Aurora_b's Web Diary - Sea Trials!

Sea Trials!

Aurora_b

Mike and Liz Downing

Sat 10 Mar 2012 11:47

Had my first swim this year, in fact my first swim for almost a year. It wasn't for the joys of swimming in the sea, but to check the growth under the boat and give it a clean! All manner of marine creatures thrive here and our dynaplates (2 honeycombed metal plates for grounding the long range radio) cannot be antifouled and are unprotected. Not having moved much since being back in the water, it was highly likely that mussel beds would be well established on both. It was a pleasant surprise to find quite a bit of weed was growing, but nothing with a hard shell. So it was not too difficult to take deep breath and dive under to give each a good scrub. It was good to get back in the water and it wasn't too cold, but that could have been due to the 7mm semidry wetsuit!

We like things to be exact and repeatable - something either works or it doesn't. Sometime it's just not like that. Our next sea trial confirmed that the new freshwater pump was okay, but threw up 2 new issues. The engine tachometer threw a wobbly by going round to full scale and staying there, twitching for an hour, regardless of the actual revs of the engine. At the same time the backup GPS decided not to find any satellites, even after an hour of searching (it normally takes a few minutes). Back on the berth, the engine was switched off and on and the tachometer worked fine. The GPS was unplugged from the external aerial and taken outside to find satellites using it's own internal aerial. Still, no success, but an hour or so later it found a satellite, then two and then a load. It was working again. Plugging it back into the external aerial it still worked. It's been started most days since and it's still working.

Next task was to bring the Mastervolt diesel generator back into service. It hadn't been run for almost 12 months, so fuel filters and the sea water impeller were changed. (The oil and oil filter had been changed before the lay-up last year, so it had been sitting in new oil). It started second go, but no sea water was getting through - was the new impeller not working? Happened to be talking to be the Mastervolt agent here about spares and discussed the problem. Clearly we had a blockage somewhere, perhaps the heat exchanger was blocked. It's not easy to even find the heat exchanger and near impossible to get it out when you do. This didn't look good. A day later, all prepared for a long investigation, water now appeared to be getting through where it wasn't the day before. So it was worth a try, and it started, and yes, sea water was getting through okay. It was working fine. The explanation, we think, was an air lock formed during the lay-up and this had worked it's way out during the day between starts. So far there's no explanations for the GPS and tachometer.

Sailing at last! The next sea trial earlier this week, finally took us out of the harbour to the open sea. After 10 months of living on board in the marina or ashore, it had taken a couple of days doing nothing but stowing gear in safe places, so we could heel without fear of the contents of the boat shifting from one side to the other and back again. The wind overnight had thrown up a sloppy onshore swell that did it's best to upset our stomachs and came close to succeeding, but it didn't and the sails were up we were away, doing 6 to 7kts into light north easterly. The current through the marina runs so fast that it's best to leave and return at slack tide. So unless it's only a short test (an hour or less), it's best to stay out for the length of a tide and so it was our first afternoon out sailing in the Bay of Plenty, checking everything out. As well as the sailing gear, it also gave the opportunity to test the radios and navigation equipment, particularly the radar, which on certain headings showed the coast to be at 90 degrees to where it actually was - a little disconcerting! A misaligned compass heading seemed a possibility, so on the way back in we decided to have a go at swinging the fluxgate (electromagnetic) compass which supplies heading data to all the navigation instruments we have. This seemed to clear it, but where previously we had a magnetic deviation of only 1 degree, it was now 15 degrees. So we did it again, going round in circles (which you have to do) and confusing another boat who must have thought we were nuts, but the result was still the same, 15 degrees. This is too big for comfort, so it was another sea trial today to experiment moving things about where the compass is located to see if it made any difference. And when the dehumidifier was moved, it did. It was bought here and stowed just the other side of the bulkhead from the compass - out of sight of the compass, but actually only a few inches from it. Moving it 1 metre or more away and, after several more circles, the deviation was back to just 1 degree again. We've just got to find somewhere else for the dehumidifier to go when underway, and that's easier said than done!

The weather continues to do its darnedest to make it a miserable autumn, following the miserable summer. This time it was a weather bomb! Not a term we're that familiar with, even having spent 3 1/2 years where the weather is the most important news of the day. It's where a low deepens, i.e. pressure drops, 24 millibars or more in 24 hours and we had one last weekend that came across the North Island from the Tasman Sea. The net result was heavy rain and very strong winds - in the marina we recorded 47kts on the Thursday and 43kts on Saturday. The west coast had worse and loads of power lines came down. We're hoping for an Indian summer, but not holding our breath!