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LITTLE TO NO WIND

Sep 22, 2018
1,869
Hunter 216 Kingston
@Don Guillette

Thanks for starting this thread, interesting topic. :)

As I read the various posts I note that some of the various “tricks” are also useful in any wind strength. Calm - minimal steering, keep the wind attached to the sail through subtle trim changes, build apparent wind and keep it etc. are all things that make a sail propelled vessel GO.

Most of my “sailing” experience comes from windsurfing and smaller <25ft boats so I don’t presume to have any opinion on bigger boats other than the assumption that if the management of the vessel is conducted “smoothly” it will GO.

In windsurfing - windfoiling where your body is integral in getting it to GO - smooth, precise sailors will always outperform those who try to force it to happen. Now that I boat more than I windsurf I try to use a subtle technique whenever possible.

Thanks all for sharing your “secret recipes” :)
 

srimes

.
Jun 9, 2020
209
Macgregor 26D Brookings
Hope all you sailors are staying safe and Covid free.

Years ago, during a cruise to Australia and NZ, I met a SAIL TRIM FORUM lister in Auckland and we've kept in touch over the years. I think the Aussie's and the NZ folks are the best and most hospitable folks I've ever meet. A couple of days ago we were chatting about getting a boat moving in little to zero air.

Imagine you're closehauled and a few miles from your marina and the wind dies completely or to a whisper. One option is to start your motor but suppose your boat doesn't have one or your motor is not functioning. I'm a firm believer in always having a "sailing backup plan" - whether I need it or not.

Suppose, in these conditions, you knew how to get 1 or 2 knots out of the boat - you'd be home in a couple of hours. If you can get the boat moving forward, even a small bit, it's mass tends to keep it going even if only for a short distance at a time.

Knowing what you have to overcome to get the boat moving is the first step in solving the problem. The main problem is FRICTIONAL DRAG. Every square foot of the hull that's in contact with the water is slowing the boat down.The first step is to get all the weight on the leeward or low side and HEEL THE BOAT. Some additional hull will be in the water (mostly topside) but because the hull is rounded much more hull area will be out of the water. The less wetted surface equals REDUCED DRAG. Heeling also creates weather helm and the skipper, using a very light touch, can feel it in the rudder - it's LIFT.

Next, instead of letting the boom flop around and knocking what little breeze there is out of the sail, keep the boom on the leeward side.

Everyone on the boat should stay as low as possible to reduce windage. The skipper need to keep his head up a bit looking for dark patches on the water, which indicate a breeze. How many times in these conditions have you seen crew members standing at the bow or mast - they're adding to the problem. Unnecessary crew movement should be ZERO. Any sheet sail trim adjustment to the main or jib should be done with only the winch handle and ONE CLICK AT A TIME. Jerking the main or jib sheet will disturb any air flow you've captured.

If your direction to the marina is downwind does the procedure change? Not much but there are some additional things you can do. Heeling will help but this time heel to weather and place the boom to the weather side. The reason is that places the mainsail higher off the surface of the WATER. Wind velocity increases with every foot of altitude above the water surface -- the wind velocity is 60% greater at the top of a 30' mast than it is at deck level.

PUMPING the mainsail can get the boat moving. Grab the mainsheet or the boom and pull it as hard and fast as you can toward the center of the boat. Then let the mainsail out slowly and do it again -- and AGAIN until the boat starts to move forward. ROLLING the boat is another thing to try. If you have tiller steering SCULLING will also help to get the boat moving.

When you think about it, the above suggestions are just things most sailors would think of if they put their mind to it. Maybe some of you have other suggestions that might work.
Thanks for the timely thread! :beer:
This was fresh in my mind when I took the family out yesterday, 4-6kt winds in 4ft seas. We sat on the leeward side and kept the sails full. Maintained about 2.5-4 kts on the gps, which seemed OK to me for the sea state and 105% jib.

I've ordered a drifter and can't wait to see how it does!
 
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Apr 5, 2009
1,547
Catalina '88 C30 tr/bs Oak Harbor, WA
Thanks for the timely thread! :beer:
This was fresh in my mind when I took the family out yesterday, 4-6kt winds in 4ft seas. We sat on the leeward side and kept the sails full. Maintained about 2.5-4 kts on the gps, which seemed OK to me for the sea state and 105% jib.

