Engine off by key

M

muskie

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Newbie questions:

1. What happen if I used the key to turn off the engine (of course not success) and not cutting the fuel? Damage the alternator?

2. What is the proper motion/sequence for tacking/gybing? (I know how to do it under dingy but not sure about on keel bout)
i.e. ease genoa>sheet in main???>push tiller>move the body to other side>sheet in genoa>ease/adjust main

3. When do I need to bend(adjust the backstay) the mast?

4. Do I have to head to wind for reefing?

Thanks a lot!



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I will answer one, others can answer others...

3) As the wind gets up (especially when beating) is the simple answer. The effect of the backstay depends on your rig, whether it is a masthead (forestay to the top of the mast) or a fractional (forestay not to the top of the mast).

For a masthead rig, tensioning the backstay tensions the forestay. This reduces the sag to leeward of the forestay (and hence the foresail) which is a bad thing to have in anything more than light winds when beating. It hurts you pointing angle.

On a fractional rig the backstay has less effect on the forestay but more effect on mast shape and hence mainsail shape. When getting a bit overpressed when beating (ie angle of heel > 20 degrees, a lot of main trimming or luffing required) you can depower the main somewhat by tightening the backstay. This has 2 effects, it bends the top of the mast aft, and the middle of the mast forward. Consequently the top of the sail will now become more parallel to the wind, and will luff and flutter slightly. This is good, because it means that this part of the sail (which has the highest heeling moment) will not draw. Also lower down the middle of the sail will be tightened, flattening the sail and also reducing it's power. This technique of depowering is much more effective with a new unstretched mainsail. If it's old and baggy it has less effect.

The best way to see what effect it has on your sails is go and try it. Look for the effect on pointing angle, speed and heel angle.

<hr width=100% size=1>Adventures of the <A target="_blank" HREF=http://www.xrayted.fsnet.co.uk>Teddy Bear Boat</A>
 
I can answer a couple of questions

1) That depends on the alternator installation. Some systems are fitted with a device that collapses the field at the alternator, thereby protecting it if the circuit to battery is broken.

However, I'd probably say that the result of doing what you suggested, is likely fried diodes.

2) Tacking in a keel boat is pretty much as per a dinghy. Yoiu just need more room and don't have ti worry quite as much about shifting your weight around.

Remember tacking a boat with larger sail takes more time as the is more sheet to tighten etc etc.

3) Don't have an adjustable back stay.

4) depends on what sail you are trying to reef and how it is reefed. general answer in my experience is yes, as it makes things easierusually.

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1)Simplified: If it's your standard setup, when you turn of the engine with the key, you are actually als disengaging the alternator from the battery. The flywheel will still, however, keep turning the engine over for a few mor turns. Result: the alternator produces electricity, but can't get rid of it. Fried diodes will result. Same happens if you switch of the batteries or loosen the terminals with the engine running.
Buy Nigel Calder's Boat-owner's Mechanical and Electrical Manual for all this type of questions

2) Tacking: unless sailing a racy boat, cruisers have more momentum, and need a bit of help to get them through the tack.Ease off a bit to gather momentum. Sheet in the main hard, release the headsail, push on the tiller.
Avoid backing the headsail, as this causes massive amounts of chafe.
Turn a bit further than hard on the wind to pick up speed again, and then harden up slowly, while trimming the sails.

Gybing
Dangers: sheet snagging the steering pedestal or the helm. Blocks grabing clumps of hair. Bashed in skulls.
Gybes on bigger boats are less scary than on smaller boats: the momentum of the boom makes them slower but much more powerfull.
Sail downwind, sit on the opposite site of the helm (future windward site). The speed of your turn will determine the speed of the gybe. So controlling your heading is essential. The mainsail should follow the headsail. As theheadsail starts to sag, take in the main. Still no worries, you can sail perfectly downwind with the main sheeted in (good trick for light spinaker runs: reduces roll, and lets all the wind go to the spi).
Give the helm a shove and let the main out in a controlled sense. Otherwise the boom will go to fast, and together with a 20 kg mainsail, will have enough power to kick your rig overboard or break the gooseneck.

