Jib Angles - Do I Have This Right?

Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
Jackdaw, I think I've read where you have said that these smaller head sails should be able to sheet in at max 8 Deg.
As SG also notes, the optimal number bumps moves around for each boat, based on boat hull and rig design. Generally, boats with better foils do tighter angles. This means long narrow keels, an also high aspect JIBS. High aspect in headsails normally means above 3.5:1. So if your 'J' is 9.6 feet, your 'P' would need to be 32 feet to be considered High Aspect.

As a point of reference, the headsail sheeting angle on TP52 is 4-5 degrees. And they sail with their mainsheet travels cranked at the way to windward.

As a rule, make it wider than narrower. A wider angle will be forgiving and fast over the water. Too tight and you end up with a slow boat that stalls easily upwind.
 
  • Like
Likes: topcat0399
Aug 22, 2011
1,113
MacGregor Venture V224 Cheeseland
If your fairleads are too far back, the foot will be tight and the leach will bow out too much and flutter. It could even twist off at the top too much. You won't get good camber across the foil and you'll have poor laminar flow. I can see how that might cause "pounding".
If your fairleads are too far forward, the foot will be too loose and the leach will look better, but there will be too much camber causing over powering and poor angle of attack. She will heel to much, gain a bit of lee helm and lose pointing degrees. You might even get a feeling of "pumping" as she catches then spills air on a close reach while pitching in seas. In both cases it will look like you can't pull the sheet right enough.

-Will (Dragonfly)
I do believe you are right on.
What you describe is exactly what I experienced.
 
Aug 22, 2011
1,113
MacGregor Venture V224 Cheeseland
As SG also notes, the optimal number bumps moves around for each boat, based on boat hull and rig design. Generally, boats with better foils do tighter angles. This means long narrow keels, an also high aspect JIBS. High aspect in headsails normally means above 3.5:1. So if your 'J' is 9.6 feet, your 'P' would need to be 32 feet to be considered High Aspect.

As a point of reference, the headsail sheeting angle on TP52 is 4-5 degrees. And they sail with their mainsheet travels cranked at the way to windward.

As a rule, make it wider than narrower. A wider angle will be forgiving and fast over the water. Too tight and you end up with a slow boat that stalls easily upwind.
Makes perfect sense.
My hull certainly isn't performance, my sails certainly aren't high aspect,
and my keel certainly isn't long and narrow!
My rudder is a nice foil now since I redid it to NACA 12 anyway.
At last something going my way!
:yikes:
 
  • Like
Likes: Jackdaw
Jan 11, 2014
11,321
Sabre 362 113 Fair Haven, NY
I need my headsails to set well in 30 mph hard on the wind.
Where are you sailing that finds you in 30 mph headwinds?

In general, I think it is best to rig the boat to sail well in the typical conditions for your area. In an area with lots of light air, bigger lighter sails with lighter sheets and rigging. In regions with heavier air smaller heavier sails with larger sheets and rigging.

Sailing a boat that is rigged for 20+ mph winds is not much fun when the wind is down in the low teens or single digits. Likewise sailing a lightly rigged boat in 20+ mph wind is kind of scary and potentially damaging to the boat.
 
Aug 22, 2011
1,113
MacGregor Venture V224 Cheeseland
Where are you sailing that finds you in 30 mph headwinds?

In general, I think it is best to rig the boat to sail well in the typical conditions for your area. In an area with lots of light air, bigger lighter sails with lighter sheets and rigging. In regions with heavier air smaller heavier sails with larger sheets and rigging.

Sailing a boat that is rigged for 20+ mph winds is not much fun when the wind is down in the low teens or single digits. Likewise sailing a lightly rigged boat in 20+ mph wind is kind of scary and potentially damaging to the boat.

Scary - FUN I hope you mean.

Before I got the new mainsail and all of the proper controls for it there was nothing more thrilling than spending the entire 20+ wind days out washing the port-lights. With the new main that doesn't occur very often anymore. Kind of miss the boat not being so squirrelly somehow. It was a blast wrestling her. When I see the others boats heading in I'm smiling. Fun ahead.

Lake Petenwell is the 2nd largest lake in WI and it can get damn windy. Yes in the lulls, I'm dull dull dull.
Maybe the new Asym will change that a little?

