The Offshore Voyaging Reference Site

Rig Tuning, Part 5—Sailing Tune

To recap, in Parts 1 to 4 we:

  • Centred the rig athwartships—Part 1.
  • Set the rake—Part 3.
  • Set the prebend—Part 3.
  • Chocked the mast at the partners (keel stepped only)—Part 4.
  • Set the backstay/forestay to sailing tension—Part 4.

Now it’s finally time to go sailing and finish our tuning job. The good news is that, because we did such a great job before sailing and really understood what we were doing instead of just guessing or following a bunch of rules of thumb, this part is going to be easy, rather than the perplexing struggle that the sailing tune can degenerate into if the basics are not right.

In fact, all we need to do is:

  • Tighten the shrouds to sailing tension
  • Straighten the mast in the athwartship plane while sailing.

Easy-peasy, and should not take more than a couple of hours.

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More Articles From Online Book: Sail Handling and Rigging Made Easy:

  1. Six Reasons To Leave The Cockpit Often
  2. Don’t Forget About The Sails
  3. Your Mainsail Is Your Friend
  4. Hoisting the Mainsail Made Easy—Simplicity in Action
  5. Reefs: How Many and How Deep
  6. Reefing Made Easy
  7. Reefing From The Cockpit 2.0—Thinking Things Through
  8. Reefing Questions and Answers
  9. A Dangerous Myth about Reefing
  10. Mainsail Handling Made Easy with Lazyjacks
  11. Topping Lift Tips and a Hack
  12. 12 Reasons The Cutter Is A Great Offshore Voyaging Rig
  13. Cutter Rig—Should You Buy or Convert?
  14. Cutter Rig—Optimizing and/or Converting
  15. Cruising Rigs—Sloop, Cutter, or Solent?
  16. Sailboat Deck Layouts
  17. The Case For Roller-Furling Headsails
  18. UV Protection For Roller Furling Sails
  19. In-Mast, In-Boom, or Slab Reefing—Convenience and Reliability
  20. In-Mast, In-Boom, or Slab Reefing —Performance, Cost and Safety
  21. The Case For Hank On Headsails
  22. Making Life Easier—Roller Reefing/Furling
  23. Making Life Easier—Storm Jib
  24. Gennaker Furlers Come Of Age
  25. Swept-Back Spreaders—We Just Don’t Get It!
  26. Q&A: Staysail Stay: Roller Furling And Fixed Vs Hanks And Removable
  27. Rigid Vangs
  28. Rigging a Proper Preventer, Part 1
  29. Rigging a Proper Preventer—Part 2
  30. Amidships “Preventers”—A Bad Idea That Can Kill
  31. Keeping The Boom Under Control—Boom Brakes
  32. Downwind Sailing, Tips and Tricks
  33. Downwind Sailing—Poling Out The Jib
  34. Setting and Striking a Spinnaker Made Easy and Safe
  35. Ten Tips To Fix Weather Helm
  36. Running Rigging Recommendations—Part 1
  37. Running Rigging Recommendations—Part 2
  38. Two Dangerous Rigging Mistakes
  39. Rig Tuning, Part 1—Preparation
  40. Rig Tuning, Part 2—Understanding Rake and Bend
  41. Rig Tuning, Part 3—6 Steps to a Great Tune
  42. Rig Tuning, Part 4—Mast Blocking, Stay Tension, and Spreaders
  43. Rig Tuning, Part 5—Sailing Tune
  44. 12 Great Rigging Hacks
  45. 9 Tips To Make Unstepping a Sailboat Mast Easier
  46. Cruising Sailboat Spar Inspection
  47. Cruising Sailboat Standing Rigging Inspection
  48. Cruising Sailboat Running Rigging Inspection
  49. Cruising Sailboat Rig Wiring and Lighting Inspection
  50. Cruising Sailboat Roller Furler and Track Inspection
  51. Download Cruising Sailboat Rig Checklist
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Reed Erskine

You didn’t address mast “pumping”, which is a problem that occurs with the springy masts of some race/cruisers. What does it indicate, and how to deal with it?

A good observation position for mast performance under challenging conditions (i.e. plus/minus 20 kts) is beneath the V berth hatch, which, on many boats is positioned in a way that affords a comfortably dry and stable observer a perfectly centered view of mast and shrouds to check dynamic tuning
Reed Erskine s/v Cayenne

Marc Dacey

John, we have running backstay tangs on our cutter’s deck-stepped mast (and somewhere in a box are the running backstays), but we’ve yet to install them as we have two fixed backstays to the stern quarters and I haven’t seen the need. We soon will, however, see the need. Do you know of a reference which drills down to the right time and method to use running backs? I’m not seeing a lot of literature on the topic, although I may be posing the search query incorrectly.

Marc Dacey

Thank you for the replies, John. I guess I’ll dig them out and rig them.


Hi John,
Four comments on the topic “rig tuning under sail” (great article by the way)
Forty eight comments on the topic “reducing generator run time.”

Do I sense an expression of priorities here?

Speaking of priorities, I just looked at an owner built Fraser 41* that is the perfect example of what happens when a craftsman designs and builds a boat without sailing across an ocean first.
** Beautiful built-in piano and desk along the stbd. side of the salon.
** Sea berths deleted in favor of artistic curved seating.
** Full length valances along the trunk cabin sides to contain full length curtains for marina privacy.
** Complete absence of handholds inside and out (the builder must have gone to a boat show and copied the work of an Interior Desicrator who designed the interior of a 2018 production sailboat.)
** Transom and companionway sill cutaway to a 2″ high sill leading to the interior

* For those of you who are not Canadian, the Fraser 41 is a design that is similar to a Gen II Valiant 40, rarely has blisters, and good ones often come on the market in the low 50 USD’s. A lot of owner-builds– some great and some ordinary. Poor man’s Adventure 40?


I think there are 60+ Fraser 41’s afloat and voyaging throughout the Pacific.

Jim Evans

Super series, John. Wish I’d known all this thirty years ago – I would have got an unstayed mast sooner!


My mast is 48’ long on a 39’ German Frers Dufour design, with double spreaders, straight. When heeling 20-25 degrees, usually at about 20-22 kn apparent wind (next time I’ll read the true wind!) the masthead is sagging off leeward by about the mast width. This is has worried me for a long time. At some point I even though I needed to increase the cap shroud tension, but what ever testosterone I used, this did not help! So I went back to the more normal firm tension. You seem to think that all things considered equal this is rather a no worries. Do you have any more hint as how much is acceptable? There is almost no literature about this. The best I ever read was « the masthead can go gently leeward ». How much is gently ?

Charles Ethridge

Hi John.

If I initially set all the shrouds to eliminate wow, but then when sailing, set the lee shrouds to “just firm”, won’t that re-introduce a wow on the opposite tack or when not sailing?

Charles Ethridge

I think I see the answer to my own question, but it is non-intuitive (to me at least). I had to re-read Illustrated Sail and Rig Tuning by Ivar Dedekam pages 71-76 where he talks about tuning the rig under sail, and then especially page 78, where he talks about pre-tensioning the cap shrouds and why this is necessary to prevent shock loading the rigging.