The fast teams in any class are always making tiny adjustments in the sheets, steering and weight all the way around the race course, but can you explain why? When it comes to boat speed, no topic is more important than understanding rhythm between these three critical adjustments, and yet most sailors never receive any formal instruction on this topic. Both under powered and over powered conditions, rhythm is one of the most important topics to understand, and until this technique is sorted out, all other boat speed topics are secondary. Rhythm is all about making the things that you can control - steering, weight and sail trim - match the things you can't control - sea state, pressure and apparent wind - so first let's think about the natural rhythms in sailing that we're trying to match.
Sea State, Wind & Apparent
It might go without saying that when we adjust sheets, steering or weight, this generally has to do with a change in sea state, wind, or apparent wind, but let's dig into this to really understand how these factors work together to create a natural rhythm to boat speed.
The most obvious rhythm that we need to be in sync with is sea state. We usually categorize sea state as being flat, choppy, or wavy, but within each of these three categories there is an infinite amount of variation, and often times we see all three on the same course. Visualize sailing up a race course. First you encounter three steep pieces of chop in a row. As you hit each one, the boat smashes into the water ahead, slowing abruptly, and then re accelerating after each. Next you encounter a wave, climbing the face gradually, and surfing quickly down the back. Next you get to a flat spot, where the boat can really accelerate. Each of these factors has a different rhythm depending on the angle that you hit them, the size of each, and your speed through the water. Here are a few generalizations that can help you understand sea state rhythm:
- Chop: Generally stops the boat abruptly, then the boat re-accelerates smoothly
- Waves: Generally slow the boat gradually as you sail up the face, and then accelerate the boat quickly down the back, causing the boat to spend more time on the face, and less time on the back.
- Side Waves: Generally a long power build up the face of the wave, and an abrupt power decrease down the back, with less speed change than a head-on wave
- Flat Water: Generally allows the boat to keep accelerating until the foils and hull run up against their efficiencies.
Puff-Lull sequences are present on just about every race course, and can take many forms. Understanding whether puffs and lulls are predictable, or whether they are impossible to see is critical to understanding rhythm on the race course. Remember here that it is just as important to acknowledge when puffs are impossible to call, as it is to try communicating them when you see them clearly. If you don't feel confident in your ability to call pressure on any given day, chances are good that apparent wind will play a bigger role in rhythm than true wind.
Apparent wind is a function of both sea state and true wind, but is often more predictable than either, so this is one of the most important places to focus your energy when understanding rhythm. The more efficient your boat is, the more of a difference apparent wind can make because the more it will change with small changes in true wind and sea state.
Wrapping your head around this topic is crucial for really understanding the "why" in the next section. When you're feeling good about it, take the quiz below, to figure out where you stand on the topic, and what questions you need to ask.
How Does This Effect Technique?
Okay, so we have reviewed some of the rhythms in the race course environment; now how can we take advantage of this knowledge to improve boat speed? The key here using what we know to anticipate changes in pressure, and make small, precise adjustments earlier to eliminate the big clunky adjustments later.
Let's take what we know about the rhythm of chop and apply our technique. When we hit chop, immediately our boat decelerates which causes our apparent wind to shift aft and decrease. This will mean that we have less pressure in the sails, and if we don't adjust sail trim, we will end up too tight on the sheets. The boat passes the chop, it slowly re-accelerates, causing apparent wind to gradually and continuously shift forward until the boat is fully up to speed. We will feel more pressure as apparent wind increases, and will need to trim the sails in slowly and smoothly to account for the forward shift of apparent wind. As a result, our technique for hitting chop in under powered conditions is to ease the sail quickly and move weight in to compensate for the chop, then smoothly re-trim and move weight out as the boat re-accelerates. We could say that the rhythm is, "Quick in, slow out."
Contrast that to sailing over a wave. As you head up the face of the wave, the boat slowly decelerates, requiring the boat to either head up or ease the sails. The boat might feel more load in the sails here as true wind speed increases close to the top of the wave. Down the back, speed will surge, apparent will shift forward, and load may drop. As a result, rhythm is probably, "Slow out, quick in."
In under powered conditions, it's important to keep in mind that the sail trimmers are driving the boat (in skiffs this means the crew!). The sails are our engine, and while heel, and steering are both important factors in getting the most out of that engine, if the engine itself, is out of tune, there's little else we can do with steering and weight to maintain speed. You can remember this as, "Sails lead weight and steering." When you have video from outside of the boat, a big feedback loop to pay close attention to is whether sails are leading weight, or weight is leading sails. This is true in both over powered and under powered conditions.
Examples In Various Conditions
Under powered example: In under powered conditions when the boat looses power, we want to ease FIRST, as weight swings in - too often we dive in with weight while keeping sails choked, in hopes that the boat will just power up again. This comes back to making small adjustments more frequently, as this is usually a bigger sign that we needed to ease slightly five seconds ahead of time, but didn't feel the drop in pressure soon enough.
Over powered example: In over powered conditions if we start steering up as a puff hits without trimming main sheet on, we loose pressure on the leech of the main sail, and when the puff begins to fade, inevitably we trim on the main sail, the boat doesn't respond, and we end up crashing to windward, pulling on the helm to get the bow down, and losing half a boat length. This is a result of feeling the pressure gain from the puff too late, and responding to the big change rather than starting early with the tiny change. If we respond early, we feel the initial pressure gain, and we trim on to anticipate the boat's acceleration and therefore the forward apparent wind shift. If pressure continues to increase we might need to ease momentarily to keep the boat flat, but immediately begin trimming on again to anticipate the forward apparent wind shift.
Practice, Practice, Practice
A few great rhythm drills that you should be incorporating into training are:
Rudderless sailing - Ingraining a deep understanding of apparent wind, and how the boat responds to sheet and weight adjustments is critical. When you pull the rudder out you get immediate feedback.
Heeled to windward sailing - For honing the overall anticipation mechanism this is a good exercise that delivers instantaneous feedback.