Anyway I'm rigging for wherever I end up, probably not here. Gulf of Mexico, who knows where else. When its time I'm going in this boat. I have rebuilt this boat way stronger than it was built so I don't worry too much. If it breaks - I'll fix it. I carry a supply of line and spare gear, tools, materials, etc..

Just got to sort out this headsail thing with something I will be pleased with.
 
Jan 11, 2014
11,321
Sabre 362 113 Fair Haven, NY
Scary - FUN I hope you mean.

Before I got the new mainsail and all of the proper controls for it there was nothing more thrilling than spending the entire 20+ wind days out washing the port-lights. With the new main that doesn't occur very often anymore. Kind of miss the boat not being so squirrelly somehow. It was a blast wrestling her. When I see the others boats heading in I'm smiling. Fun ahead.

Lake Petenwell is the 2nd largest lake in WI and it can get damn windy. Yes in the lulls, I'm dull dull dull.
Maybe the new Asym will change that a little?

Anyway I'm rigging for wherever I end up, probably not here. Gulf of Mexico, who knows where else. When its time I'm going in this boat. I have rebuilt this boat way stronger than it was built so I don't worry too much. If it breaks - I'll fix it. I carry a supply of line and spare gear, tools, materials, etc..

Just got to sort out this headsail thing with something I will be pleased with.
There is a world of difference between sailing in a 30 mph breeze on a small shallow inland lake and sailing in the same breeze on the ocean or the Great Lakes. The difference is the fetch and the size of the waves.

On eastern Lake Ontario (where I sail) when the wind is a sustained 20+ knots from the west or NW the waves will build to 8+ feet, by the time the wind is at 30+ knots (~35 mph) the waves have built to 10 to 12 feet. I got caught once in a 40+knot breeze as a front blew through. The forecast was for 20-25 knots. The seas built to 12+ feet with some waves in the 14+ foot range. This in a Tanzer 22, a substantially heavier boat than a Venture 224.

We were sailing downwind and surfing the waves at 10+ Knots. At one point the bow of the boat came out of the water past the knot meter impeller. In these conditions, broaching, pitchpoling, or an accidental crash gybe were possibilities. It would have been nearly impossible to go to weather. Once in the trough of the wave the mainsail would have been blanketed by the wave and there would be no power to sail up over the wave. Even downwind our boat speed would drop from 10+ (the knot meter was pegged) to 3 or 4 knots in the troughs until the next wave lifted the boat and put it back into the wind.

If you do take this boat to big waters, it is important to be able to reduce sail to be safe if you get caught out in bad weather, however, the wind conditions that are fun on Lake Petenwell can be very dangerous on big water.

The photo below shows a wave hitting the break wall at Oswego, NY. the wind was in the 30 knot range for a few hours before this photo was shot. The tower is 57' above the average lake level.

lighthousewave.jpg
 
  • Like
Likes: Will Gilmore
Aug 22, 2011
1,113
MacGregor Venture V224 Cheeseland
There is a world of difference between sailing in a 30 mph breeze on a small shallow inland lake and sailing in the same breeze on the ocean or the Great Lakes. The difference is the fetch and the size of the waves.

On eastern Lake Ontario (where I sail) when the wind is a sustained 20+ knots from the west or NW the waves will build to 8+ feet, by the time the wind is at 30+ knots (~35 mph) the waves have built to 10 to 12 feet. I got caught once in a 40+knot breeze as a front blew through. The forecast was for 20-25 knots. The seas built to 12+ feet with some waves in the 14+ foot range. This in a Tanzer 22, a substantially heavier boat than a Venture 224.

We were sailing downwind and surfing the waves at 10+ Knots. At one point the bow of the boat came out of the water past the knot meter impeller. In these conditions, broaching, pitchpoling, or an accidental crash gybe were possibilities. It would have been nearly impossible to go to weather. Once in the trough of the wave the mainsail would have been blanketed by the wave and there would be no power to sail up over the wave. Even downwind our boat speed would drop from 10+ (the knot meter was pegged) to 3 or 4 knots in the troughs until the next wave lifted the boat and put it back into the wind.

