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Survival tactics.. #205739
03/15/10 09:41 PM
03/15/10 09:41 PM
Joined: Jun 2001
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South Florida & the Keys
arbo06 Offline OP
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OK. Down wind in heavy+ winds, can you sheet tight and travel in to reduce attack angle?


Eric Arbogast
ARC 2101
Miami Yacht Club
-- Have You Seen This? --
Re: Survival tactics.. [Re: arbo06] #205740
03/15/10 10:10 PM
03/15/10 10:10 PM
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Northfield Mn
Karl_Brogger Offline
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Yep.

Re: Survival tactics.. [Re: arbo06] #205768
03/16/10 07:13 AM
03/16/10 07:13 AM
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Jake Offline
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yes - but watch for a chinese gybe that will overpower the rudders in a split second. With wind come shifts.


Jake Kohl
Re: Survival tactics.. [Re: Jake] #205804
03/16/10 11:47 AM
03/16/10 11:47 AM
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And you want to be as close to DDW without risking the unintentional gybes as Jake mentioned.

So, how do you get there? Do you sheet/travel in first, then turn down, or turn down then try to sheet/travel in, or do you sheet first, head down then travel in, or something else altogether?

Personally, I've never even tried this, but there have been times when I wished that I had.

Obviously, this is all assuming sloop or uni with no chute...

Mike

Re: Survival tactics.. [Re: arbo06] #205806
03/16/10 12:19 PM
03/16/10 12:19 PM
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Hamburg
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Originally Posted by arbo06
OK. Down wind in heavy+ winds, can you sheet tight and travel in to reduce attack angle?

If it is really heavy plus survival, you may come to a ddw course where you can sheet in, but you will never come out of it. Don't ask why I know...
The survival mode is head in the wind, take boards and rudders up, sit on the bow (hold tight) and sheet in. YOu can any time go back and sail upwind. Works also in surf.

Cheers,

Klaus

Re: Survival tactics.. [Re: brucat] #205807
03/16/10 12:26 PM
03/16/10 12:26 PM
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Hamburg
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Originally Posted by brucat
And you want to be as close to DDW without risking the unintentional gybes as Jake mentioned.

So, how do you get there? Do you sheet/travel in first, then turn down, or turn down then try to sheet/travel in, or do you sheet first, head down then travel in, or something else altogether?

Personally, I've never even tried this, but there have been times when I wished that I had.

Obviously, this is all assuming sloop or uni with no chute...

Mike


Go upwind, releae the sheet, but not the traveller and turn quickly the sterns into the wind. Sheet quickly in. The crew can take the boards up, if she/he dares to go forward. Be careful on the tiller, the leech is now the luff, like Laser sailing. As I said, the problem is changing the course again. In opposition to a Laser or windsurfer, your sail swings only to the shrouds.

Re: Survival tactics.. [Re: Smiths_Cat] #205813
03/16/10 02:02 PM
03/16/10 02:02 PM
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France
pepin Offline
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Survival? I all depends on the circumstances. One of the possible option in survival conditions is to turtle the boat on purpose, it is far more stable pointy end down. It's also going to slow it drifting giving you more time to think and/or call for help.

Or go head to wind and get the main down. Roll it tight, and attach it solidly. If it it windy you'd be surprised how well you can point or the speed you can reach DDW with just the mast!

Re: Survival tactics.. [Re: pepin] #205825
03/16/10 03:25 PM
03/16/10 03:25 PM
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So this is a Chinese gybe? Yip!

grin The equipment-related chinese gype at about 2 minutes.

Actually, that probably isn't gybe. The bow looks to be knocked around by a big wave and a hard tack was the result. Chinese tack?

Last edited by JJ_; 03/16/10 05:19 PM.
Re: Survival tactics.. [Re: JJ_] #205833
03/16/10 04:25 PM
03/16/10 04:25 PM
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brucat Offline
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That, as they say, is NOT fast...

The real stunner for me was the guy saying (repeatedly, even) "Get me a knife." Why everyone doesn't have one attached to themselves at all times on something like this amazes me.

