Passage Planning

Vega
Hugh and Annie
Wed 19 Jan 2022 05:12

Just when we were thinking there was nothing left on Vega that could conceivably need maintaining or repairing we were informed there was a problem with the stern tube and it needs replacing. Having spent the best part of four days removing and then replacing the prop shaft the engineers discovered that the stern tube has corroded - see photos. The stern tube is moulded into the hull and through which the propshaft and its cutlass bearing and water seal are located. The stern tube can be brass, stainless steel, fibreglass or anything really. Whatever it is removal is a pain because the internal hull into which it is moulded may need to be cut away in order to release the tube. At one point the engineers were planning to replace ours with a fibreglass tube (corrosion free) but we are now pursuing “plan C” - a copper nickel tube. Search me what plan A was or why we have gone from fibreglass back to a metal tube. The new tube plus bronze attachment point for the cutlass bearing are being machined and epoxied together this week.
My woes are compounded by the fact that we need both a new cutlass bearing and water seal. You may recall I had the option of paying less for a seal through the main distributor here or more from another supplier but with a quicker delivery time. I opted for the quicker delivery and soon came to bitterly regret taking this at face value. The main distributor would have ordered last Tuesday and then invoiced me. The “quicker” supplier didn’t order until the money was in his account on Thursday which meant there was never a chance that the delivery would be any quicker. Furthermore DHL is showing a delivery date of 24th January - a week later than might have been the case with the main distributor. My fury with the supplier is only tempered by my own stupidity for not seeing the folly of taking the unlikely prospect of an earlier delivery. The latest from DHL is showing the parcel has gone from Nova Scotia to Quebec to Cincinnati to…………….
East Midlands airport!! It’s now on its way to Leipzig. I couldn’t have made this up. The supplier is now offering profuse apologies and vouchers to spend in his stores.
Once back on the water we still have e reduction in freshwater cooling level for the engine to investigate plus what appears to be an oily leak from the newly refurbished seawater intake pump.
So, for the time being We can only complete the tasks we have away from the boat and continue to run passage planning models to see how things are looking for sailing to the Maldives at the end of the month. Plus a lovely walk in the rainforest organised by Annie.
There are several weather forecasting software packages available to yachties. We use PredictWind but there are others such as LuckGrib and Windy. Each will give a weather forecast for free as a grib file for creating animated weather maps on a laptop, tablet or phone. For planning passages you can buy or subscribe to upgraded software that will plot a course based upon chosen weather parameters, sea conditions and boat performance or “polars”. They will even tell you the best day to start your passage for your chosen parameters. Of course you can work this out for yourself given an accurate forecast and you can also choose your forecast provider - the European model has a good reputation. Having software to do it allows an enormous number of calculations to be done very quickly but even then, to save the cost of data at sea, manual updating will be required along with each updated weather forecast.
For the passage from Thailand to the Maldives the two best months are January and February when the prevailing NE trade winds are blowing. The wind is often lighter in February so a start between mid and late January is favoured.
The models I have been running show a passage time for January of around 10 days; 12 days if we choose not to motor at all. This goes up to 14 days for passages in February and the trend, true to form, is for progressively lighter wind. This is one reason why a further delay of a week is a pain because we would like to conserve fuel on the passage, saving it for the likely windless conditions in the Maldives.
So, if the new shaft seal arrives on Thursday as the supplier hopes we can be back on the water at the weekend and out of here the week after. If it doesn’t come until 24th we lose any opportunity to explore the west coast if we leave Thailand before the end of the month. We will be sailing at the same time as friends Colin and Izzi on Endorphin Beta (he’s a surgeon as you might guess from the name of their boat) and Jon on Hecla. They both have ongoing maintenance issues and are coming into the marina on Thursday for more work on their boats. Another boat Alcedo of Rhyme has been here for nearly two years during lockdown. The owners have returned and were hoping to cruise locally before shipping the boat back to Europe at the end of the month. They have now found a number of problems including the corroding through of the interface between the freshwater expansion tank and the exhaust manifold resulting in the freshwater leaking into the exhaust! We are not alone!

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Spot yesterday’s job for Annie and me


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