If you do take this boat to big waters, it is important to be able to reduce sail to be safe if you get caught out in bad weather, however, the wind conditions that are fun on Lake Petenwell can be very dangerous on big water.

The photo below shows a wave hitting the break wall at Oswego, NY. the wind was in the 30 knot range for a few hours before this photo was shot. The tower is 57' above the average lake level.

View attachment 163746
That's quite a tale and I'm glad you came through it ok so you are here to be able to give others like me the benefit of your experience.

I fully get that inland lakes are not the same as oceans. But there is still value I think in navigating rough weather on lakes in preparation for bigger waters. Even Lake Petenwell occasionally sees 10 foot waves and I have been out in 8 footers there.

My new main has 2 reefs and I am considering adding a third. I have my eye on a couple of even smaller head sails for storm use.

But I also know that history has shown that many people have done far more with far less and I have faith in myself and my little boat.

On to the future!
 
  • Like
Likes: Will Gilmore
Sep 20, 2014
1,320
Rob Legg RL24 Chain O'Lakes
Just one more thing to point out, Look were your stays are. On my boat, the stays highly limit the position of the attachment point. I have tracks, but the last section of track is unusable.
 
  • Like
Likes: Will Gilmore
Aug 22, 2011
1,113
MacGregor Venture V224 Cheeseland
Just one more thing to point out, Look were your stays are. On my boat, the stays highly limit the position of the attachment point. I have tracks, but the last section of track is unusable.

Indeed. That's one of the compromises that I'm trying to work out. My new 120 Genny hits the shrouds upwind and I do not like it.
I wish the sail maker would have steered me to a 115 instead. Alas, live and learn. The hazards of mail order I guess.
 
Oct 19, 2017
7,732
O'Day 19 Littleton, NH
Indeed. That's one of the compromises that I'm trying to work out. My new 120 Genny hits the shrouds upwind and I do not like it.
I wish the sail maker would have steered me to a 115 instead. Alas, live and learn. The hazards of mail order I guess.
Try running your Genny sheet inside and use a whisker pole for broad reaching and downwind tacks. If your genny clew is cut as low as your other headsails, maybe the fairleads are too far aft.
Another thought is to have a second set of sheets to use for the inside trim when close reaching. Maybe these aren't practical solutions, but with your chainplates 2' aft of your mast and fully outboard, you may have room to sheet to the inside.

-Will (Dragonfly)
 
  • Like
Likes: topcat0399
Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
Indeed. That's one of the compromises that I'm trying to work out. My new 120 Genny hits the shrouds upwind and I do not like it.
I wish the sail maker would have steered me to a 115 instead. Alas, live and learn. The hazards of mail order I guess.
Ah. I forgot, your boat has shrouds that go up from chainplate at the hull/deck joint. These days we call that a 'non-overlapper', meaning that the boat was design to fly headsails that do not overlap with the rigging. As you know, the clew might go past the mast, but the real limiting factor is where the leach might come in contact with the lower diagonal (D1) shroud or the spreader. Depending on the cut, the max sail size is normally somewhere between 105 and 110 LP%.

Attempts to trim a sail AROUND the rig will usually end in disappointment or damage, in particular when trying to go upwind. And as that was the basis of this entire thread....... ;^)

Boats of this type need a spinnaker when sailing with the wind aft of the beam.
 
Aug 22, 2011
1,113
MacGregor Venture V224 Cheeseland
Try running your Genny sheet inside and use a whisker pole for broad reaching and downwind tacks. If your genny clew is cut as low as your other headsails, maybe the fairleads are too far aft.
Another thought is to have a second set of sheets to use for the inside trim when close reaching. Maybe these aren't practical solutions, but with your chainplates 2' aft of your mast and fully outboard, you may have room to sheet to the inside.

-Will (Dragonfly)

I will definitely give all of those suggestions a good try.

Thanks Will.
 
Oct 19, 2017
7,732
O'Day 19 Littleton, NH
I will definitely give all of those suggestions a good try.

Thanks Will.
Pay attention to Jackdaw's point about spreader interference. A 120 with your swept spreaders may or may not work. You don't want to tear your sail or break a spreader. It will depend on how your Genny is cut and where your spreaders are.
Good luck. This kind of experimentation is part of what makes sailing so exciting.

