Safety Whistle Field Test

At the Western PA Solo Canoe Rendezvous last weekend we did a field test of the sound range of a batch of safety whistles. Several of us took a half dozen of our own assorted whistles partway around the little pond we were camped beside for the event, leaving some folks at the launch area to react to out auditory tests.

As we lined up with whistles at the ready, Becky, who organized the test, would direct each of us in turn to blow – the distant listeners would raise their hands when and if they could hear it. As we moved farther away some of the whistles performed better than others. The winner by far was the Heimdall – roundly beat several Fox 40s, a Shoreline Marine, a Windstorm and some generic whistles that looked like the Heimdall but were unlabeled. Besides being loud, the Heimdall design allows you to sustain the trill for longer than the others at a consistent volume.

I was impressed enough to order a batch of 6 assorted colors of the Heimdalls on line (they were less than $5 each and came with both 20" and 40" color-matched lanyards and a dozen cord locks) and plan to replace the whistles in all 5 of my PFD’s with one of these.

We also practiced the one, two and three blast signaling at distance and participants were tested on what the signals mean. That’s something that any trip leader on the water needs to go over with participants. I think most of us on here know that but I have run into plenty of people “leading” paddling outings who never even mention that, let alone assure everybody at least knows what means “STOP!”.

By the way, the assorted set of Heimdall whistles is purty, too (I’m like a pack rat or raven, drawn to bright colors.)


I got some from LONG ISLAND RAILROAD not sure on brand but they buy AMERICAN. I’m sure they tested them too. Track workers use them lives depend on them. I’ll look tomorrow.

Guy on FB PADDLING GROUP makes them on a printer. Black 8 bucks each no clue how good they are. Not what I would buy.

Is that railroad one pea-less? Our state specifies that paddlers must carry a pea-less whistle (I presume those with the vibrating pea don’t work as well wet so some sports coach whistles don’t pass muster.) When I tried to locate info about it I did find this recent article – appears somebody is blowing some pretty significant whistles on alleged mob-related corruption in the Long Island Railroad workers union:

That Heimdall was deafening during our test. I was too close to the guy using his one of the times he blew it and my right ear rang for a few minutes after the sonic impact. Anything louder would be painful to the user.

Cool test. Did anyone use a Storm whistle? I’d be curious to see where that ranked. I’ll have to remember this as a group activity for a club outing. I discovered the slim profile Fox just didn’t have the same projection power some time ago trying to get the attention of a participant whom was getting out of range from the group. That’s when I realized the importance.

See you on the water,
Marshall Seddon
The River Connection, Inc.
9 W. Market St.
Hyde Park, NY. 12538
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I’m also curious how the Storm would compare (willowleaf mentioned Windstorm). Storm is advertised as the loudest. They’re a bit bulky.

“some generic whistles that looked like the Heimdall but were unlabeled.” … yeah, I have one of these that came free with some purchase or another. It’s just about useless. I’ll give it to a grandson.

Thanks for posting this, willowleaf. I have a pretty good whistle on my PFD, but am tempted to order a Heimdall as it’s probably better.

And, don’t laugh. I feel like that guy who advocated using a foam pool squirter as a pump a couple of years ago. Wow, he got bashed! But I’ve found that a plunger-type party horn is also really handy for signaling. In non-rigorous comparisons with a few whistles, people in my group said it was the loudest. A catch though is that of several I bought at a dollar store about half were real duds - they sounded like they were wheezing and made little sound. But some are really loud. (BTW, even for just a dollar, the Dollar Store takes returns - I’m cheap)


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Interesting test. I’m going to do likewise and order a bunch of the Heimdall. I want to have one on all of the life jackets and the dinghy anyway. The ones I have now are generic that either came with some other purchase or were giveaways.

It would be interesting to do such a test with a decibel meter. While the phone apps may or may not be accurately calibrated, I’d think they would at least provide relative differences between the whistles. Perceived loudness also depends on the frequency and wonder if there are any perceptible differences.

Marshall, I had both a Fox and a no-name whistle that looked exactly like the branded Heimdall. With both whistles I found that no matter how I blew it (either all my lung power in a quick blast or trying to control and extend the blow) they seemed to have a built in cut off (kind of like maximum hull speed with a kayak!) and would stop producing sound rather abruptly even before I had stopped blowing. But with the Heimdall I have no trouble maintaining sound as long as I have breath to push through, I can also modulate the blast like a siren. (BTW, both my cats hate the sound and are very pissed at me for practicing indoors – may reserve one of the six whistles for household pet discipline).

There was one person in our field test with what looked like a Storm but I know there are knockoffs of that shape and he didn’t recall the brand from when he acquired it. It was one of the louder that we tested, but still not as shrill or sustained as the Heimdall. The Heimdall also has a molded-in clip that can attach handily to the wide webbing that is usually part of a PFD shoulder strap. I like the low profile design, too (based on my use of a Heimdall knockoff for a couple of years) and doesn’t pop out of the pocket as a couple of my chubbier whistles sometimes do.

