Headsails Trimming

by Paul Eldrid OneSails Australia

V.1.0

Congratulations!

Your new OneSails Jib or Genoa has been designed specifically for your boat using some of the best software and talented sail designers in the world.

It has also been crafted from the finest materials and built with the precision of OneSails passionate sail makers. Your local OneSails representative will be happy to assist you with setting up your new sail.
Before we get started, there are a few important things to consider:Your new OneSails Jib or Genoa has been designed specifically for your boat using some of the best software and talented sail designers in the world. It has also been crafted from the finest materials and built with the precision of OneSails passionate sail makers. Your local OneSails representative will be happy to assist you with setting up your new sail.
Before we get started, there are a few important things to consider:

    1. Go to www.onesails.com and download the Dede Sailing Diary. Every time you go sailing you could be recording valuable information that WILL help you improve your boat speed and performance over time.
    2. Caring for your sails is important! Release the leech cords, foot cords and batten tensions after you sail each time. This way after racing your sail will ‘relax’ better while it waits for its next race.
    3. Never fold your sail in the same place every time – try and avoid hard fold points.
    4. Try and store the sail completely dry and in a dry place.
    5. Never stow a sail in a crumpled or crushed manner.
    6. If your sail has hanks lubricate them every 6 months to prevent corrosion.
    7. If the sail has a foil tape inspect and trim the top part to ensure smooth feeling into the foil.
    8. Regularly check all telltales and leech ribbons are in good order – without these trimming is difficult.
    9. Make sure the sail is used in its designed wind range as taking the sail outside the range can lead to premature aging or even failure in extreme cases.
    10. Take tape and marking pens with you when you sail. Calibrating your boat is very important for your on board reference and also to record later in your Dede Sailing Diary.

Eldrid super tip - By keeping a sailing diary you can learn the best settings for your boat and your sails which improves your boat speed.  Involve all of your team in writing some notes after every time you sail and you will soon have a detailed database.  If you then need to discuss your performance or new sails with your OneSails sail maker you have all the information you need.

Luff (Halyard) Tension

デザイナーはセールに最大ドラフト量とそのポジション、艇ごとに最適化されたエントリーアングル、使用風域、セールの材質や遭遇するであろうフォアステイテンション(バックステイによる)を設定してその設計を行います。.

一般的には、風が上がれば上がるほど必要なラフテンションは大きくなります。特にピンチングで走る際などは、非常に重要な要素です。これはセールへの負荷が上がるにつれてセールのドラフト位置が後ろにづれることに起因します。これはセールの伸び、フォアステイテンション(バックステイやフォアステイの調整による)、ジブカーの角度及びシートのポジションやテンションに起因します。

軽風域ではセールのラフに軽くしわが入る程度で大丈夫です。ただテンションを入れ過ぎると縦ジワが入るので気を付けてください。風が上がってセールの負荷が大きくなったら、ラフテンションを足してこのシワを消してください。セールの設計風域を超えるまでは、テンションを足して行きます。

しかし、オーバーテンションには気をつけて下さい。その状態でシートにテンションを入れると、セールの寿命に関わります。マーカーでハリヤードにマーキングするのは良い方法でしょう。これはレース時等でも、短時間で基準となるセッテイングに持っていくことが出来ます。

フォアステイの、テルテールウインドウの高にマーキングをし、セールのラフにもマークを入れる事で、より精度の高い目安となります。セールの伸びなどに対しても主観的でなく、ハリヤードの影響もうけません。ピットマンだけでなくジブトリマーもマークを見る事が出来るため、艇全体にプラスになります。

 

ラフテンションを加える事でドラフトは前に行き、ラウンドエントリーになります。上側のラフテンションが少ない時のシェイプと、そうでない下側の写真を見比べてください。

リーダー(ジブカー)ポジション

ジブカーは一般的に、前後に動かすことによってリーチのテンションとフットのテンションを調整します。リーチについてはセールのツイストが、フットはその深さが変化します。海況によってジブカーのトリムの方法も変わってきます。最初は、ラフの1/2の点がシートの延長線上に来るようにしましょう。セールの適正風域の下限では、ジブカーを前に動かしてセール下部をパワフルにして下さい。同時に十分にツイストさせ、セール全体を風が流れるようにしましょう。’.

風が上がるにつれて艇には十分なパワーが入り、ジブカーは徐々に後ろに下げられます。これによってフットは浅くなり、ツイストも増えます。これは二つの大きな変化を艇にもたらします。まずセールがフラットになる事によってひきずり抵抗が減り、セールの空力特性が向上して、艇が速く走るようになります。さらにリーチが適度に開くことにより、加速した空気がより早く流れで揚力が向上します。また、同時に抵抗も減り、メインセールへの影響も少なくなります。

ポイント –  ジブトラックにナンバーを付けることによって、それぞれのセールにとって目安となる位置からスタートできます。これは最初のホイストや混戦の中でのマークラウンディングでも、ジブカーの位置にあたりを付けられます。シートにテンションがかかった状態でジブカーを動かすのはほぼ不可能です。なので「あたり」を付けることにより、位置調整のためにセールのテンションを抜く事態を避けることが出来ます。

 リード位置を前にすることに寄って、軽風でのパワフルなフットとツイストを作れます。リーチのツイスト(赤)と、ジブセールとメインセールのスロットがクリアになっている点に着目して下さい。

まず最初は、ラフの1/2の点がシートの延長線上に来るようにしましょう。

Jib Sheet

Being the primary control on any sail the sheet is the most important and most frequently adjusted.  The amount of wind, the sea state and how the boat is behaving will determine how mush sheet tension is applied. The goal is to have the jib sheeted as close as possible for maximum upwind performance without being on too hard where the sail stalls and the boat slows dramatically. As a general rule as the wind increases, the more sheet tension is applied.

