Fog in the Solent

Saturday started as a very sunny day, so I took Salar out for a long-overdue fishing trip. Or so I had planned. We left Langstone in bright sunshine and headed to Dean Tail to catch a few mackerel for bait. Within minutes of arriving at the edge of the shipping lane, the Isle of Wight ominously disappeared, followed very quickly by everything more than a few yards away. Very creepy, it all happened in the space of just a few minutes and would have been very scary without my trusty chartplotter.

Fog can cause total disorientation with no landmarks in sight, but the wind was still at least F2 so I had a constant wave direction to give some sense of direction. However the GPS signal was still spot on so I knew exactly where I was, not in the shipping lane but probably a bit too near to be safe. I was a little concerned about the smaller coasters that may have slightly wobbly navigation. The AIS function is a godsend in these circumstances, and I am now a convert to the Class B signals. I used to be very scathing about the class B leisure craft transponders because we see so many bleeping away from marinas where owners had clearly forgotten to turn them off, and I thought that to fill the Solent with bleeps would hide the ones to really worry about, Class A bleeps from the likes of the Queen Victoria.

Anyhow, back to the fog story - I was keeping a very watchful eye on the plotter and the edge of the fog about 100 metres away when I received an AIS alert for a vessel heading straight for me - outside the shipping lane. Time to skedaddle I thought, then I noticed the speed indicated - 4.4 knots. Even a rusty coaster does twice that. It must be a sailing boat, and sure enough I just managed to glimpse a large yacht in the gloom. I pulled out my Plastimo aerosol foghorn (loud enough and cheap) and gave it a good hoot in the general direction, and it glided by at a safe distance. So Class B does have a place - particularly when I'm fishing in the fog!

Seeing ships on your chart plotter

I have been watching ships in the Solent area on web pages just for fun while I was at home, without realising that the same AIS (Automatic Identification System) technology can plot those ships on your own chart plotter on your boat. How handy is that? Better yet, it costs under £150 for the parts, and gives more shipping information than radar costing more than ten times as much.

I recently fitted a NASA AIS engine to pass AIS signals to my Garmin chart plotter - more information and a "how to" guide is on my Boat Angling web site . I reckon it is a huge, and relatively low cost, addition to safety at sea. Most of us worry about being run down by large commercial craft who don't see us at anchor, or if we break down in a shipping lane. With detailed information on the vessels name, heading, speed and MMSI number displayed on the plotter, you know exactly how close it will pass, and if you are concerned you can dial in the MMSI number on your DSC VHF radio and a talk directly to their bridge. The chart plotter and AIS engine will not drain the battery like a radar will, so you can afford to leave it on, which has another benefit. You can set a safety zone around your own boat, and an alert will sound if the plotter detects that a ship is encroaching on that space. Handy if the fishing is good and you haven't had a look around for a while!

As an example, this photo is a screen shot of the very first alert that sounded when I connected the system up. The dredger Donald Redford is heading out of Langstone at 7.5 knots, and has entered the 0.2 mile radius "warning Zone" that is centered on Salar which is sitting in Southsea marina. Hardly a danger, but it proves a point. I didn't even know it was there.