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Anke and I are building our next boat, and writing about it at ABargeInTheMaking.blogspot.com. Access to the net comes and goes, so I'll be writing in fits and spurts.

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Fair winds!

Dave and Anke
triloboats swirl gmail daughter com

Tuesday, December 27, 2011

Listen Up!

Oim Popeye, the Sailor Man!

This Able Bodied Seaman is what's known as a 'sensory homunculus'. He's modeled in proportion to the amount of brain given over to process sensory data from the various regions and organs of the body.  He has a brother - the motor homunculus - who is proportioned a bit differently, but still bears the family stamp. Bear with me... I'll eventually find some relevance.

What's coming is a trick I got from 'Nam. Not directly, being a couple of years too young and flat-footed at that, but through one of the many moving accounts of that war. In it lot of people spent a lot of time and energy moving around quietly. Lives depended on hearing the other guy before he heard you.

When fog, white-out snow and squall, or, to a lesser extent, darkness come down on a boat, we find ourselves in a sensorily analogous situation. Our best, distance delivery sense organs - the eyes - are shut down.

Next up are ears. They're our best shot, when running blind, at detecting another vessel, the breakers along shore, or rocks, or the hoot of a buoy. Radar doesn't tell you everything, doesn't always work, isn't always available. But I hope you're never separated from your ears.

So here's the trick, with commentary based on dim recollection:
  • Face the direction you wish to hear - Due to skull interference, we hear best from straight forward. Turn to scan the whole range of interest.
  • Cup your ears with relaxed hands - This multiplies the sound collection surface before feeding it into your ears. Don't bend your ears out of shape, as they're highly evolved to work as they are. Look at the mitts on our homunculus... hands take up a huge amount of brain power... relax them.
  • Close your eyes - They may not be able to make anything out, but, when open, the visual cortex , is working overtime, straining for detail. Closing them releases brain power to the ears (check out eye size on the homunculus).

  • Clear your eustachian tubes (pop your ears) - This equalizes pressure on your ear-drum, freeing it to vibrate freely and therefore increasing sensitivity. Also it provides an open, resonant cavity between ear and mouth, helping amplify vibrations (like a large guitar body, vs. a small ukelele). Learn to hold them open (a slight and particular tension in the jaws will do it, but you have to identify the muscle - like the onset of a yawn).

  • Open your mouth wide with tongue flat on the floor - The mouth, aided by teeth, makes a large acoustic chamber - almost a third ear - connected to the ear by the open eustachian tubes.

  • Be still - Still your mind and body. Don't strain to hear. Collect sensory data without spinning your wheels (but do wake up if urgent action is required!). Again, free up brain resources.

There ya go. Try experimenting, leaving one or more steps out, to get a feel for how much they add to your perceptivity. Some (especially holding eustachian tubes open and being still) take practice. So practice.

You'll be amazed at what you can hear this way, by sea or land. Try it when listening to music, or when out-of-doors. It adds a lot to bird-watching.

As a last thought, protect your ears! They are expensive, valuable equipment and irreplaceable... think of their value in terms of supply and demand.

The old fishermen joke, "Well... the motor's loud, but it gets a little quieter every year!"


4 comments:

  1. Great info....relevant to many more situations then straining to hear a coral reef on a moonless night. Tried it just sitting here: computer fan immensely louder. Didn't get a lot from the third cavity but if it was a coral reef situation think I'd try the whole list at once. May alert me to the sound of the wifes stealthy frying pan coming up behind me too.

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  2. I don't remember where I read it, but the sound waterfalls made along Chatham Straight were used as navigation aides. I often listen to them and can tell a difference between each one. I was amazed to hear them over 5 miles away. Must try these new listening techniques on them.

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  3. Water is a great locator along the Inside Passage. We use the sound of waterfalls and creeks often. They can provide an LOP, and (in some conditions) a distance off.

    In heavy fog, we like to anchor off the mouth of a creek. We can always find the boat, returning from a row, by listening for the water.

    That and pinpointing a steep creek for water... very hard to spot with the eyes.

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  4. One more ear thing:

    On a quiet night, if creeping tight along a rocky shore (feeling our way into a notch), you can hear the lip of water where sea meets obstacle.

    At low tides, you can hear the rocks themselves!

    Well... the barnacles covering them, anyway. They make a faint but distict, crispy sound. Check it out at the next dock piling. They even react to your approach!

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