Lazy Jacks on a racing mainsail

[Strimar]

Has anyone come up with a simple lazy jack setup for a 30-35' sailboat with a 13' boom that does not compromise racing performance and is stowed out of the way when sailing/racing?

 

[Mid]

does not compromise racing performance and is stowed out of the way when sailing/racing?

yep , strip it and leave it ashore .

 

[yoyo]

As mid said - but if you must have them...
Thin dyneema with small ronstan skock blocks. When sailing, loosen them, gather and pull them forward to front of boom around the reefing hooks/carabiner/soft shackle or similar and tension everything. You end up with dyneema tight along boom and up/down back of mast. Deploy prior to dropping sail. You can also tuck them away when mainsail cover is installed without needing to modify cover. Depending on how you plan to cleat/tension the lazy jack tails you probably want a cover on that area of the dyneema.

 

[slug zitski]

Has anyone come up with a simple lazy jack setup for a 30-35' sailboat with a 13' boom that does not compromise racing performance and is stowed out of the way when sailing/racing?

Internal lazy jacks are the best solution for a racer cruiser

Be carefull with lazy jack mainsail chafe at the boom ... fabric helps

Google class 40 boats pics for ideas or talk to s sailmaker

 

[DDW]

Just let them hang out. 3 mm dyneema lazyjacks will make your competitors think you aren't serious, allowing you to sneak by them, while not compromising performance an amount you can measure except perhaps at the Olympic class boat level.

 

[steele]

As mid said - but if you must have them...
Thin dyneema with small ronstan skock blocks. When sailing, loosen them, gather and pull them forward to front of boom around the reefing hooks/carabiner/soft shackle or similar and tension everything. You end up with dyneema tight along boom and up/down back of mast. Deploy prior to dropping sail. You can also tuck them away when mainsail cover is installed without needing to modify cover. Depending on how you plan to cleat/tension the lazy jack tails you probably want a cover on that area of the dyneema.

This is what I use on my 35' racer/cruiser. I don't need the blocks, SS eyes on the dynema work fine. They are tensioned on small horn cleats on the mast with no covers on the line and no evidence of wear over 10 years. As long as the main is flaked well I don't deploy them leaving the dock or raising the sail, just when lowering.

Performance wise I would have to be a much better sailor to notice the penalty of lazyjacks. An acquaintance who is a very good sailor has done some research and he thinks we underestimate the drag of halyards and other lines perpendicular to the wind. Perhaps someone smarter than me can figure out the wind load of a 1/8" column of line tucked against the mast.

 

[Fleetwood]

As mid said - but if you must have them...
Thin dyneema with small ronstan skock blocks. When sailing, loosen them, gather and pull them forward to front of boom around the reefing hooks/carabiner/soft shackle or similar and tension everything. You end up with dyneema tight along boom and up/down back of mast. Deploy prior to dropping sail. You can also tuck them away when mainsail cover is installed without needing to modify cover. Depending on how you plan to cleat/tension the lazy jack tails you probably want a cover on that area of the dyneema.

Same

 

[PaulK]

As mid said - but if you must have them...
Thin dyneema with small ronstan skock blocks. When sailing, loosen them, gather and pull them forward to front of boom around the reefing hooks/carabiner/soft shackle or similar and tension everything. You end up with dyneema tight along boom and up/down back of mast. Deploy prior to dropping sail. You can also tuck them away when mainsail cover is installed without needing to modify cover. Depending on how you plan to cleat/tension the lazy jack tails you probably want a cover on that area of the dyneema.

This is what we do.^^^^^^^

 

[Strimar]

This is what we do.^^^^^^^ View attachment 572831

Topping lift to help hold the leech in check or am I missing something?

 

[mathystuff]

Performance wise I would have to be a much better sailor to notice the penalty of lazyjacks. An acquaintance who is a very good sailor has done some research and he thinks we underestimate the drag of halyards and other lines perpendicular to the wind. Perhaps someone smarter than me can figure out the wind load of a 1/8" column of line tucked against the mast.

I'm to lazy to do the math, but the Cd of a circle is .47, which is way higher than a streamlined section. All the lines going up a mast on the outside are a significant amount of drag.

Does that mean your average sailor is going to note the added drag from lazyjacks? Probably not. But small improvements do add up.

 

[PaulK]

Topping lift to help hold the leech in check or am I missing something?

We're removing the topping lift for next season. It only chafes the sail and on occasion gets wrapped around the backstay. Since it's fixed at the top it's useless as a reserve main halyard or as a safety line for the bosun's chair. The rigid vang works fine to hold the boom up.

