Sailing Term Spotlight: Outhaul

What It Does and Why It Matters for Sail Shape

The outhaul is one of those sail controls that seems simple — it just pulls the clew of the mainsail along the boom — but it has a big impact on how your boat sails.

If you want better speed, more control in different wind conditions, or to look like you know what you're doing when someone says “ease the outhaul,” then this one’s for you.

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What Is the Outhaul?

The outhaul is the line or strap that pulls the clew (bottom rear corner) of the mainsail along the boom.

• Pull it tight, and the sail becomes flatter.

• Let it off, and the sail becomes fuller.

It adjusts the sail’s depth, which controls how much power the sail generates — especially in the lower half.

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Why Adjust It?

Flat Sail (Tight Outhaul):

• Better for strong winds

• Less drag

• Easier to depower

Full Sail (Loose Outhaul):

• Better for light winds

• More power

• More lift

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When to Use It

• Before racing: Set it according to the forecast.

• During sailing: Adjust between upwind and downwind legs if your boom setup allows.

• When overpowered: Tighten it up and flatten the sail to regain control.

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Top Tip:

Mark your boom with small indicators for “tight” and “loose” outhaul settings, so you can make quick, repeatable adjustments.