost, about the same as the import duty. The air compressor was offered in 120, 24, and 12 volt versions. I chose 120.

In my opinion, the minimal sound level for our-sized boats is only sufficient for signaling within a marina. Wanted something quite louder to be more effective. Didn't want a "22-rimfire rifle for hunting bears."

 

[Ski in NC]

A tractor trailer air horn and 110v pancake compressor works for me. Total price about 0.25 boat bucks. Compressor handy for other things, too.

 

[FlyWright]

I'm the guy who sold the K-380 horns referenced in the first post. They were significantly under rated for my boat (45' rated on a 65' boat). I ended up upgrading to the D-0A horns and compressor package which is IMO certified for up to 65', and I'm 64.5'.

I'm the guy who bought the K-380 horns from Twistedtree. (Thanks again, Peter!!) They're proudly installed on my 34 footer. When I first tested them after installation in my slip, the USCG crews who are docked behind my slip gave me an approval cheer.

They are appropriately sized for my vessel and are very loud! I have a fwd stbd door and felt they'd be too loud to use when the door is open so I mounted them on the port side. I try to always warn crew and passengers before sounding the horns.

The final cost due to an insurance claim on damage to the horns in shipping resulted in a final cost of 0.164 BU. Best $$ I've spent all year on my boat!

Model K-380 Chrome | Kahlenberg

 

[twistedtree]

The final cost due to an insurance claim on damage to the horns in shipping resulted in a final cost of 0.164 BU. Best $$ I've spent all year on my boat!

I'll try to smash more shipments, however UPS seems to be doing an excellent job on my behalf

 

[MurrayM]

Think we'll be going for this little electric one...123 dB @ 290 Hz;

International Shorty Horn | Marinco

Under $100.00 and has just the rugged swashbuckling machismo sound our vessel deserves

 

[FlyWright]

Think we'll be going for this little electric one...123 dB @ 290 Hz;

International Shorty Horn | Marinco

Under $100.00 and has just the rugged swashbuckling machismo sound our vessel deserves

Are you mounting that on your kayak? It might scare the birds out of your way.

 

[MurrayM]

Are you mounting that on your kayak? It might scare the birds out of your way.

Nope. The kayaks are for super ninja stealth mode approaches to wildlife, so no need for a horn. Then again, it could scare away the bigger critters if they ever figure out that kayaks are crunchy on the outside and chewy/juicy in the middle...

Actually, with the amount of vessel traffic where we live (usually have miles between vessels and anchorages to ourselves) the horn will be mostly for CG compliance. Planning on going to Vancouver in a couple years, so might need it then.

 

[Forkliftt]

Then again, it could scare away the bigger critters if they ever figure out that kayaks are crunchy on the outside and chewy/juicy in the middle...

Classic!!


Forky
1983 Present 42 Sundeck
Twin Lehman 135's

 

[O C Diver]

So I'm reading this thread and thinking it might be a good idea to upgrade to a Kalenberg air horn during the refit. How about a nice whistle also while I'm at it. It's probably an omen when they don't list the air cfm requirment for the whistles. Seems the one I like requires 1-1/4" pipe. Maybe I'll just focus on a horn.

Edit: Found it in the specifications, 838 scfm.

Ted

 

[GFC]

OK, nobody responded to my earlier thread questioning everyone's concern about the frequency of their horn, so I have another question:


How many times a year to you sound off with your horn?

 

[markpierce]

Sound my horn at least once each time I take the boat out. If no pressing need, to at least test its functioning. Same with the thruster.

 

[N4712]

Usually when crossing the Gulf Stream I'll use it couple times to verify it works. Other then that don't use it much.