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Winter series session 4: To tack, or not to tack? That is the question

A bit of a lighter turnout last night as we focused on the critical question of when to tack.  There’s a heck of a lot of material in Walker’s book on the topic, and some of it is still a bit cryptic, so we focused on two particular areas: i) a game plan for the windward leg, and ii) what to do when someone else tries to trap us in their backwinded air: the dreaded lee bow.

Game Plan for the Windward Leg

During the windward leg, we have different considerations at different times.  For simplicity, I’ll divide it into four segments.  On a typical first upwind leg (about 20 minutes), each segment will be about 5 minutes long.  We begin this ‘game plan’ just after the start.

  1. Segment ONE: Climb the ladder rungs.
    • Treat changes in wind direction as oscillations, but be vigilant about evidence of the beginning of a progressive persistent wind shift
    • Emphasize short-term gain over long-term position on the course
    • Get onto the lifted tack as soon as possible, so that we are in phase with the oscillations for the leg
    • Seek out clear air, but don’t make an impulsive decision (see next section)
    • The next tack should be to consolidate a gain.  For example:
      • Tack on a header to sail the next lift — this will gain us ladder rungs and send us back toward the rhumb line and decrease our leverage
      • Tack before the next lift — this will reduce our leverage, which is important as we transition to the second segment
  2. Segment TWO: Position ourselves strategically.
    • Sail in clear air
    • Stay in phase with the oscillations as much as possible, while also…
    • Sail to the advantageous side of the course to take advantage of
      • More wind
      • Expected progressive persistent shift, if it materializes
    • Don’t get carried away with our theory — it might be wrong!
      • Tack back toward the rhumb line, especially if most of the fleet is on the opposite side of the course
  3. Segment THREE: Benefit from the strategic choices
    • Sail in clear air
    • Stay in phase with the oscillations as much as possible, while also…
    • Take advantage of any progressive persistent shift that is in progress
    • Avoid painting the corners
  4. Segment FOUR: Approach the layline
    • Sail in clear air
    • Cover the competitors behind us to consolidate that gain — don’t sacrifice this by chasing the boats ahead of us.
    • Anticipate the next oscillation — which will be the last one of the leg — and plan the approach to the weather mark
      • This may mean treating the next oscillation like a progressive persistent shift, in which case we should sail on the headed tack for a while before it starts.
    • Join the “starboard tack parade” on the layline only about 100m from the mark
      • This parade is full of bad air and there are no passing opportunities
      • This means we will have to get good at hoisting the spinnaker with very little prep time — maybe by setting the pole after the hoist

Responding to the Lee Bow

There is a distinct disadvantage to having a competitor just off our lee bow: we are wallowing in the backwinded air they create.  The impact is that we will sail slower and point lower than the boat ahead.  This is particularly bad when the boat ahead is a slower boat, since we won’t be able to sail any faster than them — we’ll be slower than our competitors.  Interestingly, there is a distinct advantage to being the boat ahead in this situation — that boat gets a lift relative to the entire fleet.  So there are two incentives for other boats to try to trap us in the lee bow position.  Of course, we have the same incentive to do this to others.

The circumstance arises in four situations on the race course:

  1. Just after the start: only the most leeward boat is in clear air.
  2. When we catch up to slower boats on the same tack as us
  3. A competitor attempts to tack onto our lee bow
  4. On the layline: “the starboard tack parade”

It’s best to avoid the situation completely, for example by avoiding the starboard tack parade on the layline, and by choosing when to tack so as to avoid catching up to slower boats on the same line.  We’ll also learn some starting strategies that avoid (or at least reduce) the chance of a lee bow situation.

When it can’t be avoided, it can always be anticipated.  We will be able to see the situation developing and have a chance to decide ahead of time whether we want to tack or keep heading in the same direction.  Specifically, we have four options:

  1. Roll over the competitor
    • When will it work: the competitor will finish their tack less than half a boat length ahead of us, and more than half a boat width to leeward
    • How to do it:
      • luff as soon as they start their tack
      • shift gears to Pointing Gear
      • once abeam and about a boat width to windward, settle back to Go-Gear
  2. Foot below the competitor
    • When will it work: Only try this when the competitor will finish their tack clear ahead, and only slightly to leeward of us AND one of the following is true:
      • we are on a strongly lifted tack (the next header will put them in our lee bow!)
      • we are able to accelerate faster than our competitor (planing boat in high wind/waves)
    • How to do it:
      • A soon as we will be able to clear their stern, shift to Starting/Footing Gear and swoop down tight to leeward
  3. Stay the course
    • When the competitor executes a really good Lee Bow maneuver, we won’t be able to roll over them or foot below them.  We have to decide whether to tack or not.
    • If staying on the current tack is consistent with our game plan, we should calm down, take a deep breath, look around, and plan thoughtfully when we want to escape from the lee bow.
    • We will lose about 4 boat lengths (assuming the boat ahead is as fast as we are), but this may be less than the cost of 2 tacks (which will cost somewhere between 2-4 boat-lengths each)
    • When we do tack away, we should do it because it will benefit us tactically.
  4. Tack
    • If our game plan would have us tacking away soon anyway, then we should avoid the lee bow situation by tacking before we lose speed.

The key is to be ready.  We’ll see the situation developing ahead of time, and decide ahead of time whether we should respond by tacking.  If not, then we need to be ready to shift gears as needed to either roll over them (pointing gear), or foot below them (starting/footing gear).


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