DN Sailing Kinetics

[DN 5449]

Watching Sherry's Vedios ,he talks about squeezing forward in the boat,other times I have heard about sailors moving back.I have sailed the Laser a lot and have a pretty good understanding of the kinetecs involved with making it go fast.I am some what in the dark as to how, where, and when to move my body when sailing the DN to max. my performance.

[DN5358]

....I am some what in the dark as to how, where, and when to move my body when sailing the DN to max. my performance.

 
Mike I am similarly in the dark.  I focused on getting into the boat this year and being comfortable with the feet on/near the forward bulk head.  Unfortunately the experimentations I had with weight placement had mixed results.

Someone please help!

David

[Paul Goodwin - US 46]

Here is my quick summary (YMMV)

Assuming you have enough wind speed to reach top gear - this is not a light wind drifting techinique...

1) To allow maximum acceleration from low speed, foot off and move back in the boat (and out slightly to windward if necessary) to increase righting moment.  As boat speed builds, continue pulling in the mainsheet and steering the boat to maintain a light weather runner, until almost "two-blocked".  Do this off the starting line and after tacks in order to reach top speed.  This also allows for maximum "hair on fire" speed if you have overstood, but watch out for overbending the mast in this mode!

2) As acceleration tapers off and you approach top speed, move forward in the boat, sheet in to the max, and feather upwind.  Streamline your body as much as possible.  Get under the boom, tuck into the cockpit and cut down wind drag.  If you are set up properly to pull back on the boom this will derotate the mast and allow for higher speed and greater pointing - the much desired "ward speed" effect.

Refinement of this technique can take years, and will absolutely be required to move up to the highest levels of DN  racing.

Paul Goodwin

[DN 5449]

Thanks Paul,what does moving forward do besides make you more streamlined?Also what about when you overstand the weather mark and are footing in, or rounding the weather mark and flying a runner do you still stay low and forward or is this a good time to move back and out?

[Paul Goodwin - US 46]

There are a number of related effects that all have to come together.  Here is my take, again YMMV - I am sure there are lots of people that would disageree with my analysis...

While you are accelerating from a low speed, you need to maximize power.  You do this by:
a) Foot off to increase the apparent wind angle
b) Sheet out slightly to gain a sail angle advantage for forward drive
c) Don't pull back on the boom, which lets the mast rotate, to increase draft and open the leech
d) Slide back in the cockpit to increase righting moment and counteract the increased power

As you increase your speed, the apparent wind angle reduces and you need to sheet in to maintain sail power.  This reduces forward drive, and at the same time air resistance increases rapidly, so acceleration drops off.  At the same time as sheeting in, you should be rounding up slowly.  You will reach the point where you are fully sheeted in, but not "two-blocked" - the blocks have just come together, but the boom blocks are still above the deck blocks.  You will be pointing pretty high and going fast.  If you find at this point you are pointing high and going slower than your competition, you screwed up!  This means you turned up wind before reaching your top speed potential.

Now you need to make changes to reduce air drag.  If you do nothing else except reduce air drag you can point higher - you will have less sail power, but the lower drag allows you to maintain speed at a higher angle.  Here is how this is accomplished:
a) Slide forward in the cockpit and tuck in.  This reduces air drag, and distributes your weight more equally over the runners.  This also allows the boat to hike more freely so you can feel your sailing angle at the lower power level.
b) Sheet in hard to go "two-blocked".  If you are properly set up, this will cause the boom blocks to roll backward over the deck blocks, pulling back on the boom.  This derotates the mast, reducing the draft, and at the same time it tightens the leech to reduce twist.

When you make the changes outlined above, the boat will hike and you can round up maybe 5 degrees without loss of speed.  "Scotty - give me Warp Factor Five!".  This is the much talked about DN "Warp Speed".  I don't know of any other boat that displays the effect like the DN.

Once you are in this mode, the mast will be bending very freely.  If you have overstood and need to foot off, watch the mast carefully.   You may need to sheet out a little to control mast bend.  Also when you round the weather mark, watch that mast!  If you foot off and sheet out, power will increase very rapidly, this is a condition where you will need to slide back in the cockpit, maybe even lean out a little, to control the power and keep hiking in check.

Sometimes you can manage a weather mark rounding by only sheeting out a little, and staying forward in the cockpit.  In this move you maintain control by using the centrifugal force in the turn to keep hiking in balance.

[DN 5449]

That is fantastic thanks again.I think I am guilty of pointing too high too soon.looking forward to trying this out ,hopefully tonight. This idea of watching the mast is very forun to me.

[DN5358]

Thanks Paul!
Let see if can remember and implement this next year.

David

[Geoff Sobering]

Ron Sherry has collected a series of his Runner Tracks articles into one document at: http://iceboatracing.com/Become%20A%20Faster%20DN%20Sailor.pdf

Two of the articles are particularly germane to this discussion: "The Racing Tack" and "Five Steps to a Great Start".

[Paul Goodwin - US 46]

Of course, when I say "watch the mast", I don't mean "stare at the mast and run into things".

The race course and other boat are all around you and need constant attention.  You will become accustomed to knowing what the mast bend is doing, just by the visual curvature and motion picked up casually, even by peripheral vision.  An especially important indicator is the "distance" between the mast and forestay, caused by the mast bend relative to the straight line of the forestay.

We are all guilty of pointing too high too soon, even the very top sailors had to learn how to avoid this condition.  You can also be forced high early by the boats below you.  The most important part of starting may be to get out in front of the boats below you so you don't get forced up.  It is very cool to get a good start, then foot off across the bows of a string of boats that are pinching, knowing you will never see them again...

The very top of Gold fleet does not usually have this problem, because they all know the pitfalls of pinching off the line.

[us5285]

      Thanks Paul for the great article. I've been sailing DN's for almost ten years now and have heard many of the steps you outlined diring that time. Untill now I have never understood how to put them together and a big thanks to you for making it understandable. (yeah ten years)
       I'm positive I have been leaving out at least a couple of the steps and know I have often been one of the sailors pointing too high too soon.
       I realize its work but if you get a chance; outlining the steps for building speed down wind and after a jibe would be awsome.
       Thanks again!
 
       Chris US5285