Forgot password

Sail Trim and Weather Helm - An AI Response

  • 31 Oct 2026 18:49
    Quote
    Reply # 13765806 on 13759620
    Anonymous member
    Anonymous wrote:
    Bonjour
    Junk rig is far from mainstream and IA reflex mainly the mainstream context. The IA responds would be rather correct for a bermudian riged boat but it also doesn't know what a rig without jib may be....

    On a junk rig, we sail in a different manner. The power of the sail is directly monitored by the sail area because it is trivial to reduce or increase the sail area. So the triming of the sail to manage the power is, in the case of junk rig, a second order item and only used by "experienced" sailors. it is usefull but not necessary.

    At first way of thinking, if your mast(s)/sail(s) are corectly positionned. If you have too much weather helm reduce the sail area. If your boat is too slow and you don't have weather helm increase the sail area. 

    It's a bit simplified but in doing so you will not be very far from the truth. 
    Eric
    Ah, yes Eric.  I had meant to put that in - can't believe I didn't.  I have found that in most cases where people have too much weather helm, it's simply a case of that they have too much sail up!  (Or over-sheeted)  Sailors seem astonishingly reluctant to reef.
  • 25 Oct 2026 20:55
    Quote
    Reply # 13759964 on 13759258
    Anonymous member

    Hi Mike.

    If moving the sails forward using parrels—or any of the other methods you’ve been suggested—doesn’t help, in my opinion there are more drastic solutions you could try, such as this or  this

    Regards - Jan

    Edit: A small correction—the second option I meant to show is the one seen in the first photo of the Colvin Gazelle: simply adding a staysail. I’m not sure if a bowsprit would be necessary (rather yes). To start with, I would try to buy or borrow a used staysail and (carefully) rig it up just to see how it works.  Of course, you wouldn’t be able to have a fixed forestay;This test staysail would have to be dropped before tacking/gybing—or perhaps even rigged only when sailing on a one (starboard ? rather port) tack.

    These are just my own thoughts, so you should definitely discuss this with someone else as well.

    Last modified: 26 Oct 2026 12:15 | Anonymous member
  • 25 Oct 2026 15:13
    Quote
    Reply # 13759732 on 13759258
    Anonymous member

    This is Tanstaafl before I bought her.  Here she is on the shore opposite Chantier Allemande in Grau d'Agde, France.

    The sails are still on her, but the masts pictured have been replaced with PJR spec hollow spars approximately 1/2 meter higher.

    The sails are flat.

    Each mast has a slight forward lean, but lean is limited by the geometry of the steel partners and the keel step.

    The original wooden battens were rotted by the time I bought her.  I was unable to find a suitable carpenter to make new ones so I have used aluminum alloy tubes in their stead.

    Runing rigging consists of:

    1.  Halyard

    2.  Sheets

    3.  Yard hauling parrel

    4.  Luff hauling parrel (top two panels)

    5.  Downhaul line.

    1 file
    Last modified: 25 Oct 2026 15:14 | Anonymous member
  • 25 Oct 2026 13:30
    Quote
    Reply # 13759656 on 13759258
    Anonymous member
    Hi Mike! 
    Please post us some photos of your yacht and its sails!  It will make it easier to talk.
    I’m especially interested in seeing the rigid batten parrels you have on your junk rig!
    Keep junking on the Luna!
    Last modified: 25 Oct 2026 13:54 | Anonymous member
  • 25 Oct 2026 11:57
    Quote
    Reply # 13759620 on 13759258
    Anonymous member (Administrator)
    Anonymous wrote:

    Please, at your leisure, take a look at it and let me know from your experience if it is good or if it needs further massaging to be a workable guide.

    Bonjour
    Junk rig is far from mainstream and IA reflex mainly the mainstream context. The IA responds would be rather correct for a bermudian riged boat but it also doesn't know what a rig without jib may be....

    On a junk rig, we sail in a different manner. The power of the sail is directly monitored by the sail area because it is trivial to reduce or increase the sail area. So the triming of the sail to manage the power is, in the case of junk rig, a second order item and only used by "experienced" sailors. it is usefull but not necessary.

    At first way of thinking, if your mast(s)/sail(s) are corectly positionned. If you have too much weather helm reduce the sail area. If your boat is too slow and you don't have weather helm increase the sail area. 

    It's a bit simplified but in doing so you will not be very far from the truth. 
    Eric
  • 25 Oct 2026 10:32
    Quote
    Reply # 13759597 on 13759258
    Anonymous member

    Sail trim can do little to correct griping in a hull with unbalanced lines. For example, a boat with a lean bow and heavy quarters will always gripe, irrespective of what you do with the rig, as soon as she begins to heel. I suggest getting hold of Dr Thomas Harrison Butler's book "Cruising Yachts - Design and Performance", where helm balance and the influence of metacentric balance is explained. 