I've ordered a drifter and can't wait to see how it does!
In those conditions, the 105% just might do better. the leftover slop plays havoc with big sails but the smaller ones might stay full through the roll.
 

RussC

.
Sep 11, 2015
1,519
Merit 22- Oregon lakes
In those conditions, the 105% just might do better. the leftover slop plays havoc with big sails but the smaller ones might stay full through the roll.
Depending on the weight of the cloth............... ;)
 
Jun 25, 2004
1,108
Corsair F24 Mk1 003 San Francisco Bay, CA
Even In a “dead calm”, there often are some vertical up and down draft columns over hot and cold spots on the water. These columns of air cause a horizontal breeze on the surfacethat radiates out ( or in) from a central point in 360 degrees . They look like puffs of breeze, except they don’t move across the water.

If you can somehow get the boat moving enough to get to one of these you can sail around the edges and use the energy of the ind to propel you towards the next vertical wind column. Never sail through the middle of the breeze; it will be on your bow. Always sail around the “side”, where the breeze direction is more on your beam.

the best explanation of this technique is in Frank Bethwaiteks books.

Other light wind tricksset two crew on the beam at the shrouds. Roll the boat from one side to the other smoothly, hangong onto the shroudto lean out, while the skipper sculls. On a small boat you can stand near the stern and pump up and down. But neither of these two tricks work on massive boats due to too much inertia.

In a light breeze , under 3 kts, put lots of twist in the sails to account for increased wind shear. Avoid any quick movements on the boat and in the trim of the sails. This keeps the laminar flow attached to the sail as much as possible. Also, because the flow over your sails is primarily laminar in under 3 kts, adjust the draft so the foil is comparatively shallow, entry is fine, and there are no sharp curves in the surface of the sail. Any big changes in direction on the Sails surface will interrupt laminar flow. Upwind, Be sure to match the twist of the Genoa to the Match the twist of the mainsail.

If you are sailing upwind in a puff and then the wind dies, don’t fall off in a attempt to keep the telltales flying as the apparent moves forward. Instead, steer up Right into the wind to get every boat length of upwind progress you canWhen the boat starts to slow down noticeably, fall off slowly/gently and ease the sails slowly and gently. (Racers call this situation a velocity header)

@jon hansen, do you have more to add to this? You know a lot about it.

JudyB
 
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RussC

.
Sep 11, 2015
1,519
Merit 22- Oregon lakes
Even In a “dead calm”, there often are some vertical up and down draft columns over hot and cold spots on the water. These columns of air cause a horizontal breeze on the surfacethat radiates out ( or in) from a central point in 360 degrees . They look like puffdps of breeze, except they don’t move across the water.

JudyB
aka thermals.
they can also sometimes randomly move across the water driven by any prevailing breeze. Thermals can sometimes be located by observing any raptors who happen to be in the area circling in them to maintain, or gain, altitude without expending energy/flapping their wings. ;)
 
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Jan 1, 2006
5,950
Slickcraft 26 Greenport, NY
I'm not expert in light air sailing since recreationally I'd start the engine and head to a place to swim. I'm not one of these stay out there until the flies feast on your in-animate flesh. Racing wise I've suffered my share but basically I think sailing is a dynamic sport. If you aren't moving you ain't sailing. But if you are in a no wind situation, and you think you have to stick it out, just get the boat moving. Don't worry about what direction. Once the boat is moving the foils start to work and maybe you can think of direction. As far as heel I think leeward heel does help. Sails flat as pancakes. Excessive heel isn't good since it creates drag. Some hull designs have less hull in the water while heeled. Sometimes sending the crew below to induce mild heel without as much heel as they would induce on the rail and keeping them in the middle of the boat is good boat trim. Beer helps. :beer:
 
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WayneH

.
Jan 22, 2008
854
Tartan 37 Pensacola Shipyard, FL
Ran across this one year in Santa Rosa Sound. We would pick up a breeze and get moving only to get headed a bit later. After hitting several of these headers, I looked back at the rest of the fleet and saw boats headed every which a way. None of us are really racers so we didn't figure it out quickly but the next couple of times we got a breeze, we just slacked the sheets when it died and managed to stay way ahead of the rest of the group.
 
