RSYS/North Sails webinar 1: Mainsail Trim

RSYS Captain Karyn Gojnich introduces Alby Pratt and Andrew Parkes who share their tips for optimal mainsail trim in this first in a series of 7 weekly webinars.

[@kathveel53]

A fantastic presentation, clear explanations and great visuals. Thanks for posting!

[@michelefrost4338]

Leave it to a bunch of Aussies to teach me to sail and guess what......I learned the finer points of sail! Congrats, this is a GREAT VIDEO! YA'LL SHOULD GET AN AWARD FOR IT!

[@paularkwright1795]

Thanks so much for this - spent years seeing (and wondering about) all this happening on the boat, brilliant to have the theory explained so well.

[@lisapalethorpe8499]

Thank you so much North Sails and Royal Sydney Yacht Squadron - these recordings of your Zoom sessions are just fabulous! I have learnt so much and they are really engaging. North Sails simulator is really helpful. RQYS Brisbane

[@yachticus]

many years ago I complete the North U sails course - both trim and fast - you guys have improved on that - really well done

[@dnallerzwaersten]

From the Philippines, Great tutorial in combination with the simulator. All makes a lot more sense now. 👍

[@EpoxyCircus]

So nice to have the information available

[@dees9502]

Well done ✌️ 🇺🇸 🇦🇺

[@jossteenbrugge5555]

Thanks from The Netherlands great tutorial and top visualisation

[@andrewparkes9369]

Hi Jos, Thanks for your feedback. I'm glad you enjoyed it.

[@gkelly941]

Excellent explanation of the dynamics of mainsail trim. One important point about boat set-up is how prebend relates to the other controls. Many sailmakers have tuning guides for different boats that explain how to set this up for different wind velocities. This usually involves the position of the mast butt, the blocking at the partners, and the headstay length, so that you will have the right amount of mast bend for the sail design and conditions in a neutral setting.

[@gkelly941]

Another key is to have gauges on the boat for backstay, halyard and lead positions, so you can repeat your settings. These can be as simple as tapes with numbers on the deck, or a batten with numbers next to the backstay ram.

[@Themothershipsailing]

Hi Andrew - excellent overview, thanks. I’m an Aussie living in the Netherlands, so nice to hear an Aussie accent! I have a 1974 Swan 38.. two questions - when can I see that I have the right amount of backstay on? Are there differences in main trim with older boats like mine that have huge overlapping headsails and smaller mains? ie.. is creating the slot the same? North’s here made my new set of sails and they’re stunning.. just need to get more proficient at using them!

[@ot4627]

"Slow as a wet weekend" is probably my favourite comment hahaha

[@mayadare4087]

Hi, great informative video. I have just helped sail a new Jeaneau 60 up the coast to Cairns. I have sailed many years on a J35 and understand the setup for that type of boat but as the Jeaneau has an in mast furling main & a set backstay, many of your tuning points can not be done such as traveller, backstay & Cunningham. As the owner would like to race the boat up north, how would we apply the changes to still get the best out of the boat.

[@OzzeyfromVek]

good resource

[@bobk9412]

great video. when sailing apparent beam reach with asyo, is backstay used the same as when close hauled?

[@gkelly941]

No. When sailing on a reach, particularly on a boat with in-line spreaders, the backstay is used primarily to set the fore and aft position of the rig, in order to control the helm. This effect will be less if your boat has swept- back spreaders than with spreaders that are in-line with mast. Also, as the main moves away from the centerline, fore and aft mast bend does less to flatten the draft of the mainsail, and the outhaul does more to flatten the sail, particularly the bottom third.

[@jameslittlewood7663]

Vang-sheeting seems most useful from cracked sheets to beam reach, with vang control not only constant, but - in puffy conditions - highly active. Also, interesting that you'd trim sheet before traveller, upwind. Doesn't traveller adjustment have the benefit of powering on/off, without changing the major sail shape?

[@gkelly941]

Yes, but.... After the main is eased, the boom is no longer above the traveller, and then easing the vang is the only way to ease the trim in the top of the main, particularly when you are reaching in puffy conditions and need to de-power in the puffs.

[@crapisnice]

i use esail simulator with sandbox testing all wave heights and wind speeds

[@af9126]

"North U Sailing Trim Simulator". 👍

[@jareklyszczek986]

Thank You very much for very informational webinar. Does this sail trim work in similar way in northern hemisphere? ;) Like in Baltic Sea? Greetings from Poland :)

[@andrewparkes9369]

Hi Jarek, Thank you for your comments. Yes, these principals apply in both hemispheres and the Baltic Sea too.

[@jareklyszczek986]

@@andrewparkes9369 ;) But seriously - than You once again :)))

[@ji6050]

North 👍

[@eventhisidistaken]

It appears that the North U simulator is no longer available on google play store...or has it been renamed?

[@BarringtonOASmith]

If you don't have a backstay adjuster, and it's not convenient to operate the turnbuckle, what's the best way to to get rid of the luff in the main caused by jib backwind? No cunningham either. The boat is close hauled and the jib is set correctly because the stripes look good and the tales are streaming. But the main is backwinding.

[@PhilipCatley]

Pull traveller to windward, opens the slot between main and jib. Then ease the mainsheet to twist off.

[@gkelly941]

Think about spending a few guilders to get a hydraulic backstay adjuster with integral pump, so you can adjust the headstay tension and mast bend with one control, which will make a huge difference in making your sails more efficient.

[@eventhisidistaken]

Choose from the following, as best you can: - boom vang on (if you have one) - pull the main in even tighter, move traveler to windward (if you have one) - move blocks on the jib track forward (if you have a track). Start with the lazy side, then tack when convenient and get the other side - tighten the outhaul (even sunfish have these, if rigged for racing)...tough to do on a bigger boat in the middle of a race. You'll probably have to wait until a downwind leg or maybe even do it between races. (if you have an extra crew member, they might be able to do this in the middle of a tack while the main briefly luffs) - ease the jib an inch at a time until main sail shape looks right. you may have to fall off ever so slightly as you do this, but you'll get a lot more speed to make up for the pointing loss

[@madario]

How do things differ when you have a square-top mainsail?

[@user-xw9hx6lf5p]

Hello! I want to make subtitles to this video for my language. Can you give the permission?

[@hotelpousadaportomilenio3502]

Is the simulator available somewhere on the Web?

[@TheFlyingPlectrum]

backstay on makes the main deeper surely?

[@andrewparkes9369]

Hi David, The backstay bends the mast and reduces depth, please feel free to ask any other questions.

[@jameslittlewood7663]

Flatter but with more twist

[@yachticus]

also drops the head of the sail to leeward - depowering

[@gkelly941]

@@yachticus, if your shrouds are tensioned correctly, backstay tension will only increase fore and aft mast bend. This may ease the leach slightly as the masthead moves aft, so be ready to bring in the sheet when you pump the backstay.

[@gkelly941]

Increasing backstay Tension increases mast bend on many boats. This moves the luff further away from the leach of the sail, which in turn reduces the depth of the sail. Increasing backstay pressure also reduces headstay sag, which has a similar effect on the headsail.

[@xavpil2]

where can we get the simulator?

[@Thomas-dp8eb]

Pretty sure it's north sails trim simulator, it's about 10$

[@bricktopperheadon5490]

The apple and android apps appear to be gone. I downloaded the pc version (free) from the north sails website, downloads section.