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Slow Sailing

Slow sailing is a Junior skill and an important one. The objective of slow sailing is to get to a fixed point in space (a dock, a man-overboard,
a buoy) with zero speed. The idea is to come in on a close reach course, where you have an accelerator and a brake.
With the mainsheet all the way out, the sail is depowered, and the brake is the wind and sea against the boat. Pulling in the mainsheet on the falls is the accelerator. You line yourself up on a close reach
course and sail to the target.

There are two skills involved:

1) lining yourself up on a close reach course to the target, and

2) slow sailing on that course to it.

Let's talk about hitting a buoy at zero speed, as it's the hardest of the maneuvers. When you dock, you usually have some room for error, as you don't have to get to a precise point on the dock. But wait, what about a busy Saturday where you have to thread the needle between the only two boats where there's any space between them to dock? If you can lightly touch a buoy on a slow-sail, you can do precision docking.

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Ryan Alder
I think 'maintain forward momentum' is the big one (once you get the concept of finding the right angle to the wind). I know I ha... Read More
Thursday, 23 June 2016 11:16
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Sailing Small Circles

Sailing Small Circles

Small Circles

This is one of the most difficult Junior skills, and it's quite important. But why is it important? In real life, how many  small circles are you going to do? Probably none, after you pass the Junior Test. But you probably will need to do fast turns upwind or downwind, and do fast tacks and gybes, possibly to avoid disaster (like hitting something). And maybe with newbie crew. Think about approaching the dock on a big south wind and getting turned in the wrong direction (like into the sea wall). That's what this maneuver is about. You may never do another full circle in your life, but you may need one or more of the maneuver's components.

The maneuver is also a stress test of your sailing skills. You have to do a bunch of things quickly and competently without time to think - they have to be instinctive. It's also a stress test of your crew communications skills for the same reason.

A real circle?

First of all, it's not really a circle. We think of it as looking like this, here counter-clockwise around a buoy:

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Recent Comments
Michael Sherrell
John, do the instructions vary by wind speed? What wind speed are these instructions optimal for?
Thursday, 07 April 2016 06:50
John Bongiovanni
I think in any wind speeds where small circles make sense (that is, approaching 10 knots and more). In talking to people, the one... Read More
Thursday, 07 April 2016 17:35
Michael Sherrell
No, I think this is great. Actually made me rethink my own technique, such as it is, for which, thanks!
Thursday, 07 April 2016 20:23
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How to Make the Most of your Weight in High Winds

How to Make the Most of your Weight in High Winds

During the summer months or during the addiction-satisfying winter storm sailing, you can often find yourself overpowered. I’ve also heard of this several times during senior tests where the tester “falls” overboard for the legendary single-handed man overboard, occasionally where the tester is “unconscious”, typically in something like 20 kts. As the wind comes up from a comfortable 10 kts, the full sailed Bahia and JY will begin to require a bit more leverage than hiking out supplies, depending on crew weight. This is the beginning of the wind range that requires, or at least benefits from, using the trapeze. If you’re comfortable with your crew and/or your ability to drive the boat, start to use this. It’s a lot of fun to trapeze while single-handing and is arguably the most fun you can have without flying the kite, but be prepared to swim on your first few outings.

As the wind increases further to the over 15 kt range, the challenge really starts to kick in. Depending on your and your crews weight and skill, you'll need to consider various ways to depower, the most obvious being reefing. If you're luffing your sail more than not, you should be reefed. Another way to depower your main sail, is to pull on your cunningham. As the wind comes up, you should also use your vang/gnav to flatten the sail and change the placement of your draft in balance with your additional cunningham. This is the standard sail trim and depowering technique. As you struggle to keep the boat powered and moving, you can start to ease your jib a bit. This has the tendency to twist off the top of the sail and allow the boat to breathe a little bit by opening the slot between your main and jib. Closing this slot is what causes the “speed bubble” in the main, due to the wind coming off the jib backwinding and the main. As you’re “more” overpowered, you can ease your vang/gnav to twist off the top of your main sail.

One of the things that I haven’t seen done often at CSC is changing the placement of the centerboard while sailing. It’s commonly thought, at least at first that your boat is “under control” if it’s upright, but in reality, your boat is only under control when you are able to make headway and able to maneuver in some capacity. For this reason, I suggest that when extremely overpowered (repeatedly capsizing or completely luffing), you try raising your centerboard a bit. If you look at the diagram, you can see that as the length of the centerboard is reduced, you allow the boat to slip sideways more, but at the same time, you’re reducing the rotational torque that it’s causing on the boat by reducing both its lever arm and area. This allows the boat to slip sideways more but also reduces the leverage and reduces the heeling “force.” Although you may immediately argue that this is hurtful to your ability to get upwind, it allows you to trim your sails as opposed to luffing. When your sails are luffing, the only force on them is to leeward. However, once your sails are trimmed and have some proper shape, you have a driving force forward. For this reason, it is best to trim your sails to your course, then trim your weight and centerboard to match each other in their torque (rolling force) on the boat. As the boat increases in speed, your centerboard will create lift, which will “lift” you to windward. This lift is proportional to your speed, so as your boat speed increases, your leeway will reduce dramatically. This is much preferred over the scenario where the overpowered boat drifts sideways and you can’t sheet the sails without risk of immediate capsize. 

In other words, if we focus on the rotation portion, the torque counteracting the wind and water comes from the crew weight (or the lead at the bottom of the keel in a keelboat). Torque is force multiplied by length, so getting your weight out of the boat more, such as being on the trapeze or hiking, benefits your righting moment dramatically. This is part of the reason sails are lowered when it’s windy, it reduces the heeling force (torque) on the boat. Likewise, you can do this by lifting your centerboard to “reef” your centerboard. This, like a reefing a sail, both reduces the area as well as the length over which this force is acting.