The thing about manouevres is preparing. It's always the same procedure
WARN: "ready to tack"
RESPONSE: "crew ready"
CHECK:make sure that everybody heard you, make sure that everybody sounds off. I'm not kidding here!
EXECUTE: "Tacking"

3) See above

4) No, better to sail/motor at a slight angle (slightly stalled). This will keep the boom away from the deck. On my boat, reefing is done at the mast base. A flogging boom at 6 bft can bash your head in.


<hr width=100% size=1>Group of people on the pontoon: skipper is the one with the toolbox.
http://sirocco31.tripod.com
 
1) based on my experience absolutely nothing. My ignition switch is handily placed for an inadvertent kick which is what must have happened last season motoring across Lyme Bay. Soemtime later, maybe minutes maybe hours, I casually glanced at the oil and temp guages. After the initial clutching sensation in chest and wallet at seeing them register zero I realised what had happend and with heart in mouth turned the switch back on. The instruments are back on and the alternator is charging all hunky dory. My (amateur) explanation for this is that the alternator only needs the ignition circuit for initial excitation current. Once it's producing and sensing its own the ignition circuit is superflous. And no, I am not confident enough in my theory to replicate the experiment for the amusement of the forum, but it worked for me.

Now if you turned off the main battery isolator, that could be a whole new tale.

The reason the engine did not stop is because unless you have a solenoid operated auto stop device (like a diesel car) a diesel engine will run until the fuel runs out or age gets the better of it, which is why I guess you have a seperate stop lever.

As for the sailing stuff try it and see. That's where the fun is but do remember to duck.

All the best,

Steve

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Gybing

I'd certainly centre the main before gybing, you really need to ensure that you are not sailing by the lee before centering or an uncontolled gybe will result.If you've got a traveller also ensure that's locked off as well or someone may get a very nasty surprise if its in the cockpit. If you are totally new to big boats it will be worth getting some form of instruction.

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frying tonight... (diodes)

there are some diesels which have no manual stop pull. with these, a cutout on the injector pump is held open by a solenoid which is released when you turn off the key, stopping the engine. all diesel cars are like this.

in your case there is no solenoid so turning the key doesn't cut out the fuel.

as to fried diodes, what causes the destruction is when the charging current is cut suddenly. without going into the physics, a sudden stopping of a current causes a massive voltage spike which destroys the diodes. it's the same principle as the contact breakers on a car which produce an instantaneous 5000 volt impulse.

when you accidentally turn off the key, it cuts off the tiny current to the instruments but- it does not cut off the much bigger current into the batteries so you don't wreck your alternator, you just get zero readings on your instruments.

wouldn't like to swear that every boat has this setup but my crew regularly turn off the key before pulling out the stop knob and i'm still on my original alternators. (mine are yanmars).



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Very impressive reply. But 'ease off a bit to gather momentum' might sound a bit confusing for a beginner. I'm not sure I can do any better. How about, 'come off the wind a bit to gather momentum'. The point is with cruisers you musn't pinch before you tack. BTW what happened to 'ready about, lee ho!'?

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I can only answer item 1

When you turn off the key in most installations, it is mearly the circuit that controls the red light that goes out when the alternator is charging. so if you think about it ,,, what happens in most cars, you turn the key off , the engine does not immediately stop dead. so do you see garages full of cars having new alternators every day, because they turned the engine off?


Others are confusing the connection between the alternator and battery, which usually fries the diodes, if removed while the engine is running.

<hr width=100% size=1>David
<A target="_blank" HREF=http://www.euroboating.net>http://www.euroboating.net</A>
 
You seem to have been given good answers to most of your questions.
If you detailed the type of craft more specific information could be on the effects of backstay tension and on the best tacking technique for your particular yacht.
Some boats are just like grown up dinghies and tack exactly the same. For example it is possible to roll tack an E-boat. On other boats it is very easy to get into irons when they are tacked incorrectly.

Reefing.

I presume you are asking about the main.

Some craft can heave to by fully backing the jib and puting the helm over. Then it is possible to reef fairly easily with the main in the shadow of the jib. This can sometimes be done single handed.

Alternatively just motor to windward and reef . If you are single handed you could steer with the tiller between your legs and you can reef if you have the lines led back.

Iain

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