Wednesday, May 11, 2011

NOAA's sea state of mind

Last night started beautifully clear, but by 3am there were squalls everywhere and we had rain and squalls until about 9am, then overcast most of the day. Tonight is very clear with a brilliant half moon that set beautifully into a cloud around midnight leaving a dark but star filled sky.

I've decided, or accepted the obvious, that sea state is the most critical component to onboard comfort and sailing performance. In NOAA's sea state and wave period charts the waves are nicely organized and labeled with heights, direction arrows and periods. The sea state depicted on those charts exists only in NOAA's computers or some desk bound meteorologist's mind. They do not exist in the open ocean.

We have had two weeks of the most confused and erratic seas on this passage that I've seen since we crossed the gulf stream in 2008. They do not appear on NOAA's weather faxes. The last two days are particularly odd as New Morning seems to rapidly accelerate and decelerate, like sailing through speed bumps made of peanut butter. She surges forward, then decelerates rapidly, then takes off again. The GPS will show our speed over ground (SOG), dropping from over 8 to 6, then back, in the space of two seconds. Then throw in a lurch or two as we hit a pile of water that bumps New Morning six inches to the left or right. If you're standing, it's usually the six inches that separates a hip from something solid. Add in a steep short wave from near the beam that will New Morning sharply one way then the other so that the mainsail backs with wind, then snaps back hard as we counter roll and the sail is slammed full of air, shuddering the entire boat. I have a preventer set to keep the boom from moving, and a running back stay set to further support the mast. These help reduce the jolts to the spars and hardware, but also help to distribute the shock throughout the boat. It's a feeling with which we never get comfortable.

Erratic movement aside, the wind has dropped a bit to 13-17 and the favorable current is gone. We're left trying to punch through the waves fast enough to reach Fatu Hiva by Thursday mid-day. At 13kts we're underpowered as the waves push us around and our speed drops to the 6's. With 17 kts we're sufficiently powered up to push the water aside and maintain the 7-8kts we need to reach our destination. While the wind speed cycles up and down, the direction also oscillates from roughly east to east-south-east which affects our ability to sail directly to our destination. The next 24hrs of wind speed and direction will determine whether we're sitting at anchor on Thursday night drinking champagne, or hove to 30 miles off shore and bob around waiting for Friday's sunrise.