Have you ever tried shouting across a small lake? Easy, isn’t
it?
How about when you’ve been waterskiing, and try to get
the attention of the tow boat? Found it impossible, didn’t
you???
Sound does and does not carry over water well. On calm lakes,
bays, creeks, or in restricted visibility, sound carries exceptionally
well. If you ever went camping around a lake, knowledgeable
campers often would tell you to keep the noise down at night,
since cool air, and a flat water surface amplified the sound
you were making, so that everyone on the lake heard you.
According to Howard Shaw, Ph. D. and Cheryl Jackson Hall, Ph.
D., “Experience suggests that sound, like light, travels
(more or less) in straight lines. However, to the contrary,
sound actually tends to curve downwards over a lake's surface.”
“Sound traveling along straight lines would disperse
quickly into the space above the lake. Instead, sound that "should"
rise up and be lost typically curves back down to the lake/ground
level. Therefore, it sounds louder than it "should."
This is a well-known and easily demonstrated observation, measurable
out there on real lakes.”
[https://www.mnresponsiblerec.org/resources/sound.htm]
But, let us go back to our waterskiing incident. The water
isn’t flat; it is a jumble of waves in all directions.
Why? Because the tow boat is throwing a wake, your water ski’s
are throwing its own wake, and with the tow boat serving and
changing course to give you - the rider - a great time, the
water has become choppy.
So our wave infested lake, stops your voice from traveling.
If this was a large body of water, the wind would be causing
the waves. In both instances, the sound of your voice would
have difficulty in being heard over the sound of the waves and
the interference that the waves would produce to your voice.
Add to your problems is the pitch of normal adult voice. It
would have problems piercing the noise, and because it’s
a lower wave length, it would also have difficulty moving around
the waves themselves.
So how can you be heard? By using a Low Tech Solution, an emergency
whistle!
An emergency whistle costs under $7.00, usually comes with
a lanyard, which can attach to your PFD. Every member of your
boat crew and guest should be familiar with their PFD, its emergency
whistle and mirror.
A whistle and a mirror, two low cost, low tech emergency solutions
that can just save your life.
So the next time you go to the boat store, why not pick up
a signal mirror and a whistle and attach it to your PFD. Low
Tech Safety Items – they might just save your life!
