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(@pippo)
Posts: 10
Lubber Registered
Topic starter
 

Is there a sort of equilibrium situazion, i.e. if all things are constant, then the boat proceeds with a constant speed and direction while flying a hull?


 
Posted : November 14, 2010 6:18 pm
F-18 5150
(@hobie18rich)
Posts: 1343
Member
 

I have found in constant wind and relatively flat water your still making adjustments. Sailing down wind like a snake. easy up, easy down, repeat as needed. Hull about 6 inches to a foot up .


 
Posted : November 14, 2010 6:41 pm
Baltic
(@6202)
Posts: 244
Mate Registered
 
Originally Posted by pinax
Note though that this thread has yielded two opposite answers for what to do with the spinnaker sheet when the windward hull starts to lift to much:

Originally Posted by Scarecrow
You should also experiment with the crew sheeting the kite on in gusts to flatten it and reduce power. Its counter intuitive but in some conditions works a treat.

Originally Posted by Brian P
easing the kite is also good at same time

A good skipper tells me that oversheeting the kite is a better way to settle the boat back down because he doesn't have to steer down so much. This struck me as backwards, but he would certainly know and I'll be trying it next time we're out. Can anyone explain to me why this works, or in what kind of conditions it works? I guess once you start to stall the kite you've got a lot less force sucking the mast over (and the boat on its ear)? Thanks.

So, two different schools here, somebody should start a poll.
Is my assumption correct, that the party

pro easing the spin

also votes for opening the traveller and vice versa?


 
Posted : November 15, 2010 5:36 am
(@alexvb)
Posts: 71
Member
 

Easing the mainsheet will not break the mast. Dropping it and letting it all run out all the way can make it break.

I pull the mainsheet in and out 1 arm length. Because it is one arm length, I never need to let got of it and risk it going all the way out.

I think that easing the main is the fastest method. It does three things:

1. It increases the twist int he main. This reduces the healing and pitching moment directly.

2. It creates more lee helm. This allows the boat to bear off without using as much rudder. This reduces the drag from the rudders and reduces the tendency of bearing away pushing the bows under the water because the rudders are the vertical when the boat flies a hull.

3. The top of the mast bends forwards because it is like easing a backstay. The way that F18 spinnakers are cut, this flattens the spinnaker and reduces its power.

I feel that easing the spinnaker or the traveler in a gust will increase the likelihood of pitch-poling. When the bows start to dig in the boat boat slows down and the apparent wind comes back. Easing the spinnaker or traveler will be powering up the main and spinnaker.


 
Posted : November 15, 2010 12:45 pm
(@azcat)
Posts: 424
Chief Registered
 

Great thread guys, keep it coming!

I am looking for the same Jeanie in a bottle. It seems that by the time I start to bear away, its to late. The spin gains so much power as the apparent wind moves forward that by the time I begin to bear away, its too late and I need to bear away hard deep sixing the bows.
Its fun and exhilarating but probably not the fastest method of getting down wind. It seems like there is something missing from the equation. I sail mostly on lake pleasant in Az where the winds are seldom steady so this may just be how I need to sail in these conditions, more time in the saddle will likely help. I will try running out an armful of main sheet next time out.

I sailed in Santa Barbara a few months back @ Wine & Roses, the winds were pretty steady 15mph and unidirectional. I watched as the F-18 guys blasted around the course seeming to stand their cats almost on their noses while under spin. I couldn't gain control of all that power on my N6.0. Hull flying wildly up and down, fighting to keep from diving the bows. At that time, My crew was very in experienced also but managed to stay on the boat. I was attempting to do my S turnes but couldnt make them remotely fast enough. Up the hull would go and by the time that I was able to attempt to turn down, the rudders were deep sixing the bows.
I have been told that I may need to be a little more patient while the boat gains speed without heading too close towards a reach. That makes sense and I am working on that whenever I go out. I just seems like the spin is stalling out, so I continue to turn up till I feel it power up, then attempt to turn down before the hull raises too far. Its usually too late and again, the rudders deep six the bows.
Should the crew be sheeting out more to get the spin to power up without me needing to turn up so far? It seems like the boat is tripping.


 
Posted : November 25, 2010 1:46 am
TEAMVMG
(@TEAMVMG)
Posts: 1188
Master Chief Registered
 

Same old question ....
How old is the kite and is it a decent design

If any boat needs a good kite with a controllable leech, it's the 6.0


 
Posted : November 25, 2010 6:27 am
(@alexvb)
Posts: 71
Member
 
Originally Posted by azcat
I sailed in Santa Barbara a few months back @ Wine & Roses, the winds were pretty steady 15mph and unidirectional.

I just missed you. I sail in SB almost every weekend of the year, but had to be out of town that weekend.

Originally Posted by azcat
Up the hull would go and by the time that I was able to attempt to turn down, the rudders were deep sixing the bows.
Originally Posted by azcat
Should the crew be sheeting out more to get the spin to power up without me needing to turn up so far?

You need to keep the boat moving fast and you need to head up and down in phase with the wind. I suspect you were out of phase. You need to be sailing deep, not heading down, when the gust hits and sailing high, not heading up, when the lull hits. Its all about anticipation. Get your head out of the boat looking at the wind.

Something that is likely unique about ocean to you are the long period waves. Frequently in SB the waves play a larger part in powering up and down the boat than the wind. Because the waves are fairly periodic, it is easy to anticipate what will happen next. Again, you need to have your head out of the boat looking at the waves / wind.

Second, you need to not slow down. Because the center of gravity is above the water, the act of turning toward the direction that the boat is healed will level it off. This is the same effect that keeps a bicycle balanced. Going twice as fast make the effect four times larger because the force goes up with the square of speed.

Don't head down too hard. The rudders will create drag and it won't be as fast of an angle. Keep the spinnaker trimmed. You are correct, your crew should let out the spinnaker any time the hull comes down. It might be frustrating at first because the boat will accelerate, the apparent wind will come forward and the spinnaker will try to collapse. Again, the crew has to anticipate this. When the crew feels the boat accelerate, they need to be ready to sheet back in.


 
Posted : November 26, 2010 1:12 am
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