    No doubt, AI will have scraped this work and will present it in an easily assimilable form, but take a look at HB's designs. Quite a few of his boats are still afloat. They are known to have remarkable self steering qualities. And above all, they are beautiful.
  • 25 Oct 2026 07:17
    Quote
    Reply # 13759555 on 13759342
    Anonymous member
    Anonymous wrote:

    You don't mention whether the sail is cambered.  If it's not, don't expect as close a tacking angle as you would get with a pointy rig.  You AI is correct that dumping the sheet will reduce weather helm: so will reefing.  There is no hard and fast rule, however, for two-masted junks.  They all behave differently: some prefer to have the foresail reefed first; some prefer the mainsail reefed first; some like them reefed at the same time. 


    The best thing is to take the boat out and experiment.  Mark both sheets with the sail hauled quite well in and then you can use that mark as it goes along the deck as an indicator, when you're finding out how hard to sheet in for sailing close-hauled.  You need to find the sweet spot between pointing and hull speed.  Once you feel you've got the boat sailing as well to windward as she will go, you can easily sheet in the sail in the future, using that mark.  Be aware, however, that she may sail quite differently on each tack.  Of course, your mark won't be much use once you've reefed :-(   

    Thank you Annie for your response.


    Tanstaafl's sails are of the PJR's form recommended in Fig. 2.26, page 30, 5 panels and a 2 panel fan, flat.


    I have been experimenting, but not only am I new to junk rigs, I am new to sailing, so I have no baseline experience from which to draw.  


    When sailing I know the importance of weather helm, but at times she's rounded up and I have trouble controlling the weather helm.  When speaking of wind vanes and autopilots everyone mentions the importance of a bit of weather helm and the need for the vessel to be trimmed to sail a course well before engaging either.  That's the prime reason I'm researching sail trim and weather helm.  Also, I've seen mention of sailors steering using their sails, and that is a topic related to setting proper weather helm, but the mechanics of doing that is something I need to learn.


    To my thinking the idea of keeping the fore sheeted more than the main makes sense since the main is larger, behind the CLR, and as such would be a larger lever pushing the stern around the CLR to make her round up.  If that is correct thinking it alone is a valuable piece of funadamental knowledge.


    Again, thank you.  I look forward to learning more.
  • 24 Oct 2026 20:07
    Quote
    Reply # 13759342 on 13759258
    Anonymous member

    Not to go into too much detail.  

    • Slacking the halyard is something you do only to reef and there is no reason to haul it bar taut.  You'll only have any luff tension under full sail, not once the sail is reefed.
    • Always keep the luff hauling and yard hauling parrels taut.
    • On a junk rig, you ease the sheet more like a foot at a time than an inch at a time.
    • Once the wind is comfortably abaft the beam, both sails can be squared fully away, ie with the yard at 90 degrees to the mast.
    • Don't sheet the sail too hard when going to windward, especially with a heavy, long-keeled boat like an Ebbtide.
    You don't mention whether the sail is cambered.  If it's not, don't expect as close a tacking angle as you would get with a pointy rig.  You AI is correct that dumping the sheet will reduce weather helm: so will reefing.  There is no hard and fast rule, however, for two-masted junks.  They all behave differently: some prefer to have the foresail reefed first; some prefer the mainsail reefed first; some like them reefed at the same time. 

    The best thing is to take the boat out and experiment.  Mark both sheets with the sail hauled quite well in and then you can use that mark as it goes along the deck as an indicator, when you're finding out how hard to sheet in for sailing close-hauled.  You need to find the sweet spot between pointing and hull speed.  Once you feel you've got the boat sailing as well to windward as she will go, you can easily sheet in the sail in the future, using that mark.  Be aware, however, that she may sail quite differently on each tack.  Of course, your mark won't be much use once you've reefed :-(   

    When running, some schooners like the main reefed first, some the foresail.  Unless the foremast has a good rake forward, the foresail won't stay asleep wung out in anything of a seaway.  In this case, it might be worth reefing one of the sails and sheeting it hard in, which will reduce rolling and stop the foresail gybing back and forth.  As to which sail you use: this depends on the boat.

    With so many different sail shapes and configurations, there aren't any really hard and fast rules fo junks.  I'm sure you'll soon get the hang of it and enjoy sailing your new boat.  Good luck!
  • 24 Oct 2026 16:31
    Quote
    Message # 13759258
    Anonymous member

    Good day everyone.  I'm pretty new to sailing.  I've done a few weeks sailing now with my junk rigged Ebbtide 35 from Grau d'Agde on the Gulf of Lyon down to Anzio, Italy.  I still have much to learn.  Though there are many who I could learn from about bermuda rigs, there a few available for junk rigs.  So, I made some queries to Google Gemini about sail trim and weather helm.  The attached file is the final response.

    Please, at your leisure, take a look at it and let me know from your experience if it is good or if it needs further massaging to be a workable guide.

    1 file