Death Roll

by Rob Sykes (AUS)

Many thanks to Rob for his contribution in a comment that deserves to be a post.

A bit off topic, but helping sailors. I promised I would send this data to Doug (not sure if Pam was present at the time). I have just returned from Hyeres and was reminded of my promise by a photo on Thom Touw showing a master death rolling and doing it incorrectly.

Neither of these film clips were posed or acted.

http://youtu.be/nCKovYELmC8 

http://youtu.be/eXTLezMkgLU 

Death roll

This is about 12 knots, Note position of rudder (central) and how Mitch is holding the main sheet. Nice and fast.

Mitch starts an up turn to get speed to catch a wave. You see him sheet in and accelerate. Almost immediately he bears away to take advantage and jump to the next wave. He dumps the sheet but does not bear away enough so the boat begins a death roll.

He moves to lee trying to bring the boat upright, but sheets out (now the boat wants to bear away more) instead of sheeting in. He also pulls the rudder so as to luff up. This action tips the hull over to windward even more and he goes in.

He might well have saved the capsize by sheeting in instead of out during the death roll and also bearing away violently.  Saving a death roll. Running, rudder central (good) but the main sheet from the block. This is not as fast as Mitch. (He is very very much faster than me, particularly downwind).

Here the scenario of an up turn followed fast by a down turn is the same. The wind was a bit heavier (15 knots). I was under sheeted anyway as the stopper knot on the main sheet made the boom go out too far.

The up turn is ok, you see the boat accelerate. Immediately I dump sheet to do the down turn, but because the stopper knot is in the wrong place, the boom goes too far and the boat starts to go over to windward. Because I have the main sheet from the block, as I move to leeward, I tighten the main sheet (good) and note how the helm is in bear away mode, not luff up. The boat is not responding so I push the rudder hard and the boat comes upright. If I had pulled the rudder, I would have gone in. See how the water flows into the cockpit.

Summary

Think of the boat half over to windward. The rudder blade is only just in the water. If you pull the rudder, lift the transom up and twist the boat and increase the tipping motion of the death roll. If you push the rudder, you sink the transom and twist the boat decreasing the tipping motion of the death roll.

You may have to play the movie at super slow or single frame to see the sheeting and rudder positions.

Thanks to Steve Cockerill for showing me how to do it.

Gybing - Thoughts from Steve Cockerill, Frank Bethwaite... and me

By Doug

In the post about Laser Mainsheet Snags, comments were made about how Steve Cockerill's video suggests letting the boom out to initiate a heavy-air-gybe. I commented that surely letting the boom out would not work because it would be too unstable.

The boom is waaaaay too far out. But even a little out makes things unstable.

Then one of the sailors that Steve sponsors said this comment was correct and the reason for letting this boom out was to intentionally make the boat unstable.

So, let's recap:

• We're in strong wind on starboard and want to gybe.
• Almost all top-level events are held in open water, so there are probably big waves - a tricky situation.
• Steve suggests letting the boom out which is how you invite a death roll and swim (the twist at top of the sail is pushing everything to windward).
• The center of effort is now to the right of the boat which now wants to bear off.
• This initiates heavy air gybe with little or no rudder movement.

I have never tried or even seen this, but it's brilliant!! Except for one problem - it's a controlled heavy-air-death-roll-that-ends-up-in-a-gybe. Steve is a better man than me because my priority for a heavy-air-big-wave-gybe is getting the boom across without tipping.

This brings to mind comments from another world-class sailor. Several years ago, there was a Sailing World cover story article by Frank Bethwaite about how you bear off in a strong gust rather than the more intuitive heading up. 

Trying to head up in a strong gust.

Frank called this 'steering for balance' and it was controversial at the time, with lots of people saying that Frank was wrong. Frank was, of course, correct.

One of the key points Frank made was that by turning sharply in a gust, the boat wants to 'trip' over the centerboard. And the higher the speed, the more the importance as you lose control from the pressure in the rig.

I learned this by accident about ten years ago practicing on a local lake in a 30 knot breeze. With each gybe, the boom would slam across and there was a huge pressure on the rig and in the steering as I tried to get the right balance again. We've all had this problem.

So I tried something different and for me, counterintuitive: as the boom slammed across and I was on a new tack, I bore off to head straight downwind - steering for balance. The helm went neutral and everything worked beautifully, even in 30 knots.

So here's a combination to try when it's really honking - sheet out a little to start a gybe, let the boat bear off on its own, and as the boom slams across, bear off sharply to neutralize the helm. Oh and Ute, try to not wrap your mainsheet around the end of your boom!

In the 90s, the Worlds courses included a gybe mark and in a breeze it was referred to as the graveyard because so many boats would tip at the mark.  My practice sessions would include gybing at a certain point in a breeze and not waiting for lulls.  The goal was to have enough practice and confidence to gybe at any time while maintaining control at all times so that I could maneuver around boats that were scattered in the graveyard. That era inspired Laser sailors to practice and perfect various techniques.  That's the key ... pick a technique that works best for you and then practice it until you're comfortable.

Laser Mainsheet Snags

By Doug

This good question comes from one of our German readers: When gybing in medium or stronger winds, I often encounter the problem that the main gets caught around the end of the boom. In regattas it is one of the many reasons for frustration.

There are 3 ways for a Laser main to get caught:

1. The main gets caught around the transom when jibing. This happens to all of us. In light air, I like to pull the main in as much as possible in front of the ratchet block so there is less slack to get caught, and the boom goes out much easier without having to run through the ratchet. When the wind is higher, a sharp tug when the boom starts to come across usually lifts the mainsheet just enough to clear the transom. If it gets caught, the way the pros free it is by hitting the inside of the main with the tiller extension rather than moving to the back to free it by hand.
2. As mentioned, the main gets caught around the end of the boom. I've had this occasionally happen and am not sure how to prevent it, so I'm open to suggestions. But one thing is for sure - the only way to fix this is by reaching back and freeing it with one hand. This can be tricky in a breeze.
3. The main gets caught in the clue boom block. In my 38 years of sailing Lasers, this has only happened to me once and yes, it was at a critical moment in the final race at the Jeju Worlds. Pulling harder only jammed it more, so my best advice when you cannot figure out what's wrong is to stop, go back, and look at the problem. In my case, pulling hard just made things much worse.

Peckover's Law: easy problems happen during easy times. The really difficult problems nail you at the worst possible times.

Update 5/28/14:  I'm putting this back up to the top because we're still getting comments and it appears there is more to discuss.