Dangers of thunder storms

[DAKA]

Any one know if thunder storms present much of a danger ?
they seam to be increasing and follow a nice sunny settled period *


Several years ago I was crossing the Thames Estuary when an unscheduled Coast Guard warning was broadcast
" Thunderstorms at North Foreland , reports of 30 knt wind "

Then followed mayday after mayday of small boats in panic, Ramsgate (N Foreland) was our nearest safe Haven, we didnt have the range to go back and the Coast Guard had run out of lifeboats.

Too rough to try to set a new chart course anyway.

We carried on as there was little choice and found darkened squalls with loads of spray/white tops but the waves weren't really any bigger as they hadn't had chance to build.


Last year again I was stuck off shore with no safe havens when the CG threatened Thunder storms with reports of 50 knt winds @@@@ , throttles eased forward but all we saw was lightening cracks, sea state was smooth.

Question

Do 50 knt squalls produce threatening waves ?
Can lightening hit the boat and what would happen ?







* These were both unscheduled weather warnings, I had not set off in them.

I am new to the South coast so they are new to me but I remember reading something years ago about a 'Spanish plumb' ?

 

[PowerYachtBlog]

I once had a terrible experience in Malta 3 years ago which finished in no damage
just a night awake kicking boats away who went off there anchor
in September (but not only) over here in central med it gets a bit dangerous as the lows get propelled by the heated sea which is at the period about 27 deg celcius

after that experience when I see a forecast for TS i usally sleep in a Marina

 

[mjf]

Yep, you have to watch out for these fellas.

Wind shifts around with large gusts , vis falls to almost zero in the rain and yes the sea state can alter fast too.


If none are forecast you are as you say a bit stuffed - keep an eye on the baro and watch the sky.

Last year i had just dropped the hook in Poole harbour and SWMBO reckoned rain was coming (clear blue sky - sunny and warm) felt it in her bones seemingly and asked me to put up all the covers.

Just finished the last zip and BANG - huge thunder and lightening show; switched on the radar and watched as nearby boats dragged and swung about all over the place.

It was the wind shifts that amazed me and the tropical force of the rain. I was going to wash down the boat when I was told to replace the covers in th event I got a shot blast - boat never cleaner!

 

[Bergman]

These things can be very nasty in a saily boat.

The wind actually falls vertically down out of the weather system and exert a much greater heeling moment on a yacht.

Once got hit by one on a Coastal Skipper course in the Solent. It put a heavy 34 ft boat on its side despite deep reefs.

Not funny at the time.

 

[mjf]

Dead right - I was ocean sailing once with a preventer on the mainsail, the wind shift was so rapid that we ended up with the mainsail backed. Not nice!

 

[Salty John]

1. A 50 knot squall will produce a confused sea, but usually doesn't have time to build any sort of consistent, large waves. The sudden loss of visibilty, horizontal rain or hail and the noise can be scary.
Not all TS's produce wind, but until they are nearly on you you don't know what to expect. I've sailed through them in dead calm, and I've been knocked flat by squalls.
2. Lightning is dangerous; I've had a direct hit, lost all electronics and had an on-board fire. You don't need a direct hit to damage electronics so it's always a good idea to unplug anything you can do without and put expensive items in the oven or a steel box. Crew should stay below and not touch metal.

 

[DAKA]

[ QUOTE ]

You don't need a direct hit to damage electronics

[/ QUOTE ]


I think the modern diesel engines would die if the electric fails.

when you turn the engine off the fuel is cut off instead of decompression therefore no electric power means no fuel .*

This is much worse than I thought.

* any one know if this assumption is correct ?

 

[andyball]

One of these then?

I'd say thunderstorms were a fairly common thing ( ok, ok, depends on weather ) in the summer down here. No thunder as I recall, but a June storm near lifted the northney "tent" up and away some years ago - err before they'd bolted it down at all.. one of the central supports fell over on the table we'd just been sitting at.

seemed quite a localised thing, since chimet/cambermet didn't really show it.; was aboard later & certainly the windiest I've ever heard/felt.

 

[DAKA]

Its a great idea Andy but I think it is likely to be used for a month and then would be left in cupboard along with the weather station, anemometer, sighting compass, Breathalyzer , ducky hook and all the other must buys you have forgotten where you stowed.

In any event if it detected thunder 75 miles away how do you know if it is on a collision course ?

 

[andyball]

a ducky hook?

I find that some food on the bathing platform gets them on board no probs.

 

[DAKA]

No one of those things on a pole that the sales man in the swindlers uses to pass a sheet through his display and back designed for catching a mooring buoy.


In real life of course the waves are moving the bow. the buoy is swinging and swmbo is more likely to wack you over the head the bl@@dy thing /forums/images/graemlins/laugh.gif

 

[Nat]

One in Ibiza last year resulted in seven or eight boats lost & many more damaged inc us. Wind went from dead calm to 50knts + in no time at all, Visability 0, torrential rain, hailstones the lot. An hour or so later nothing except a very confused sea & the aftermath.

 

[Andrew_Fanner]

Once upon a time it was said of the British Summer "three fine days and then a thunderstorm." Of course, we have yet to manage three fine days of late.

 

[nedmin]

Friends cruiser next to my berth was struck about 2yrs ago.Burnt out his wiring and damaged instruments,he was at home at time, fortunately I was away from my berth.altho. as steel I should have been OK, I think!!!