Thoughts on our lightning strike

Now that we have put Lyra back together again I thought it might be worth putting down some thoughts as to what happened in our strike, what we do now to minimise being hit again and other lightning related stuff.

When we were hit in June we were in our home marina with 180 other boats around us. It was an intense and obviously very local storm that lasted for around one hour. We were the only boat struck that day. Our mast was the tallest on our pontoon, but far from the highest in the marina. It just comes down to luck and we were unlucky that day. We were on board when it happened and Jan saw a big flash at the mast, there was a strong smell of ozone and then a smell of melting plastic. The instrument panel had flashed on and then off. We stood dumbfounded and waited for anything else to happen. Nothing did and when we lifted the sofa cushion to look at the electronics we could see that the voltage sensitive relay was pretty well melted- that was where the smell was coming from. We switched everything off and waited for the rain to stop, fire extinguishers at the ready. 

We had used a local electrician (Kostas Limnios, Kalamata-highly recommended) for a small repair to the windlass remote cable a few days before this so we called Kostas to come and help us investigate. We restored shore-power and he checked the batteries. Our initial estimation was that we had blown up the VSR, engine electronics and the battery charger - at this stage we didn't want to get into the instruments side of things. I had a spare MDI for the engine so we fitted that and were able to check the alternator- that worked fine. Having a qualified electrician on-board really helped steady the ship as the skipper flapped about a bit, imagining how much worse it could have been, especially if it had happened at some remote spot.

I contacted the insurance company (Y Insurance, UK- another recommendation from me, they handled the whole issue promptly and effectively) and they appointed an assessor based in Athens They sent an initial investigator down to have a look at things. He took up floorboards and stuck his head down into the bilges. I asked him what he was doing and he said he was smelling for lightning. After he had checked the bilges and the shrouds and the mast base he said he was happy that the strike was not structural and was limited to electrical equipment. He told us how lucky we were. Kostas and I put together a list for them of equipment we knew to be broken and equipment we thought to be be damaged. 

I started to ask questions of knowledgeable friends and used the internet for more research. The basic conclusion was that everything electrical that contained a printed circuit board was likely to be damaged and would need replacing. I asked the assessors to bring a specialist electronics team to survey the boat and they did so, Naveltec tested everything and recommended replacement of all of our B&G electronics. The lightning had hit the boat at the VHF aerial, completely destroying that, run down the coax cable to the splitter, then to the AIS, then along the data and power cables destroying instruments and engine electronics along the way, before exiting. Some 200,000 amps for a fraction of a millisecond, jumping every fuse bar one on board. All of the house electrics, lights, fridge, bowthruster, windlass were undamaged as were all of our personal electronics.

The electronics team tested all of the data and power cables (which were all fine) and replaced all of the cable junctions (there are lots on a N2K system). We had to replace the plotter, cockpit instruments, autopilot computer, fluxgate compass, speed & depth sensor, wind sensor, AIS and splitter, 12v instrument panel, Volvo cockpit control panel and MDI, VHF aerial, battery charger and stereo system. Only the VHF (on a different data leg after the splitter, remains from the original B&G equipment). Lesson 1- get specialists to inspect sensitive electronics not local electricians.

The Greek teams were all knowledgeable and committed to doing a good job. Everything took a long time- as it does in Greece. I realised later I could have reduced the delays if I had agreed to pay up front for everything- money is so tight in Greece that no-one wants to be holding debt, especially if they suspect the bills will take a long time to be paid. Lesson 2- pay everything upfront and claim it back personally. 

Once we had tested everything, re-configured the system and test sailed the boat, we realised we had a continuing problem with the depth sensor as it produced phantom alarms when in very deep water. It's a problem of our torpedo keel and a firmware fix from Airmar should fix that problem. 

I have read lots about trying to prevent strikes and there's not much that can be done. Our new routine is
1. Disconnect the coax aerial cable from the splitter when leaving the boat for any time or when lightning is around.
2. If at sea or at anchor, switch on the engine. I'm told that even if the MDI is then destroyed the engine will keep running.
3. Use www.lightningmaps.org or similar to get real-time info on lightning strikes
4. Put portable electronics in the oven
5. Cross fingers.

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just some of the broken electronics