The Alba Chronicles
Neville Howarth
Mon 4 Aug 2014 17:30



08:57S  158:03W


We're now just outside the entrance to Penrhyn, bobbing about waiting for the sun to get higher and for a gap in the rain showers, so that we'll have good light to see the coral heads once we're inside.  Here’s what we did yesterday and last night.


3 August 2014  Bora Bora to Penrhyn, Cook Islands (Day 5)

At 0800, we had 80 miles to go.  The wind was 10 knots from the north east as forecast, and we were bumbling along at 3-5 knots in 4 foot seas, planning to sail slowly for 24 hours to arrive at the pass into Penrhyn in the morning. Unfortunately, we were surrounded by heavy rain showers, some of which brought 20 knot winds and heavy rain.


It could have been a lot worse.  We heard reports on the net about the weather that others were getting.  Boats in Suwarrow spent last night on anchor watch with 25-30 knot winds as squalls went through - one boat apparently dragged and hit a reef.  "Scotia" (on their way to Samoa) had to heave-to in 54 knot winds and "Malua" was hit by a huge wave which ripped off his bimini and cause other damage - they both still have sustained winds over 30 knots.  Not exactly a "milk run".


The afternoon was pleasant being mostly sunny, but the wind dropped, so at times we were only making 2-3 knots.  We continued bobbing along until midnight, when a huge black system approached and sucked all the wind away, forcing us to start motoring.  Fifteen minutes later, we had over 20 knots of wind, then fifteen minutes later we were motoring again.  This happened a few times during the rest of the night.


By 0300, we were 20 miles from the entrance, motor-sailing slowly.  There are no navigation lights on this low lying atoll, so even though we've had reports that the charted position is accurate, we decided to keep a healthy five miles offshore until dawn.


I've been pondering why we always seem to arrive at the end of long passages at night or have to slow down to avoid arriving at night.  If we say that the best time to enter coral-strewn waters is between 0900 and 1500, then that's only a 6 hour window.  So there's only a 25% chance of making a perfect landfall. 


If we average 5 knots on a 600 mile trip, then that works out to 120 hours (5 days).  However, if that average speed changes by 1/2 knot, then the passage time could be between 109 and 133 hours - that's a massive 24 hours difference for a tiny change in speed.  There's obviously no point in trying to plan - we should just leave when we're ready and accept that there's a 75% chance that we'll have to heave-to or slow down to wait for dawn.