Mike

Re: Survival tactics.. [Re: brucat] #205843
03/16/10 07:13 PM
03/16/10 07:13 PM
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Michigan
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no joke. why wouldn't they have knives

Re: Survival tactics.. [Re: PTP] #205853
03/16/10 09:01 PM
03/16/10 09:01 PM
Joined: Jun 2001
Posts: 1,911
South Florida & the Keys
arbo06 Offline OP
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Are Russians allowed to carry knives?

I was waiting to see the main come flying across, that is what I would be afraid of.

The reason for the post is... I once sailed from Miami to Key Largo and the wind unexpectedly built to about 30+ from the North as we were more than half way down the bay heading south.
We were traveled out so far that the battens were bending to fore against the shrouds. At that point we were "pointing the boat" not sailing it.


Eric Arbogast
ARC 2101
Miami Yacht Club
Re: Survival tactics.. [Re: arbo06] #205858
03/16/10 09:41 PM
03/16/10 09:41 PM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
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I think it was the '05 steeplechase that started out that way. It took us three attempts to bear away coming out of Angelfish Creek...once we did make the turn, there wasn't much sense of relief as we were not very much in control dead downwind with main and jib.


Jake Kohl
Re: Survival tactics.. [Re: Jake] #205868
03/17/10 12:39 AM
03/17/10 12:39 AM
Joined: Dec 2004
Posts: 140
Brisbane Queensland- Australia
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So how many people have installed reefing points on the mainsail to depower the rig and give you speed rather than abundant heeling force. Most monos can do it quickly and easily on and off the wind, why are reefing points not standard on cat main sails?

Re: Survival tactics.. [Re: Qb2] #205899
03/17/10 09:17 AM
03/17/10 09:17 AM
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League City, TX
flumpmaster Offline
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Originally Posted by Qb2
So how many people have installed reefing points on the mainsail to depower the rig and give you speed rather than abundant heeling force. Most monos can do it quickly and easily on and off the wind, why are reefing points not standard on cat main sails?


To depower a sail you can make it smaller (reef), or flatten it. Modern high performance beachcats focus on flattening it - by application of high main sheet and cunningham tension. In addition, the top of the mast will tend to bend off to leeward which 'spills' pressure when the apparent wind is forward. The combined main sheet and cunnigham tension place a reasonably large load on the head of the sail. This is why most beachcat main sails latch to the top of the mast - as that is a robust anchor to resist those forces rather than it all being on the halyard.

Older designs with lower sheet / cunningham tension (such as the Hobie 16) did have the ability to reef the main. In those cases, the main halyard is loaded and typically has a wire section with a slug that is trapped in a V on the front of the mast. A couple of slugs are placed on the wire section for the full and reefed sail positions.

When I have seen those older designs reefed the mains do not look very flat to me - which means they still develop a lot of power reaching or going upwind. In a 'survival' mode sailing downwind the reduction in sail area would probably be useful. It seems to me that the window where a reefed main would provide advantage is narrow. Above a certain point you'd better turtle the boat or take down the sails (difficult in big wind/wave state).

Hobie Tiger mains have been supplied with small reef point grommits - but not reinforced at those locations. I think they were included to comply with a class rule rather than for real world use. Smythe put reef points on one 18HT sail I've seen - but I never saw it sailed with the reef in.

Chris.


Dave Ingram is my president. tcdyc rules
Re: Survival tactics.. [Re: flumpmaster] #205911
03/17/10 10:26 AM
03/17/10 10:26 AM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
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Originally Posted by flumpmaster


To depower a sail you can make it smaller (reef), or flatten it. Modern high performance beachcats focus on flattening it - by application of high main sheet and cunningham tension. In addition, the top of the mast will tend to bend off to leeward which 'spills' pressure when the apparent wind is forward. The combined main sheet and cunnigham tension place a reasonably large load on the head of the sail. This is why most beachcat main sails latch to the top of the mast - as that is a robust anchor to resist those forces rather than it all being on the halyard.


In addition to providing a solid anchor point with the hook at the top of the mast, it also reduces compression on the mast by 50% over having a halyard carry the sail loads back down to the foot of the mast (again).