-Will (Dragonfly)
 
  • Like
Likes: topcat0399
Aug 22, 2011
1,113
MacGregor Venture V224 Cheeseland
Ah. I forgot, your boat has shrouds that go up from chainplate at the hull/deck joint. These days we call that a 'non-overlapper', meaning that the boat was design to fly headsails that do not overlap with the rigging. As you know, the clew might go past the mast, but the real limiting factor is where the leach might come in contact with the lower diagonal (D1) shroud or the spreader. Depending on the cut, the max sail size is normally somewhere between 105 and 110 LP%.

Attempts to trim a sail AROUND the rig will usually end in disappointment or damage, in particular when trying to go upwind. And as that was the basis of this entire thread....... ;^)

Boats of this type need a spinnaker when sailing with the wind aft of the beam.

I am learning so much about headsails lately.

Is a new 120% worth cutting down?

I have discovered through measurements that
my new 90 Jib is actually an 80
my new 100% is actually a 90
I think that's because of the cut of the clew.

That I may end up running a 6 foot track on each side deck
after all because of the range of headsails.
Of course the side decks are cored complicating installation of track.

Decisions decisions....
 
Jan 11, 2014
11,321
Sabre 362 113 Fair Haven, NY
I am learning so much about headsails lately.

Is a new 120% worth cutting down?

I have discovered through measurements that
my new 90 Jib is actually an 80
my new 100% is actually a 90
I think that's because of the cut of the clew.

That I may end up running a 6 foot track on each side deck
after all because of the range of headsails.
Of course the side decks are cored complicating installation of track.

Decisions decisions....
Are you measuring the sail size based on the J measurement or the percent of the foretriangle area?
 
Jan 11, 2014
11,321
Sabre 362 113 Fair Haven, NY
Measured J= 108"
Measured LP= 98"

98/108= 0.907 90%

Is this incorrect?
Yep that's right.

I see little advantage to cutting down the 120%. While it may not work well going to weather, off the wind, i.e., on a beam or broad reach the extra sail area will help. Making it a 100% really won't do much, the difference in performance between a 90% and 100% will be trivial in most wind conditions.
 
Aug 22, 2011
1,113
MacGregor Venture V224 Cheeseland
Yep that's right.

I see little advantage to cutting down the 120%. While it may not work well going to weather, off the wind, i.e., on a beam or broad reach the extra sail area will help. Making it a 100% really won't do much, the difference in performance between a 90% and 100% will be trivial in most wind conditions.

(sigh)

That's what I figured.

So in your opinion, if I end up installing tracks should I put them as far as I can out board or as far as I can inboard?
I think I would rather in-haul than out-haul if it came to be necessary.
I don't have any experience with this to go on.
 
Oct 19, 2017
7,732
O'Day 19 Littleton, NH
I think I would rather in-haul than out-haul if it came to be necessary
I think the same way. I also think an inhaul line has to be stepped over when working the deck, but maybe not so with an outhaul line. If you are not racing, you can let the wind be the outhaul and live with a slightly less desirable shape. Naw! Go with the inhaul or outhaul. Compromising on sail shape here means losing Ponting degrees while adding more heel and possibly a lee helm.

-Will (Dragonfly)
 
Jan 11, 2014
11,321
Sabre 362 113 Fair Haven, NY
(sigh)

That's what I figured.

So in your opinion, if I end up installing tracks should I put them as far as I can out board or as far as I can inboard?
I think I would rather in-haul than out-haul if it came to be necessary.
I don't have any experience with this to go on.
Well, there is a third option that may be workable and that is to install 2 tracks on each side. One track outboard and aft for larger head sails and a shorter inboard track that set forward for smaller headsails. This links to a photo of a Tanzer 22. Notice the jib track on the cabin top that is used for the 110% and a track on the rail for use with larger sails, a 170% and a 145%.

http://baybreezeyachtsales.com/wp-content/uploads/2016/08/Starboard_Bow-1.jpg

On the Tanzer, the 145% is pretty useless as a tight sheeting angle can't be achieved. The clew comes to the widest part of the boat. A 170% with a longer foot will allow for a closer sheeting angle.
 
  • Like
Likes: Will Gilmore