Skip to main content

Trim to the verge of stall: North U Sail Trim Course

“Trim to the verge of stall” was our instructors answer for nearly every question.  And the reason always seemed to be because that would keep the keel working for us underwater.

Connecting those dots was sometimes clear and sometimes well over our heads, but we each took away some gems from our day at Lakeshore Yacht Club in Etobicoke.  Representing PERSPECTIVE were Kiwi, Four Hands, Twisted (do we still call Bert that?  I favour MacGyver :-)) and myself.  Total attendence was around 40 racing enthusiasts and our instructor was expert, engaging and mixed up his slides with animations, videos, whiteboard sketches and some fun stories.

But most importantly, he reminded us it is HARD to get it all right, and even the pros don’t get it right all the time.  His funny stories about situations on board showed us that even the best of the best find themselves perplexed by situations that are very familiar to us.  But like the racing tactics we studied this winter, if we start to get things right more often than before (and more often than our competition), we will come out ahead!

So, what did I learn today?

Trim to the verge of stall

We do this with the spinnaker all the time (easing until it just starts to curl).  We should do this with the jib and the main.  For the mainsail, the tell-tales sneak behind the main about 30% of the time (more at the top).  For the jib, we should install leech tell-tales too, so that we can do the same for the foresail.  In this mode, we are getting the maximum lift/drag ratio from our sailplan.

Steer to see the inside genoa tell-tale lifting

Yep, just like we learned this winter, but Geoff suggested we add more tell-tales to the sail, one behind the other to get a sense of how close we are to the edge of stall.

How to set the outhaul

In 2017 we sailed with the main backwinded a lot by the genoa.  During 2018, we got this mostly under control by flattening the main through the outhaul, backstay and mainsheet.  But that leaves the question: have we done enough? have we over-done it?

Geoff explained that when the mainsail has too much depth, it becomes impossible to trim the main to avoid simultaneously luffing at the luff and stalling at the leech. (yup, we had that for sure in 2017).  The best spot for the outhaul is when you can stall the mainsail right at the point where the luff of the mainsail begins to quiver.

How to depower the sailplan

There’s a well-defined sequence to this.

  1. First we flatten the sails
    • Tighten the Outhaul
    • Harden the Backstay. And tightening the backstay has multiple effects (opens the leech, moves the mainsail draft aft, tightens the forestay, moves the genoa draft aft), so we need to compensate by
      • Harden the Mainsheet
      • Ease the Traveller
      • Tighten the Cunningham
      • Tighten the Jib halyard
      • Ease the Jib cars
  2. Second, we sail higher, feathering more often (ie: inner tell-tales straight up)
  3. Only when that is not enough, we decrease the angle of attack, by easing traveler and mainsheet

It’s amazing how all the sail controls are connected.  Obviously, in a gust, we need to respond quickly with the traveler or sheet, but our ultimate goal should be to rebalance the boat with the above steps 1, 2, 3 so that gusts aren’t as disruptive and we keep the keel working to push up upwind.

How to depower even more

In bigger wind, we need to go even further, because steps 1, 2, 3 will eventually lead us to a situation where the genoa is backwinding the mainsail, the gusts are turning the mainsail inside out, and we can’t point high any more.  (Yes, this is very familiar on PERSPECTIVE.)  The solution is:

4. crack the jib in high winds.  Yes, we will feather more, and the genoa will be luffing, but in this situation, the trailing edge of the mainsail will be drawing, and the power delivered to the boat will be better balanced around the keel.

And wait, there’s more…

But I think this was already enough!  Let’s go sailing and try it out 🙂


Leave a Reply

Your email address will not be published. Required fields are marked *