Too much when the wind is light and it will definitely stall.  Too little and the boat won’t ‘point’ (sail close to the wind).  Remember that the fins below you (keel and rudder) also need flow for the boat to work too!  When trimming the jib – go for boat speed first so your foils get a grip on the water then trim the sheet on gradually to get the height.  It is very important to do this in and out of manoeuvres, for example tacking and starting and also through changes in wind speed and in gusty conditions.

Eldrid super tip –  Look up! The most important thing to look for when sheeting the jib on is looking up to see the twist and how close the sail gets to the rig.  For overlapping genoas use the proximity of the sail to the end of the spreader as a guide to how much sheet tension you have. For light airs work on 5 – 10cm, medium air just touching to 5cm and heavy winds 10 – 15cm.  For non-overlapping jibs you will get great value from putting reference marks on your spreaders as per the image below. 

Overlapping jib with the sheet tension so the sail sits
0 – 5cm from the spreader tip(s) for medium air

Non overlapping jib sheeted at 8 degrees
note the spreader reference marks to indicate shee

Inhauler Position

Used on boats with non-overlapping jibs, the inhauler changes the position of the clew on the jib relative to the centreline of the boat. This effectively alters the sheeting angle of the jib in the quest to make the boat point higher to the wind.  The inhauler can come in two forms – either a transverse tracks (in/out tracks) or by a floating barberhaul line on a purchase system which physically pulls the jib sheet inboard between the clew of the jib and the fore/aft jib car. Inhaulers are only ever used when sailing upwind.

As a general rule in light winds you have the inhauler set almost all the way in allowing you to use soft sheet tension and make the bottom of the sail deep and powerful, while nice and twisted in the top without stalling it.  As the breeze increases and more sheet tension is applied the sail continues to flatten out as it is pulled on and set closer to the rig increasing pointing ability. Only start easing the inhauler when you are at the top of the sail range and you need to de-power. Make sure all other controls have been used at this time - maximum forestay tension (backstay), maximum halyard, Jib Lead (car) aft and the sail is as flat as you can make it.

Eldrid super tip –  Measure your sheeting angles off the centreline and put marks on the deck eg: 6o,8o, 10etc… not only do you have a good reference point but you can now record your log with definitive numbers and even discuss your sail trim more easily  with your OneSails loft! 

Inhauler in light and medium conditions increases pointing ability – be careful not to close the slot and stall the sail.  Talk to the mainsail trimmer to see if the mainsail is back winding too much

In heavy air you will need to let the inhauler off,
especially if the mainsail traveller is eased to leeward,
as this starts to close the slot between the two sails

Forestay Sag / Backstay Tension

As the sail loads with more wind the forestay will start to sag to leeward with this load affecting the depth (fullness) of the sail.  As we know a fuller sail is more powerful  so this can work as much for your boat speed as it can against you.  In lighter winds with forestay sag you can create a very powerful jib but as soon as the breeze increases the sail needs to be flattened not only with the jib lead position but also by tightening the forestay.  This is done on most boats by tightening the backstay which in turn tightens the forestay. On boats with running backstays this does the same thing.

As a general rule start with little or no backstay in light conditions to have the sail full and powerful.  As the wind increases keep tightening the backstay to flatten the jib.  The tension will also help your mainsail shape too.  Forestay sag is considered the enemy once the boat is powered up, as it effects how close the boat can point to the wind and adds unwanted depth therefore dragging the boat’s aerodynamic profile and slowing it down. Some modern race boats also have an adjustable forestay via hydraulic systems, whereas the same can be achieved on most yachts for sailing in specific conditions by adjusting the forestay before racing for set conditions.

Eldrid super tip –  Your backstay should be calibrated and if you are using a simple purchase system you can still use a tension gauge to record the load of your backstayfor each of your marks.  If your backstay is hydraulic – get to know how many PSI each of your marks is.  If you have a load cell be sure to record your kg settings in your Dede Sailing Diary!

Forestay sag (seen here against the blue line) can help you with power in light winds.
Increasing the forestay tension by pulling on backstay will flatten the jib.
You can also tighten the forestay for stronger wind, reducing the sag.

Telltales

Telltales are a reference as to how the wind is flowing across your sail. They should be used as a reference to your sails trim but not over analysed as the pursuit of perfect, even flow may see the sail trimmed without consideration for the power, heel angle, sea state and ease of steering for the driver.

As a general rule in light winds the goal is to have all telltales flying horizontal which indicates you have flow across the sail.  Approaching medium winds the telltales on the leeward side should be streaming straight, and the windward side straight to slightly lifting up to 45 degrees which is achieved by the driver keeping the boat up in the steering ‘groove’.  In strong winds the sail may need to be feathered by sailing high in the steering groove and the windward telltales will be lifting vertically.

Eldrid super tip –  In some conditions especially light winds it may be difficult to get all the telltales to ‘fly’.  Start at the top and work your way down – never sacrifice the top for the bottom! The bottom set are more for the driver  and the top and the middle are more for the trimmer.

Telltales in light air

Telltales in medium air

Telltales in heavy air

Conclusion

Like all systems in sailing it is best to keep everything as simple as possible. The more confident you become with your trimming skills, you will find yourself trimming more or ‘changing gears’ for conditions as they vary when you are racing. 

This, added with documenting your settings in your sailing diary will see your performance improve greatly.  For help, you OneSails loft is justa phone call away.

Sail fast and have fun! From the OneSails Team!

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