I went searching for bulk wholesale on the Heimdall (to recommend it to my local outfitter friends) but they seem to only sell it in small quantities through Amazon. If one has Amazon Prime free shipping a 6-pack is $17.99 plus tax (which is $3.21 each in my PA county but would be $3 each with a resale tax exemption). Walmart sells them for $5.29 each, other vendors seem to price at $6.99 per unit so there is margin there.

One drawback to the 6 pack for a vendor is that the half dozen comes in pieces with two sets of lanyards and cord locks per whistle. So to sell retail you would need to either thread and lock the lanyards (takes about 15 seconds each) or package each whistle with its 4 accessory bits for the buyer to DIY whichever length cord they wanted.

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Heimdall states the whistle produces 120 dB (which is less than the 140 some of the other whistles claim). I was wondering during our tests if the fact that the Heimdall had a more pronounced tremolo contributed to the distance projection. I know wavering tones (tremolo/vibrato/trilling) enable vocalists to sustain a note more easily than constant tones – I wonder if we have any sound engineers on here who can tell us whether wavering sound is more readily detected by the human ear than an equal dB “pure” tone?

The Heimdalls are advertised as “pealess”. How do you get a tremolo or trill from a pealess whistle?

These might be of interest. This thread certainly got me thinking.

(29) Ultimate Survival Whistle Test 2020 39 separate devices tested and scientifically documented - YouTube

Supporting Document - Whistle Test | WATTRE INC

I wondered that too, but inspecting the Heimdalls, there are two parallel squared inlets you blow into that are different sizes. So the quavering tone may actually be a wave harmonic produced by two tones rather than an actual modulation of a single tone wave.


That video is really interesting (it’s pouring rain here so it gave me something to watch/listen to since I’m stuck indoors and the radio station went out.) But I notice some of the ones that the meter ranked as loud were either such high frequencies that they sound like insect or bird calls or so low (like the Giant Yellow Party Whistle) that they sound like an owl. To get people’s attention outdoors with a lot of background sound you need something that sounds distinctly man-made.

Both very :loudspeaker: :loud_sound: loud

One STORM other one just has a number on it.

Boats come close it’s in my :lips:. Sometimes to no avail. Pistol would be a better choice I think.

Yes, it is tricky. I carry a Fox 40, plus this: Air Horn for Boating Safety Canned Boat Accessories | Marine Grade Airhorn Can and Blow Horn - 1.4oz: Automotive

Small enough it fits into my “glove box” hatch in front of the cockpit. One time I got it out and was ready to use it, but the boater finally looked up and veered away.

Decades ago I bought a two-pack of Fox 40 Flats. Actually got to use one once or maybe twice; they work okay. At the time, they claimed it was the loudest whistle made; maybe it was. Still pretty good. One of mine is on the keyring with my car and house keys, but that is in my waterproof waistpack when I’m paddling, so I’ve put the other on a neck chain with a tiny compass.

I would NOT buy an emergency whistle that runs on batteries.

Some of the advertising hype is ridiculous. The Storm whistle ad says it even works underwater. Fine, but if I’m underwater I won’t be using my last lungful of air to blow a whistle that only the fish will hear.

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I have a Fox 40 on my PFD. It works for me.

Going back to the original testing did each person blow each whistle to take the human to human variable out of the test?

That would have been rather unsanitary, but we had several duplicate models being blown by assorted participants since everybody involved gathered their own whistles as well as some that were on the loaner PFD’s that had been provided by attendees.

I do remember that the guy who had the Heimdall (and was the only one to blow it for the test) also had a Fox 40 (as did I) and his results with that at the farthest distance we tested was not as good as with the Heimdall.

This was far from a precise scientific test – just a kind of fun exercise. Had I thought of it I would have grabbed one of my packs of hand sanitizer wipes and we could have passed the whistles around to allow for the individual lung power aspect.

Since getting my pack of 6 Heimdalls I’ve checked the model against my Fox 40 and the 3 other models I had been using (Shoreline, generic Heimdall clone and unlabeled Storm clone.) I like the sound and ease of producing an extended blast with the new one better than the old ones. The Fox was a very close second. YMMV.

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I figured as much, and my old six sigma training skills from before I retired kicked in and I had to ask.

I still need to buy her a whistle so maybe order up a Heimdall and give her my Fox 40.

Years and years of being around industrial equipment and also agricultural equipment left me with a loss of high frequency hearing men are easier to hear than women quite often. I can hear the Fox 40 alright but from the reaction of others I don’t think I’m getting the full impact. If someone is in trouble around me a fog horn might be what is needed to get my attention. :canoe: