Preferred method if caught in a t-storm

[bsangs]

Have been fortunate so far to not hit any heavy weather while cruising, but that could change this week as I host some friends for five days cruising the Long Island Sound. As if often the case during summer around here, forecasts call for afternoon thunderstorms each day. Fortunately, there is no shortage of bail out marinas and anchorages in the area we’ll be traversing. Still, the possibility exists we’ll be caught in one or two.

So wondering what people’s preferred method of handling a thunderstorm is? Not talking basics like don’t touch metal, don’t use the VHF, put electronics in the oven, etc, more interested in sail tactics. I’m thinking best method is just dropping sails and motoring through, or away from it, if it’s isolated. Those t-storm winds can be strong and unpredictable, so figuring safer with no sail up. That how the Ericson crowd would handle it too?

 

[Christian Williams]

On thunderstorm days--and weather reports predict them pretty well--most develop after 4 p.m. On the Chesapeake, in such days days in summer, it is good to be back at the dock by then.

A typical thunderstorm has a 60-knot gust front proceeding it. They can and do move against the existing wind, which may be nearly nonexistent.

Sometimes, on a sultry day nearly becalmed, it's hard to get out of the way. It is quite arresting to watch a towering black mass proceed directly toward you, signaled by thunder, and then observe the line of white froth preceding it. All while becalmed.

Lower sails and secure them. Anchor if practical. If not leave a scrap of jib, suit up, and prepare to steer for a wild ride. Most pass in 20 minutes, providing a memorable event of lightning and thunder, heavy rain and possibly hail. With sea room, a story to tell. Maneuvering into a slip or in a crowded anchorage, to be avoided.

When the sky begins to rumble, or in anticipation well before, head home.

Despite the giant lightning rod of a mast overhead, few boats are struck. It does happen, but I don't take special precautions. We used to carry jumper cables, to dangle into the water from the stays. They were so rusty I threw them overboard in the middle of a meteorological event 100 miles off the New Jersey coast that was characterized by exploding bombs of lightning all around us in a driving downpour that lasted hours, becalmed the whole time and punctuated memorably by sonic booms from the Concorde (we deduced later). What the hell was that!

 

[Bolo]

As a Chesapeake sailor by far the best thing to do is to consult the marine forecast the morning you plan to sail because in the summer months it seems that things change quicker and more often than say in the winter or fall because summer weather is more “dynamic“ IMO. I‘ve been caught in a few bay storms in my day and found it best to reduce sail and move to an area where there are few obstructions (bridges, docks, large metal channel buoys) because storms will push you around and visibility becomes an issue. Definitely do not attempt docking in a storm. A dock neighbor did that with his boat last year and nearly wrecked it even with the help from five wet dock neighbors with one of them being me.

Even in a “safe” anchorage with good holding bad things can happen. Years ago, when I owned a Hunter 285, we anchored in Fairlee Creek just off the bay, which is usual a well protected anchorage. About an hour after throwing the hook down I looked to the west and saw a massive black wall of clouds pushing the white lower clouds out of the way. It almost looked like they we being eaten. I remember seeing flocks of white seagulls contrasted against the looming dark wall heading our way. We removed everything we could topside, let out more anchor rode and went below.

When the storm hit us instantly there was a complete “white out” accompanied with a screaming wind. I could barely see the bow on our 29 foot boat. After about ten minutes, when we could see again, I went topside to see that we dragged our anchor more than a half mile. So I started the engine, got my first mate behind the wheel and instructed her to motor up on the rode while I pulled it in. Of course now it was still pouring. As I pulled up the anchor rode I felt no resistance and figured that the chain, of the chain/rope rode, had parted from the fluke anchor I was using back in those days. (I know more about anchors now so a fluke in not my primary anchor.) To my surprised my fluke anchor appeared but it had a bigger than fist sized stone wedged in between the flukes! It was stuck so firmly that I needed a hammer to release it. The stone prevented the anchor from flipping and resetting during the big blow. Anyone who knows the Chesapeake Bay knows that most of the bottom consists of one thing. MUD. So to pickup a large brown rock with my fluke anchor was….well….a real fluke.

 

[Vtonian]

Interesting use of jumper cables, Christian. I think I have a spare set...

FWIW, I did a fair bit of research on what causes lightning because I have a client whose network gear has suffered from several lightning strikes near to his house on a bluff. I had a theory that there must be something to do with the prevailing winds bringing charged clouds overhead that, as they got past the bluff and their distance from the ground would suddenly increase, would release their charge like a set of points opening up on an older gas engine. I ran across this video from Emily & Clark's Adventure that has the easiest to understand explanation of what causes lightning (including simple animations) and how to protect your boat: LIGHTNING Hits Boats. Here's How to Deal With It, in case anyone is interested.

Apparently it's a controversial subject. I'd love to hear opinions from others with real world experience in lightning prone areas about protecting your boats. It's on my to do list and I haven't yet seen anything about Ericson's standards and methods for bonding. I haven't noticed any big straps running through the E38's bilge...

My apologies if this is a thread hijack, but, jumper cables, c'mon, that requires some follow up.

 

[gareth harris]

I looked into the subject before I took my boat to Pensacola, where I experienced some of what has been described above but not to such an extreme level. In Pensacola Bay it was always possible to find a shallow enough point to anchor, which was what I did. I put up a discussion of choices of anchor on this site about fifteen years ago, and fluke anchors were not popular for similar reasons to Bolo's, although none of the stories were quite as good as his.

It is essential to ground the mast in an area prone to lightning (Ericson did not build it in because California only has storms inland). From a deck stepped mast that means the thickest copper wire you can find attached to the mast and run straight downwards through the cabin to a copper plate under the hull. I never like drilling through the hull, but without a path to follow the lightning may make its own hole.

There used to be a firm in Canada which made a mast attachment with two thick electrical cables to large metal grounding points suspended over each side of the hull. I do not know whether it still exists, I couldn't find it the last time I did an online search. It was much easier to use than installing grounding, but having loose heavy metal grounding points banging around next to the hull in a storm is less than optimum. Some people use jumper cables for the same effect but I think they would likely disintegrate so quickly when struck by lightning that they would not fulfill their role.

There is some question as to whether to build a Faraday cage around the boat. Some sources recommend running 8AWG wire under the perimeter of the entire deck, and connecting it to the forestay, backstay, and shrouds, and then from all of those four points running another 8AWG above the hull to the copper grounding plate under the mast. That will provide protection to the crew from the strike since there will be a path for the lightning all around them, but has the risk that the lightning may make a path from the 8AWG to the water which does not go through the grounding plate, which could blow a hole through the hull. Lightning is unpredictable.

Finally, there is a question as to whether to use a static dissipator, which looks like a brush sticking up, on the top of the mast. They are used on tall buildings and towers with the intention that the static electricity which builds up in the ground during a thunderstorm dissipates into the atmosphere too quickly for it to reach a level that it attracts lightning. My concern on a boat is that so much electric charge can accumulate in the mast from the ocean, itself full of moving electric charges, that it is impossible to dissipate it, and indeed creating too many ions right above the mast might even attract a strike. I am however told that a dissipator is great for preventing birds from sitting on the mast.

Gareth
Freyja E35 #241 1972

 

[Vtonian]

I went back and read comments in the YT I linked and found a few more references to jumper cables. Your mention that they might not do the job because of their construction is also confirmed.

In other comments, it's suggested to wire ground paths in straight lines, especially avoiding 90deg turns, due to it following the path of least impedence. My analogy for it is lightning is more like a fire hose with a pressure washer nozzle on the end and is blasting directly through to its target, detours be damaged.

That said, my philosophy in general is, don't be the low hanging fruit. If there's a simple solution that addresses most cases, that's probably easily worth the cost and effort.

From battery building DIY, where solid copper straps are used instead of stranded wire for the same reasons, and a cheap strap alternative is to pound a piece of copper pipe flat, I'm thinking maybe taking a 10ft shot of copper pipe, flatten it, fasten something like a jumper cable clamp on the end and trail it in the water from the backstay. That would meet a number of the criteria with not much cost or effort.

I think adding some quick disconnect fittings to the solar panels is going to be part of this too, if I intentionally route lightning right down between them.

 

[Dave G.]

I am not sure if there is a way to mitigate a direct lightning strike. I've seen a couple of boats that took strikes to their mast and or rigging. One sunk in it's slip due to the holes burnt through the hull. That was a Catalina 42 with a solid layup hull. All the electronics and wiring were toasted, the deck at the shrouds/chainplates was black and deformed. One of the cap shrouds was severed and laying on a neighbor boat. There were 6 people on board when it happened and all walked away without a scratch miraculously. I looked at the hull when they pulled the boat and there wasn't any rime or reason to where the lightning exited into the water. Just dozens of holes some bigger than others. Best to dock next to boats with taller rigs and stay out of thunderstorms

 

[gareth harris]

From battery building DIY, where solid copper straps are used instead of stranded wire for the same reasons, and a cheap strap alternative is to pound a piece of copper pipe flat, I'm thinking maybe taking a 10ft shot of copper pipe, flatten it, fasten something like a jumper cable clamp on the end and trail it in the water from the backstay. That would meet a number of the criteria with not much cost or effort.

I think adding some quick disconnect fittings to the solar panels is going to be part of this too, if I intentionally route lightning right down between them.

The two problems with hoping the strike will go down a stay are firstly that the mast is a far better conductor than the much thinner stranded cable, and secondly that if the stay fails after the strike then the mast will fall.

When you watch lightning in the sky you see its path follow the random nature of ion formation in the atmosphere. It is impossible to make a path it will definitely follow, one story I read when I was researching the subject was of a ketch which was struck on the mizzen mast despite it being the shorter of the two, then following a path all the way forward through the deck to the anchor rode. The best you can do is to make the intended path a much better conductor than any other, hence grounding the mast to the water directly beneath it.

Dave's observations are exactly those I read about happening in ungrounded boats, luckily I have never seen it myself. When I was sleeping at the marina and was woken up with a hangover by a thunderstorm I could take heart in having a grounded mast and the fact that there were more than two hundred other boats around me most of which had taller masts than mine.

