Monday, September 29, 2008
The Ocean, She is Loud
Consistently, the loudest noise is the slapping of water against the hull. Even time spent cruising bays, sounds and inner passages and nights on a rocky anchor does not prepare you for the volume of wave slap in ocean swell. There are swooshy gliding sounds as the boat surfs over and through waves. There are splashy splochy sounds as waves crest nearby and drench the deck. Then there are the wappy, smacky sounds as wavelets beat themselves to death on the obdurate fiberglass of the hull.
The ones that really get you going, though, are the really loud bangs which sound exactly like a 2 x 4 wielding sea monster has reached up from the depths and rapped your boat sharply on her nose. These whacks do not in any way sound like water. You will be convinced the first two to three hundred times this happens that the boat has just run into a large tree. It is, even after the thousandth time, nearly impossible to comprehend that the sound is generated by a wave bashing its head against the beam. I challenge you to sleep through these even with the most highly evolved hind brain.
Catamarans in particular are also plagued by something known as "bridge deck boom." This is the sound generated by waves slapping against the bottom of the bridge deck between the two hulls. All catamarans boom. Or more precisely, for every catamaran there is a set of wind and wave conditions which make the boat boom. Designers around the world work to reduce the boom through baffles, angles and nacelles, height above water, and other factors. This results in models which are more "boomy" than others. However, no design escapes booming entirely.
When you get a boom condition, a large volume of water hits the underside of the salon like a toddler with a drum strick on mommy's favorite antique dresser. The shape of the boat, the air space within, create a perfect resonating chamber. The boom radiates out of the salon and down into the cabins where it works its way from your feet up to your eyebrows and fades out the top of your head.
In addition to wave noise, sound emits from your source of fuel. If you are motoring, there is the constant drone of a large diesel engine. If the wind is strong enough to enable you to sail, it is strong enough to vibrate the mast and tensioned running rigging. If the wind is really strong, the combined wind and wave outside sound like a freight train rolling over the boat.
At 0400 having been on watch for three hours, with the red lights dimly illuminating the salon, a new sound emerges. The sound is deep, low, liquid, and buzzes along the nerves with the after effects of sleep deprivation, over caffeination, and exhaustion. This is the sound of my brain melting.