Barry Hayes, director of UK Sailmakers Ireland, aims for one of the most difficult sail settings to do correctly:
The setting of inhalers is often discussed before a race but rarely changed on a boat once set. Maybe it’s too hard to adjust them once the sail is set, or maybe they just don’t count after the cannon is fired?
Neither case is an excuse not to adjust your inhalers the same way you adjust your headsail threads as they are an important tool that must be adjusted when the wind speed changes between light and strong.
Inhalers: how do they work?
Classic boats have long tracks on their decks along which the jibs give the correct sail shape. You know, the witnesses chirp in unison. But newer boats, especially with non-overlapping jibs, can get a bit more speed by installing inhalers that move the lead position in or out rather than just back and forth. .
Optimizing the width of the gap between the sails can do a lot for speed. The next time you’re sailing behind a high-tech racing boat, see how far from the mast their jib is set. If they’re using such tight sheet angles, there has to be a good reason for doing it… and it’s not because it’s slowing you down.
Inhaulers were invented to pull the clew of the genoa or headsail inside to narrow the gap between the mainsail and the headsail. Aspiration has two main effects:
1. The narrower slot redirects airflow around the rear of the mainsail at a better angle, increasing the amount of airflow attached to the rear of the mainsail.
2. Airflow is compressed into the gap between the main sail and the headsail. This compression and slight slowing of the airflow forces the airflow on the leeward side of the headsail to accelerate into this void, increasing the speed of the airflow over both sails much like the way the airflow accelerates over the wing of an airplane.
Note that when pulling a headsail for it to work effectively, the main sail and the headsail must be adjusted together, so that the gap between them is balanced. The traditional “set-it-and-forget-it” approach is no longer good enough.
That said, compressing the airflow has both good and bad effects. Too much compression (inhaling too tight) overloads and chokes the cleft. You can see this in real time as the mainsail luff begins to reverse. You can use the backstay to flatten the mainsail over 12 knots to allow the slot to open, but this is not possible in light air below 8 knots. You will generally notice that this effect occurs in the 8 to 12 knot range on most boats.
PRO TIP: If you feel that the boat is moving slowly, don’t be afraid to relax the inhaler a bit and see if that increases the speed.
Too little compression at the slit too open, so the airflow is not directed to the rear of the mainsail, and the symmetry of the two sails will not work together, which will slow the boat down.
Knowing how much to inhale to apply is key; it takes time and practice to figure it out on any boat. Don’t be afraid to play around with your settings during a race or during a pre-race boat-on-boat tune-up.
Most boats have the tracks set on the deck at about 10 degrees or more, but you will find this ineffective for racing. We bring to close the angle of the sheet to 7 or 8 degrees. You can easily do this on any boat by measuring the clew point from the center line to the working angle of the sail.
PRO TIP: Keep an eye on the lines that control the inhaler. They can be subjected to a significant load and can be subject to wear. So over-building instead of under-building this system.
An important point for the uninitiated; the sheeting of the inhaler should not be done with any headsail. The sail should be designed to have extra twist in the leech to be pulled harder. If you haven’t designed the twist in the leech, you will completely choke the lunge and you won’t be fast.
You’ll notice this when pulling, and the leech is straight from the clew to the head as the sail was not designed with extra twist in the leech. Most retracted headsails have a twist between 13 and 15 degrees.
Precisely how much you bring back and under what conditions are different for each boat. Well, that’s the real question, isn’t it?
A boat with a long keel, for example, should not go inside 9 degrees, otherwise the boat would stop. The speed of the boat on the water also greatly affects the inhaler. The Cap 31, for example, can go up to 5 degrees because the balance of the lead allows the boat to do so.
It would help if you had a well-designed boat with the sails, keel, and rudder working perfectly together to make that angle. An older design boat would not maintain this tarp angle without the boat coming to a complete stop and sliding sideways. For example, a J / 109 might have an overlap angle of 7 degrees, while a First 44.7 would have a wider angle.