Jun 25, 2004
1,108
Corsair F24 Mk1 003 San Francisco Bay, CA
aka thermals.
they can also sometimes randomly move across the water driven by any prevailing breeze. Thermals can sometimes be located by observing any raptors who happen to be in the area circling in them to maintain, or gain, altitude without expending energy/flapping their wings. ;)
By definition, thermals are localized up and down drafts caused by the uneven heating of the earth’s surface. They don’t move with the prevailing breeze. Thermals don’t come to you from across the water, like a prevailing breeze.

On a dead calm day, thermally induced down draftS hit the surface of the water it fans out horizontally thru 360 degrees. They look like stationary grey areas on the surface, usually very small in diameter, just a boat length or two, surrounded by a glassy calm water surface. The wind dissipates rapidly as it spreads out from the center, so they are usually very small in diameter.

If you steer to one side of the thermal, just off center, you can get some drive from the weak horizontal wind. Then you have to coast quietly and patiently towards the next column, using only momentum. You can, with planning ahead, coast from one tiny thermal to the next. ;)

Judy B
 

RussC

.
Sep 11, 2015
1,519
Merit 22- Oregon lakes
By definition, thermals are localized up and down drafts caused by the uneven heating of the earth’s surface. They don’t move with the prevailing breeze. Thermals don’t come to you from across the water, like a prevailing breeze.

On a dead calm day, thermally induced down draftS hit the surface of the water it fans out horizontally thru 360 degrees. They look like stationary grey areas on the surface, usually very small in diameter, just a boat length or two, surrounded by a glassy calm water surface. The wind dissipates rapidly as it spreads out from the center, so they are usually very small in diameter.

If you steer to one side of the thermal, just off center, you can get some drive from the weak horizontal wind. Then you have to coast quietly and patiently towards the next column, using only momentum. You can, with planning ahead, coast from one tiny thermal to the next. ;)

JudyB
@judy B
Great respect for your sailing knowledge and willingness to share that knowledge, but having flown gliders for 18 years and over 2000 hours of cross country flight time, thermals are one thing I do know a little bit about :).
by definition, thermals are updraft columns of air. there may be a downward aspect surrounding the column of rising air that reaches all the way to the surface, but rarely. and yes, thermals do almost always move with any prevailing breeze (albeit slowly, due to being "attached" to the surface). thermals are much more frequent on land, and certainly do occur over water, but it's still much easer to study them on land. so grab a beer and throw out your blanket to watch any raptors circling nearby. they aren't always straight columns of air, which requires that raptors constantly adjust the diameter and position of their circling, as well as constantly compensating for drift as the thermal travels downwind. watching the birds is by far the easiest way to know which way the prevailing wind is moving, as it drags the thermal along with it btw. isn't nature amazing! :)

also see:
 
Sep 22, 2018
1,869
Hunter 216 Kingston
I am more accustomed to the usage of “thermal” where the air mass over land heats up faster than that over the adjoining water. This occurs quite often in Kingston as it is at the end of Lake Ontario and I have experienced the same type of event at the confluence of the Squamish river and Howe Sound. Perhaps the type of wind I’m describing isn’t actually a “thermal” ???
 
Jun 25, 2004
1,108
Corsair F24 Mk1 003 San Francisco Bay, CA
@judy B
Great respect for your sailing knowledge and willingness to share that knowledge, but having flown gliders for 18 years and over 2000 hours of cross country flight time, thermals are one thing I do know a little bit about :).
by definition, thermals are updraft columns of air. there may be a downward aspect surrounding the column of rising air that reaches all the way to the surface, but rarely. and yes, thermals do almost always move with any prevailing breeze (albeit slowly, due to being "attached" to the surface). thermals are much more frequent on land, and certainly do occur over water, but it's still much easer to study them on land. so grab a beer and throw out your blanket to watch any raptors circling nearby. they aren't always straight columns of air, which requires that raptors constantly adjust the diameter and position of their circling, as well as constantly compensating for drift as the thermal travels downwind. watching the birds is by far the easiest way to know which way the prevailing wind is moving, as it drags the thermal along with it btw. isn't nature amazing! :)

also see:
I adopted your term “thermals” after you suggested it. Now, I think it’s not the right term for what I’m talking about. As a glider pilot, you know what you’re talking about.

what you called “ thermals” isn’t what I, talking about. Italking about something completely different. I retract my use of the term. It the wrong term to use, I guess.

What Im describing does not move with the prevailing breeze. These local cells are a localized phenomenon thatdoesn’t move across the surface of the water.

for a better description of the phenomenon, read Frank Bethwaite book Higher Performance Sailing. It’s described in great detail in one of the early chapters. I can’t find my copy of the book right now to give you a proper citation.

