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Friday, 07 December 2012 04:45 |

Written by Administrator

“Bastion” was at sea for a total of ten days. The equivalent of one day was in the lee of land – the coast of New Zealand. Seven days were rough weather. One day was flat calm.

The voyage statistics are:

Total main engine hours 252
Generator running hours 140; we did not connect to shore power in port.
Total fuel burned: 6550 litres
Total genset fuel @ 3.75 lph 525 litres (included in above total)
The main engines burned 24 litres or approx. 6US gallons per hour.
This indicates that the vessels main engines were delivering 69 BHP each.

These figures tell us that 138 BHP, slightly less than half the continuous rated capacity of the engines, pushed a 68.6 ton weight over a distance of approx. 2000 miles at an average speed of 8.5 knots, consuming 5.5 ton of fuel - that demonstrates economy!

The first video is the outward bound leg. The wind is from the North West, on the port bow and “fresh to gale force”.

The second video is from the return leg. Our course is South East, the wind southerly. This was caused by the large 1027mb “high” centered on the Tasman Sea and a “depression” just to the north of New Zealand. These can be seen in the isobar picture below. A large high always has a lot of wind around its perimeter. The higher the high, the stronger the wind will be. This one was more or less stationary, whipping up a lot of cold wind out of the south.Over three days we had 30-35 knots with one afternoon and evening of 40 knot winds with what I judged to be a 6-8 metre (18-24ft) swell.

The satellite image below shows surface wind speed. The red spot just to the north of New Zealand indicates 35knots of wind. We had three days of this with an afternoon and evening of 40 knot winds with what I judged to be a 6-8 metre (18-24ft) swell.

When designing our hull form we incorporate a high degree of “sea kindliness”, using time tested formula that includes high, refined bow sections with fine angle of entry at the waterline along with high propulsive efficiency provided by adequate draft and large slow turning propellers; this combination gives the “staying power” demonstrated in these videos.

I have kept the horizon in view so as to give a better indication of the motion of the vessel. As you can see the rolling and pitching motions are minimal.

At no time did Bastion take “green” water aboard; even her transom boarding platform remained relatively dry. Green water is the most dangerous; something I will be writing about here soon.

1 comment links tpl

Last Updated (Monday, 10 December 2012 09:24)

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