Post by fish on Nov 11, 2022 16:27:57 GMT 12
For those listeners in Auckland, or at least around Whangaparaoa, it appears we have a sea fog. Slight breeze with poor viz in a mist / fog like thing. Predict Wind has been forecasting one for tonight, and I was a bit like 'whatever'.
I didn't think we really got sea fog's in NZ. More of a UK kind of thing, where you can get a pea-soup'er for weeks.
I'm just trying to remember the technical difference between the two fog's. What is it? an advection fog is what you get at night / early morning, where you have warm air trapped at ground level by a cold layer of air above it. Only ever happens on clear calm nights.
The sea fog is so uncommon, I get mixed up which way round it goes. Is it warm moisture laden air over colder water? or is it cold, moisture laden air over warm water?
Either way, I know it is a major hazard to navigation and otherwise referred to as a major pain in the arse if you are on a boat. About the only way to deal with it is with radar. When I was training in the UK, back in the day, pretending Vlad had taken out the GPS system and a fog descended, we would have to do blind navigation exercise to get into a safe harbour. Things like range and bearing from your last confirmed position, tidal set and drift, using a depth sounder to find a contour line on the edge of a channel and stooge along until you picked up channel markers etc. Was a lot of fun. Dyeing art these days with GPS and broadband radar.
True story.
Coming back to Portsmouth from a RORC race to the Channel Islands one weekend, it was a drifter. We ran out of diesel in the shipping lanes, and a sea fog came up. We were shitting ourselves. All on deck in LJ's, put the storm sails up as there were bright orange, basically ready to jump overboard if a ship didn't weave around us. The skipper was broadcasting a securitee to the shipping in the hope we wouldn't get run down. The boat that won our division was listening and came back to give us a tow. Very embarrassing. The boat was a Sigma 38, built like a battle tank, one design in heavy GRP, loved racing that boat.
Two weeks later, coming back from the next race, we were in a similar situation, weather wise (no wind) but this time had plenty of diesel. An old guy was out solo sailing in the Solent. His engine wouldn't go and he had been trying to sail back to the Hamble all Sunday. About 11pm Sunday night he put out a Pan Pan, so we went and found him, drifting in the dark amongst anchored freighters, took him under tow and got him back to the Hamble. He was very tired and blind as a bat in the dark I think. Was very worried what his missus would say about him being so late home...
I was having to plot his position as he was getting washed out east on the ebbing tide, and set up an intercept down current to locate him. Worked first time, was very pleased with myself. One of our crew was late for work on Monday and missed a very important meeting, but having had our arse saved the race before, I couldn't see how we could leave this old guy drifting up and down the channel as we motored home.
I didn't think we really got sea fog's in NZ. More of a UK kind of thing, where you can get a pea-soup'er for weeks.
I'm just trying to remember the technical difference between the two fog's. What is it? an advection fog is what you get at night / early morning, where you have warm air trapped at ground level by a cold layer of air above it. Only ever happens on clear calm nights.
The sea fog is so uncommon, I get mixed up which way round it goes. Is it warm moisture laden air over colder water? or is it cold, moisture laden air over warm water?
Either way, I know it is a major hazard to navigation and otherwise referred to as a major pain in the arse if you are on a boat. About the only way to deal with it is with radar. When I was training in the UK, back in the day, pretending Vlad had taken out the GPS system and a fog descended, we would have to do blind navigation exercise to get into a safe harbour. Things like range and bearing from your last confirmed position, tidal set and drift, using a depth sounder to find a contour line on the edge of a channel and stooge along until you picked up channel markers etc. Was a lot of fun. Dyeing art these days with GPS and broadband radar.
True story.
Coming back to Portsmouth from a RORC race to the Channel Islands one weekend, it was a drifter. We ran out of diesel in the shipping lanes, and a sea fog came up. We were shitting ourselves. All on deck in LJ's, put the storm sails up as there were bright orange, basically ready to jump overboard if a ship didn't weave around us. The skipper was broadcasting a securitee to the shipping in the hope we wouldn't get run down. The boat that won our division was listening and came back to give us a tow. Very embarrassing. The boat was a Sigma 38, built like a battle tank, one design in heavy GRP, loved racing that boat.
Two weeks later, coming back from the next race, we were in a similar situation, weather wise (no wind) but this time had plenty of diesel. An old guy was out solo sailing in the Solent. His engine wouldn't go and he had been trying to sail back to the Hamble all Sunday. About 11pm Sunday night he put out a Pan Pan, so we went and found him, drifting in the dark amongst anchored freighters, took him under tow and got him back to the Hamble. He was very tired and blind as a bat in the dark I think. Was very worried what his missus would say about him being so late home...
I was having to plot his position as he was getting washed out east on the ebbing tide, and set up an intercept down current to locate him. Worked first time, was very pleased with myself. One of our crew was late for work on Monday and missed a very important meeting, but having had our arse saved the race before, I couldn't see how we could leave this old guy drifting up and down the channel as we motored home.