Judy
 
Feb 2, 2006
453
Hunter Legend 35 Kingston
I adopted your term “thermals” after you suggested it. Now, I think it’s not the right term for what I’m talking about. As a glider pilot, you know what you’re talking about.

what you called “ thermals” isn’t what I, talking about. Italking about something completely different. I retract my use of the term. It the wrong term to use, I guess.

What Im describing does not move with the prevailing breeze. These local cells are a localized phenomenon thatdoesn’t move across the surface of the water.

for a better description of the phenomenon, read Frank Bethwaite book Higher Performance Sailing. It’s described in great detail in one of the early chapters. I can’t find my copy of the book right now to give you a proper citation.

Judy
Frank Bethwaite is a pilot and a glider pilot too! very good book.
 

RussC

.
Sep 11, 2015
1,519
Merit 22- Oregon lakes
I am more accustomed to the usage of “thermal” where the air mass over land heats up faster than that over the adjoining water. This occurs quite often in Kingston as it is at the end of Lake Ontario and I have experienced the same type of event at the confluence of the Squamish river and Howe Sound. Perhaps the type of wind I’m describing isn’t actually a “thermal” ???
If the land adjoining the water has much slope to it, what you're experiencing may be anabatic or katabatic winds. doesn't sound like the definition of thermal activity.

 
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RussC

.
Sep 11, 2015
1,519
Merit 22- Oregon lakes
Frank Bethwaite is a pilot and a glider pilot too! very good book.
I'll have to check that out. I'm always interested to learn new things.

PS:
ouch!! on second thought.... maybe I'll wait for the movie. I may not be smart enough to read it for $65.00 in paperback. :yikes:
 
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Jun 25, 2004
1,108
Corsair F24 Mk1 003 San Francisco Bay, CA
I found an older edition of Frank Bethwaite's book, High Performance Sailing, . Here is one page from Chapter 4 "Light Airs".

Bethwaite uses the terms cells, cores, and curtains of air. He concerns himself primarily with winds at the surface, as it pertains to trimming and helming.


IMG_1210.jpg
 
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Jun 25, 2004
1,108
Corsair F24 Mk1 003 San Francisco Bay, CA
PS:
ouch!! on second thought.... maybe I'll wait for the movie. I may not be smart enough to read it for $65.00 in paperback. :yikes:
It's $35 on Amazon. Worth every penny, whether you sail a heavy displacement keel boat or an apparent wind screamer (multihull) or something in between.

 
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May 25, 2012
3,785
john alden caravelle 42 sturgeon bay, wis
if you want to sail these toys to their full potential you need to be a student of Frank. understanding how the air moves across the surface of the earth is very important.
understanding how to tune your sails is important, and knowing the science for doing such.
understanding the wind, and the science behind it.
then the science of the interplay between the two.
if you want to know what the rockstars of sailing know, study franks teachings.
then you can teach your crew such to all be using the same recipe, if you will.
i have three copies. one on the boat. one in each of my houses.
half of the entire book is about the weather. something all sailors should know.

there are only two types of wind, do you know them? and how they interplay. read frank's teachings.
 

RussC

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Sep 11, 2015
1,519
Merit 22- Oregon lakes
@JudyB

I'll have to read that page a few dozen times to fully absorb it :oops:. I've become so accustomed to "seeing" thermal and other weather activity at altitude rather than ground/water level, so obviously there is lots to be learned about how this low level activity works.thanks for stirring my kettle of brain cells ;)

I think the Higher performance sailing is what I was seeing at $65.00 and the High performance sailing is at $35. maybe I'm smart enough for the plain High performance version :laugh:.
 
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Sep 22, 2018
1,869
Hunter 216 Kingston
If the land adjoining the water has much slope to it, what you're experiencing may be anabatic or katabatic winds. doesn't sound like the definition of thermal activity.

Not much elevation difference in Kingston land - water so I’m not sure anabatic or katabatic applies. Squamish is a different thing as the river drains from the snowpack on Whistler.

Although Kingston is usually “windy” the “thermal” as it’s known locally happens more often in the heat of the summer.

Fairly calm in early morning, wind kicks in around 10am builds through the early pm, peaks later in afternoon and then starts to drop off around 6pm. Happens most often on hot sunny days - hence the theory that I expressed above.