One of the things that we have improved on is our passage planning technique. At first, when we were just doing day passages in the Caribbean, it was difficult to estimate. So we would set off early in the AM and beat until we got there.
Now we are a little more technical.
If we are doing a long passage departure and arrival time are less important, however we still apply a general rule. We cruise comfortably at about 5.5 knots with a 15 knot trade wind on the quarter which is normal in the South Pacific.
Our workings:
1. We work out the rhumb line using OpenCPN (a free easy to use computer programme).
2. If we are beating, we generally over estimate the actual miles we will travel by 30-50% depending on the wind / wave. This is based on past experience (and factoring in comfort while at sea etc). If we are running, it is as little as 5% extra.
3. If we do a fast comfortable passage at 6 knots (remember we are cruising not racing and never push the boat) we would want to arrive at 7am. This allows us a full 11 hours if we slow down to get into the anchorage in daylight. We also work out what time we get in at 5.5 knots average and 5 knots average.
4. Wind has an uncanny ability to drop just when you need it most, as such we tend to only slow the boat down in the last 24 hours. Sometimes in very high wind and wave, an almost bare pole Orion can still be cruising along at 4+ knots…
It is most certainly an art not a science and each boat is different but this seems to work for us.
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