Another important thing that isn’t often mentioned around the club is the region around a beam reach that opens up in (very) high winds, which is affectionately called the zone of death (ZOD). The ZOD arises when it’s too windy to keep the boat upright with all your weight utilized to its limit on a reach. This is basically when you find yourself completely overpowered. In any case, the existence of the ZOD means that you are now limited to only upwind and downwind sailing and not too much in between. This is a result of a beam reach being your fastest and most powered up point of sail. When you’re sailing in winds with the ZOD, your next biggest concern, other than staying upright when sailing in a straight line, is getting between up- and downwind courses. To do this, you must make a smooth and decisive maneuver to bear away. It’s helpful to have your weight toward the back of the boat and have pre-eased the jib. Once downwind on a broad reach, you can relax a bit and steer for heel with the main eased a few feet off the aft quarter and ease in the gusts. The most important thing when sailing in these conditions is to keep the boat moving and flat. Once you have leeward heel, you will likely round up and broach, leading to your next chance to master the bear away. 

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Recent Comments
Michael Sherrell
1. So running downwind in high wind conditions, you're saying to keep the main close to the centerline of the boat, just eased a f... Read More
Thursday, 17 March 2016 07:32
James Clarkson
1. In high wind conditions, what you really want is control over the boat and the best way to do this is with speed. The more spe... Read More
Thursday, 17 March 2016 10:23
Michael Sherrell
On all our dinghys except the Laser, you don't raise the centerboard, you swivel it. A little bit of it disappears into the hull, ... Read More
Sunday, 22 May 2016 20:32
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Demystifying Apparent Wind - Part 2

Last time, we looked at apparent wind and how it changes as you change point of sail. In that discussion, the speed and direction of the true wind was the same and the boat direction changed. Here we look at what happens when you're keeping the boat course the same, the wind direction doesn't change, but the wind speed does. It increases (a puff) or it decreases (a lull). You get both of these as you're traversing the Novice Area on a normal day (westerly winds), as the trees and gaps between them on the breakwater to the restaurant cause this uneven wind.

Again, we're using our Bahia-like dinghy and a 5 kt. wind. You're sailing close-hauled, so it looks like this:

b2ap3_thumbnail_Apparent-Wind-Puff---Close-Hauled.jpg

The boat is 45 degrees to the true wind, but only 30 degrees to the apparent wind. Normal. Then you get a puff, say a pretty big one (10 knots, double the speed but out of the same direction). In that instant, your boat speed doesn't change (it needs time to do that), but your apparent wind does. It looks like this:

b2ap3_thumbnail_Apparent-Wind-Puff.---Puff.jpg

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Michael Sherrell
The point being that when you get a puff you can head up and sail closer to the true wind, i.e., get upwind faster, rather than si... Read More
Monday, 22 February 2016 10:35
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Demystifying Apparent Wind - Part 1

Demystifying Apparent Wind - Part 1

A very common problem my students have voiced is that they have trouble figuring out where the wind's coming from. On the one hand, it shouldn't be so hard - turn your head and feel the wind on your ears. When it's the same on both ears, you're either looking straight into the wind or straight away from it. Or (less accurate) look at the yarn on the side stay.

Yet it's not so simple. You think of the wind as coming from the same direction, but when you sail, it doesn't seem to do that. It seems to shift a lot. And "you told me we couldn't sail higher than about 45 degrees into the wind, but that yarn on the stay has a much smaller angle than that". And (yet more observent) "We're sideways to the waves, so we should be on a beam reach, but the yarn says we're still somewhat upwind".

Welcome to the world of apparent wind. This is a simple concept to explain and  understand at a high level, but very hard to get at a detailed level. Everyone gets the simple explanation - you're peddling a bike at 10 knots on a calm day, what do you feel? A 10 knot headwind. The speed you're generating adds to the wind speed to create the wind you feel, the apparent wind. The apparent wind is what you and the bike feel. Peddaling 10 knots in a 10 knot headwind, and you're pumping against a 20 knot apparent wind. Doing the same in a 10 knot tail wind, and Bob's very much your uncle.

Those with a math background easily grasp that this is a vector algebra problem - the boat wind speed adds up with the true wind speed as vectors, where both the speeds and the directions interact. But even if you get that, it's truly hard to see how it all plays out on the water. And I'm speaking as someone with a graduate education in mathematics. In editing this blog, I realized that I had messed up a calculation in my first draft. If you sit down to do the calculations, you have to determine what your boat speed will be at a given true wind speed and point of sail (angle of the boat to the wind). Polar performance diagrams will show this, but good luck finding these for any of our dinghy's.

So my point is that it's quite difficult to build a mental model of this. Instead, you can get a feel of how it happens on the water without trying to understand why, exactly. I did the math from a guess of a polar diagram for a boat similar to a Laser Bahia at 5 knots wind. If you're not racing, it doesn't matter how accurate this is. But it should be pretty typical.

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Recent Comments
Michael Sherrell
The yarn on the shrouds will also tell you the precise apparent wind direction, in anything over a few knots.
Tuesday, 01 December 2015 13:07
Nathan Ilten
It would be a great senior project for someone to make some polars for our dinghies! There are enough people in the club with GPS ... Read More
Tuesday, 01 December 2015 23:06
Michael Sherrell
What is a "polar"?
Wednesday, 02 December 2015 07:36
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