Jake Kohl
Re: Survival tactics.. [Re: Jake] #205915
03/17/10 11:18 AM
03/17/10 11:18 AM
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brucat Offline
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Originally Posted by flumpmaster
Older designs with lower sheet / cunningham tension (such as the Hobie 16) did have the ability to reef the main. In those cases, the main halyard is loaded and typically has a wire section with a slug that is trapped in a V on the front of the mast. A couple of slugs are placed on the wire section for the full and reefed sail positions.


…” the main halyard is loaded”…

Not on the H16s from the early 80s. Like you said, the slugs in the halyard clipped into the fitting atop the front of the mast just like the current design. So, the only part of the halyard that had any load was from the shackle to this fitting. Not sure about older (70s) models.

The main reasons that I’ve heard for Hobie discontinuing the reef setup was the introduction of the Comptip (and requirement for the metal part of the halyard to not come down to where people could come in contact), and the market feedback that no one really used it. Matt Miller might have more info if he’s reading this.

Originally Posted by Jake
In addition to providing a solid anchor point with the hook at the top of the mast, it also reduces compression on the mast by 50% over having a halyard carry the sail loads back down to the foot of the mast (again).


I’m trying to wrap my head around this concept, but it’s not working for me. The load with the main attached to the top of the mast is the same as if it’s brought back down to the bottom. If you take away the purchase, you don’t take away half of the load, all of it transfers to the bolt rope, which extends the length of the mast.

In other words, you reduce the load on the bolt rope by fastening the hayard at the bottom of the mast, but the load on the mast is the same either way. What am I missing here?

Mike

Re: Survival tactics.. [Re: brucat] #205927
03/17/10 12:41 PM
03/17/10 12:41 PM
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mikekrantz Offline
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Nope the compression load is 2:1 on the top the mast if the halyard is cleated at the base. It's 1:1 if it utilizes a halyard hook.

Re: Survival tactics.. [Re: mikekrantz] #205931
03/17/10 01:04 PM
03/17/10 01:04 PM
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brucat Offline
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OK, so you're repeating Jake. Can either of you explain? Especially since it loops over the top of the mast (H16 doesn't hook behind the mast like other cats).

I'm feeling so confused... :-0

Mike

Re: Survival tactics.. [Re: brucat] #205933
03/17/10 01:34 PM
03/17/10 01:34 PM
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France
pepin Offline
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If the hooked sail is pulled down via the downhaul the mast is going to present a nice curve, flattening the sail. If you have a halyard created at the bottom of the mast instead when you pull the downhaul the result will not be the same as the pressure on the front of the mast, where the descending halyard line is, will be getting on the way of the mast bending. Routing the halyard inside the mast track doesn't solve the issue either as now the under tension descending halyard need to follow the bend of the mast which is it going to do only by pressing on the sail rope. That's one reason we use hooks.

Now the second reason is compression. When you have a hook and pull on the downhaul the tension applies only on one side of the mast. If your halyard is cleated at the bottom of the mast the pressure applies up *and* down the mast, doubling the amount of compression the mast has to sustain for the same downhaul amount.

And a third reason is drag. Having the halyard hidden in the mast track reduce drag, and you can't put an under tension halyard inside the track.

Re: Survival tactics.. [Re: brucat] #205934
03/17/10 01:44 PM
03/17/10 01:44 PM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
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Originally Posted by brucat
OK, so you're repeating Jake. Can either of you explain? Especially since it loops over the top of the mast (H16 doesn't hook behind the mast like other cats).

I'm feeling so confused... :-0

Mike


If the sail is hooked at the top of the mast and you pull down with 100 lbs of force, you have 100 lbs of tension on the mainsail luff and 100 lbs of compression that the mast has to resist.

If you have a halyard that turns around a sheave at the top of the mast and is cleated at the bottom (i.e., the halyard cleat at the bottom of the mast is what keeps the sail from falling down) and you apply the same 100lbs to the tack of the mainsail, you have 100 lbs of tension on the mainsail luff and 100 lbs of tension on the halyard. You now have two 100lb tensions that the mast has to resist equaling 200 lbs of compression on the mast.


Jake Kohl
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