Wednesday, October 23, 2013

What's the Frequency Kenneth?

Beaufort to Wrightsville is one of the few opportunities to leave the Intra-Coastal Waterway (ICW) and sail along the coast. Not only does this save time (a full day) and fuel but it is also the more enjoyable option because of the sailing vs. boring (but easy) canal motoring. Our passage planning was all set, our route plotted, it's a long trip so we'd have to get moving before sunrise. The only issue was the marine weather forecast:
Wind: North 10-15kts – Gusts 20kts
Waves: Height 2-4 ft + Period 5 secs

Oh how we wavered. Debated. Researched. Waited for an updated forecast. Mulled further. The one thing for sure was that we wanted to leave, keep moving. Before going to bed we decided, to our dismay, to take the ICW instead of the ocean route. The variable of contention was the wave period. This lesser known wave characteristic is very important; wave frequency, i.e. how often are we rocked & rolled. Combined with the wave height this can make a huge difference between a good day and awful day. We'd done 2-4ft waves before, but with a period period of 8 seconds, relatively comfortable. This forecast was for 5 seconds, almost twice as frequent. The rule of thumb is that if the wave period(secs) is close to the wave height(ft) it will be pretty rough and choppy. 4ft waves every 8 secs OK, but 4ft waves every 5 seconds, sounds like a washing machine.

We were very disappointed to see, too late, that the early morning forecast had changed to a wave period of only 9 secs! Totally doable. So today's lesson learned is: if the forecast is obviously really bad, don't go, but if it's borderline,...wait... prepare as if you were going... then call it off at the last minute. If we had woken up 5:00 we would have seen the updated 4:54 forecast and taken the opportunity. Instead we resigned ourselves to the ICW before bed and by the time we saw the latest forecast we missed the window of opportunity. Lazy, we were lazy. Not our proudest moment.

Anyway we're in Wrightsville now safe & sound. We hear good things. We'll see in the light of day.

Through Marine's Camp Lejeune

1000 nautical miles under our keel!
Anchorage in Beaufort NC
Wild horses were our neighbors... I couldn't stop singing U2
A wedding at the marina. I did not want to mess up this docking!
No help
Power Up
Yummy apple crisp smelled sooo good
Rough dinghy! I love the empty 40oz. bottles of malt liquor !
Oyster shells are land scapping option
See the effects of salt water? This bike was left here this morning.

1 comment:

  1. That's some good information to have, John, about the wave period. I knew about the period, but never heard it put in terms of the wave height versus period. The closer the numbers, the worse it is. Love it. Thanks!