 

[DDW]

17 knots of wind is 1 psf dynamic pressure. A circular section has a varying Cd, depending on the critical Re, as much as 0.7, as little as 0.3. Something that small probably 0.7 as the Re will be low. On a 35' boat maybe you have 60' of line. So 60 x .125 / 12 * 1 * 0.7 = 0.44 lbs of drag @ 17 knots. Not nothing but not measurable on a boat even with very expensive equipment. The rig on a 35' boat has something like 175 lbs of aerodynamic drag. Would it actually be less if pulled against the mast? Maybe, but not nothing, either. If you are going for style points, then send then down or pull then against the mast. If you care only about speed, there are about 100 other things to pay attention to first.

 

[Raz'r]

We use the reefing lines as a doubly duty lazyjack system. Drop sail a bit, snug the reefing line, do it again, now you’re dealing with only about 1/2 of the sail flopping around.

 

[Haligonian Winterr]

As mid said - but if you must have them...
Thin dyneema with small ronstan skock blocks. When sailing, loosen them, gather and pull them forward to front of boom around the reefing hooks/carabiner/soft shackle or similar and tension everything. You end up with dyneema tight along boom and up/down back of mast. Deploy prior to dropping sail. You can also tuck them away when mainsail cover is installed without needing to modify cover. Depending on how you plan to cleat/tension the lazy jack tails you probably want a cover on that area of the dyneema.

Also don't need the blocks/rings/thimbles on portions of the dyneema that don't move much. Ex. top of a bridle. Will reduce things that tap against mast/boom and annoy the shit out of you at night.

 

[Zonker]

I'm to lazy to do the math, but the Cd of a circle is .47,

Usually a cylinder is ~ 1.0 in air speeds we are considering

So 3mm rope x say 12m?

Cd = 1.0
Area = 0.003m x 12m = 0.036 m2
density air = 1.204 kg/m3
V = say upwind, 12 knots = about 6 m/s

Drag = 1/2 Cd A density V^2 = 1.0 x 0.036m2 x 1.204 kg/m3 x (6 m/s)^2 = ~0.78 N

If you have 2 of them that long + a few more short sections of rope, with blocks, and associated intersection drag etc - you're in the ballpark of 3N

Or roughly 0.1% of the resistance of a 30' sailboat sailing at 5 or 6 knots.

Loose clothing on the crew on the rail probably is worse. More lycra!

 

[Mid]

Does that mean your average sailor is going to note the added drag from lazyjacks?

not to mention the fok up when you snag the fokers .

 

[El Borracho]

It is not so much the drag of the lazy jacks themselves. It is the philosophy they boldly reveal. Those lazy jacks plus the fifty other details excused with the same rationale certainly makes a noticeable difference in sailing speed.

Rather pointless they are, anyway, unless dropping the mainsail has a long history of spilling the cocktails.

 

[dacapo]

Usually a cylinder is ~ 1.0 in air speeds we are considering

So 3mm rope x say 12m?

Cd = 1.0
Area = 0.003m x 12m = 0.036 m2
density air = 1.204 kg/m3
V = say upwind, 12 knots = about 6 m/s

Drag = 1/2 Cd A density V^2 = 1.0 x 0.036m2 x 1.204 kg/m3 x (6 m/s)^2 = ~0.78 N

If you have 2 of them that long + a few more short sections of rope, with blocks, and associated intersection drag etc - you're in the ballpark of 3N

Or roughly 0.1% of the resistance of a 30' sailboat sailing at 5 or 6 knots.

Loose clothing on the crew on the rail probably is worse. More lycra!

too many numbers. my head hertz

 

[Tylo]

This is what we do.^^^^^^^ View attachment 572831

That is one sexy set of sails (the main in particular). Nice!

 

[Strimar]

This is what I use on my 35' racer/cruiser. I don't need the blocks, SS eyes on the dynema work fine. They are tensioned on small horn cleats on the mast with no covers on the line and no evidence of wear over 10 years. As long as the main is flaked well I don't deploy them leaving the dock or raising the sail, just when lowering.

Performance wise I would have to be a much better sailor to notice the penalty of lazyjacks. An acquaintance who is a very good sailor has done some research and he thinks we underestimate the drag of halyards and other lines perpendicular to the wind. Perhaps someone smarter than me can figure out the wind load of a 1/8" column of line tucked against the mast.

ss eyes do you mean thimbles and do you have a picture or diagram of the setup?