You’ve got on the boat, you see all these lines everywhere and now you need to make the boat go forward. There are two or three things to understand about turning wind energy into forward energy on a sailboat. We call this process, “trimming the sails.” To keep things simple, I’ll only discuss making a sloop go forward.
The Angle of the Wind
Before I start putting words on actions, here is a diagram of different wind angles assuming that the wind is coming from the top. The first thing you’ll notice is that if you draw a line down the centre, it’s pretty much a mirror left and right.
Starboard Tack
Port Tack
For the moment, don’t worry too much about “Starboard Tack” and “Port Tack.” It has more of an impact when we talk about give way and stand on or to describe which side of the boat the wind is hitting. The important part is the names of things.
In Irons
At the top or 12 o’clock, you have “In Irons.” The main thing you want to remember about this one is that no matter how much you pull in or ease (sailor for let out), you can’t convert the wind into drive and make some power. If you want to go somewhere that would be straight up wind, you will have to bounce from one tack to another. Another way of calling this is beating up wind.
Close Reach
The reaches are a place where we often sail. The close reach is quite high up on the wind. For the more technical people, between about 55˚ to 90˚ off the wind. For people who like to feel the elements, if you’re looking at the bow of your boat from the stern, the wind will be hitting your face and the forward portion of your ear.
For trimming your sail, it will be quite tight in. The main sheet will be almost in the centre and the vang or kicker will be on almost as tight as it can be. As for the head sail sheets, the leeward side (the side that is downwind) sheet will be the working sheet and it will be ground in very tight to pull the sail into the boat. The windward sheet will be what we call a lazy sheet and have no tension on it.
Beam Reach
You feel the wind hit the side of your face. This is the beam reach which hits the boat perpendicularly. If the wind is constant and you’re doing a round trip, the dream is to be on a beam going to come back on a beam. The boat has a nice speed and is quite stable.
The best way to trim for this point of sail is to let the boom out about 45˚ or until it is aligned with the stern corner of the boat. This will help create a reference point of roughly where your sail should be. As for the head sail, it should be roughly halfway out.
Broad Reach
The same way the close reach has quite a wide scope, the same goes for the broad reach. It represents the area of 90˚ to 175˚ off the wind. This means the wind is hitting the back of one ear. This is my favourite way of having the wind behind me. It avoids the worry of the accidental gybe all while getting you to where you need to be.
Your sail on a broad reach will be almost fully let out or, depending on the boat because of shrouds and spreaders, completely out. As for the head sail, it will be almost fully out too.
Dead Run
This one is the easiest to understand how the wind “pushes” the boat through the water. With the wind right behind you, the sails catch it and push the boat forward. On the diagram, I showed the sails on opposite sides as this is the only point of sail they can do that on. If it isn’t done, the head sail is effectively useless as the main sail will be catching all the wind and shadowing the head sail like a building stops the sun.
The sails will be trimmed completely out. The main sheet will be allowed to run through and the head sail sheet will have just slight tension to keep the shape of the sail. If you have a traveller, it will be set completely to the leeward side. Just don’t forget to switch it over when you gybe.
The Ones Not in The Diagram
To keep the diagram simple, I omitted two often used points of sail. To not let you down, here they are!
Close Haul
I mentioned beating up the wind earlier. When you do so, to keep as close as possible to the wind, you will be close hauled. This means both of your sheets will be as tight as possible. If you have a traveller, it will be set completely to the windward side to help bring the boom to centre as much as possible. The boat will most probably be healed over if you have a good breeze.
Training Run
This is basically like a cheat code in a video game but for sailing. The training run is almost identical to a dead run but slightly up wind. It reduces the risk of an accidental gybe and allows you to be more confident about the slight inaccuracies helming can bring. The way to do it is to come up a couple of degrees so that the wind hits the stern slightly more to one side than the other.
One More Thing
In the same way Apple keeps the best for last, here is the ultimate tip to trimming your sails because every boat is slightly different.
Main Sail
If you think your main is too tight (too far in), ease it out until it flaps slightly and pull it back in until it stops. That is the best way to get a nice trim.
Head Sail
The head sail has an extra trick up its sleeve. Almost all of them have telltales. If the ones on the inside are flapping everywhere, pull in on the sheet. If it is the ones on the outside of the sail, ease it out. The let out until it flaps trick also works but the telltales do a better job.
Now you can go out and try it all in the real world! The best way to fine tune sail trim and make those sails as efficient as possible is to work it out when you are on a boat and do it as many times as possible. If you want, NauticEd offers a great course here to help you understand it all.