Gareth
Freyja E35 #241 1972

 

[Pete the Cat]

I suppose none of us has a lot of experience to draw on when it comes to lightning. I carried jumper cables in my cruising years and deployed them a couple times but have not been struck in several thunder storms. I recall spending a tense day in the offshore Western Caribbean watching the clumps of T-storms all around me--in real and radar, and seeing the lightning strikes on the water all around, but at a distance. I was never hit. From that one experience, I unjustifiably concluded that it seems like the old idea that lightning seeks the highest metal must not be true and that being hit is more a matter of luck than being able to prevent or manage it.

 

[frick]

Had a friend in Texas who had about 6 feet of stainless chain attached to his back stay. When the T-Storms were upon him that Chain was dropped in the water. I think he "launched" the chain when he was out of town just in case.

Most old boats have no lighten protections.
New Boats have everything grounded created a faraday cage of protection.

 

[Drewm3i]

I wrote an article for Good Old Boat in May of 2022 entitled: "Lightning and Sailboats," that discussed anecdotal results of numerous strikes to friend and acquaintance boats in Florida during 2018-2019. I knew about 5 couples/boats and of the 5 including us, 3 were struck in those years. One was an Endeavour 42 named Bonzee with an encapsulated keel that was grounded to an external plate. One was Sailing Soulianis, a Tartan 37 with a centerboard from the Great Lakes, so I'm not sure if it was grounded.

Our boat, an E-38-200 named Walden that sank in early 2022 off Florida after she was sold to another forum member, was struck before we bought it in 2018 with a side strike. It was the vessel's second strike, neither of which caused any major discernible damage. The boat did develop lots of blisters after the first strike however and our surveyors anecdotally claimed the lightning possibly contributed to it because it vaporized the resin--his words, not mine. The boat was not grounded until I bought it. It did have a dissipator fitted (but not grounded) after the first strike. We did also have a u-bolt chainplate break on our first and only offshore passage. I caught it in time thankfully, but do wonder if the lightning strikes helped damaged the stainless hardware.

All of the boats had electrical damage to the 12 volt side. Ours had very little damage and was basically the VHF and instruments only. Bonzee had its entire DC electrical system wrecked with breakers welded in the middle position. Soulianis had minor damage if I recall correctly.

I would definitely recommend grounding the mast to a keel bolt at minimum with the largest tinned copper wire one can find. Side flashes inside the cabin to tanks and such would worry me a bit with people onboard. Beyond that, you could look into TVSS devices (which I installed on Walden) and a gas-block surge protector for the VHF coaxial cable.

I hate lightning.

 

[bsangs]

Well we successfully skirted the t-storms that rolled through Oyster Bay, and a day earlier smartly tucked into City Island about a half hour before sustained - and non-forecast - winds of 25-35 knots turned our mooring area into a rollicking 20-hour wave pool. Certainly strengthened my belief in the power of a good mooring ball. Great few days on the Sound.

 

[gareth harris]

I forgot to mention that it is worth carrying a metal box, some people use the oven, to act as a Faraday cage for storing electronics inside when a storm is approaching. It needs to be big enough to hold the VHF, GPS, navigation readout, cameras, etc.

Disconnecting the VHF from a masthead antenna is a good step too.

#Gareth
Freyja E35 #241 1972

 

[Bolo]

I forgot to mention that it is worth carrying a metal box, some people use the oven, to act as a Faraday cage for storing electronics inside when a storm is approaching. It needs to be big enough to hold the VHF, GPS, navigation readout, cameras, etc.

Disconnecting the VHF from a masthead antenna is a good step too.

#Gareth
Freyja E35 #241 1972

I once read that just stashing them in the on board oven does the same thing.

 

[Randy Rutledge]

Lightning, not hit, but 92 mph wind, two minutes later boat was headed to the bottom. Should have had the mast grounded.

I have been lucky/ blessed to never had a lightning strike, storms in Pensacola, Keys, East coast of Florida and on Weiss Lake NE Alabama. A friends Gemini cat was hit in Panama City FL was hit at the dock splattered the vhf antenna and got all instruments and vhf.

Our marine on Weiss Lake with 60 slips all sailboats has had no strikes in the 24 years I have been in the club. Just had a storm pass through, think I will go check my boat.

 

[frick]

What I used to do... Get a slip near another Sailboat with a very tall mast.... Live in the cone of protection

 

[bsangs]

What I used to do... Get a slip near another Sailboat with a very tall mast.... Live in the cone of protection

How’s that work? “Roger that. Only I’m not taking the assigned slip. See that 75 foot sailboat over there? Ask the people next to her to move. I’m tucking in there.“

 

[David Vaughn]

We got lucky at our previous marina. We were right in the middle of all the race boats with their tall rigs.

Some friends came to visit and it started pouring rain as they arrived. We met them up at the clubhouse and as we waited for the rain to finish, one of them asked about storms. From where we were on the hill, I pointed and said “see all those tall masts way above the top of covered docks? Now, look just barely above the covered dock, third one from the right with the green cover. See how short that mast is? That’s us!”