Its Electrifying
Vega
Hugh and Annie
Fri 14 Oct 2016 21:46
So, what to do? When gybing (changing tack but with the wind coming around the back of the boat) it is good practice to sheet in the mainsail as close as possible to the centreline of the boat as you go around so that the boom has only a short distance to be whipped across the boat at the point of the gybe, greatly reducing the chances of any damage or even breaking the boom. You are able to do this as the boat turns as there is less pressure on the mainsail as the rear edge faces more into the wind. Would this pressure reduction be enough to pull down the front of the sail? Answers on a post card please……………
In our case the answer was no. We could reef the back of the sail but the front remained an ugly bag pinned to the mast and lazyjacks by the top full length batten. The arrangement gybed easily and we did lose speed with the boom kept on the centreline. Good job it was still dark when we arrived in the shelter of Santa Marta and we could get the mainsail down properly before anyone saw us.
Lessons learned? If a strong wind is at all likely put a third reef in the mainsail beforehand. For us this would be the equivalent of a storm tri-sail which seems drastic but it is remarkable how little sail is required downwind in a blow to maintain speed. Rig a line from the third reefing point down to the front of the boom so that the front of the mainsail can be winched down (there is a winch on the mast) if required. Alternatively drop the mainsail altogether and run downwind under the genoa alone. Any other suggestions out there?
With thunderstorms, a daily occurrence here, we have thought much about how to deal with a lightning strike. I happen to be leaning on the mast support writing this as a big storm approaches so you can imagine we haven’t come up with many constructive actions yet. We did put phones and laptops in the oven one evening. Internet research suggests that a lightning conductor fixed to the top of the mast and a wire from the bottom of the mast attached to a one foot square copper plate suspended in the water should earth any strike away from the boat. One suggestion from a fellow cruiser is to wrap a chain around the mast with one end dangling into the water. Seems more practicable than the wire and copper plate but I notice he hasn’t done this (although he does have an aluminium boat that perhaps is already earthed by virtue of being a floating conductor). Another thought, carefully debated with Annie, was whether it is better to be connected to a marina power supply with its earth when struck by lightning or not. We decided it might be better to be connected but on following this up with more internet research on marina electrical supplies (albeit concerned primarily with effects upon galvanic currents and corrosion) it seems the whole subject is both complicated and little understood (at least by the likes of me reading this stuff).
Moving on from lightning strikes to corrosion, one fellow cruiser extolled to me the virtues of the zinc anode he had suspended on a wire in the water when in a marina with the inboard end of the wire clipped to his guardrail. He said that this stopped the rapid corrosion of his boat’s fixed anodes when connected to a marina electrical supply. I took this at face value at the time but my internet research on the subject suggests that such an anode is probably a waste of time unless connected to the engine block or prop shaft where most corrosion occurs. It would be most useful with a steel or aluminium boat where the whole thing is likely to corrode in preference to plastic boats if all are connected to the marina supply. Even I, when I thought about it, could see that attaching an anode to your guardrail isn’t going to do much for your propellor unless the guardrail and propellor are connected electrically. Which reminded me of an article I had read some while ago about whether metal through hull fixings should all be wired together. Ours aren’t. Some maintain categorically that they must be wired together while others maintain that there is nothing to be gained from this. For something so significant you would think there would be a definitive answer. The cruiser with whom I had discussed lightning strikes has an aluminium boat and only connects to a mains electricity supply for the shortest possible period in order to charge his batteries, his boat being a large floating anode that will corrode preferentially when connected to the same electrical connection as plastic boats. So I was intrigued when he asked if our boat is electrically bonded i.e. all the metal parts are wired together. If some boats are electrically bonded then I can now see why an anode attached to the guard rail would be a good source of corrosion protection. On the other hand if boats have anodes fixed to the corrosion prone parts what is the advantage of joining all the metal parts together with an electrical connection? I can see the reason for joining all the underwater metal parts together electrically and into an anode but why do this if they each have a separate anode? How vulnerable are our bronze through hull fittings without being wired to an anode? Answers please in an email as a) I am genuinely interested and b) I am sure there are one or two of my small group of readers who will have an answer……………………
Still on the subject of electricity we now have first hand experience of the consequences of a metal pontoon being a live conductor of a 120 volt mains connection. A story that would both thrill and shock the Health and Safety Executive and legions of health and safety managers in the UK (pun intended). Sadly I have run out of room to recount the experience here but Annie or I will do so in a later posting.