Catamaran tacking angles , really that bad???

[Uncle Bob]

Originally Posted by Jim Cate

^^^^

Upwind with a gennaker? That's kinda unusual...

Jim

[arsenelupiga]

Originally Posted by Uncle Bob

yup, it is true. some people have different naming but lets call it super large jib.

there are 2 ways to implement upwind. one way is outremer where boats are build narrow so one can use it outside shrouds and still achieve good upwind angles.

The other is wide cat, like Lagoon 400 and one sails upwind inside shrouds. I have data point where L 400 achieved 4.5 kn VMG in 11 kn true with this setup.

[arsenelupiga]

Originally Posted by Jim Cate

^^^^

Upwind with a gennaker? That's kinda unusual...

Jim

just for you, found this video, just enjoyable :

https://youtu.be/VRRXoajZnA8

6 kn in 6 kn wind.

On L 400 looks pretty similar except sails goes inside shrouds for anything below 45 app.

[Jim Cate]

Originally Posted by arsenelupiga

just for you, found this video, just enjoyable :

https://youtu.be/VRRXoajZnA8

6 kn in 6 kn wind.

On L 400 looks pretty similar except sails goes inside shrouds for anything below 45 app.

Nice pleasant sailing for sure, but where does it say that it was going to windward or what the wind angle was or how fast they were going. I didn't find that in the clip.

And that sail appeared to me to be a code 0 type rather than a gennaker...

so I'm still a bit confused as to what you are claiming.

Jim

[arsenelupiga]

Originally Posted by Jim Cate

Nice pleasant sailing for sure, but where does it say that it was going to windward or what the wind angle was or how fast they were going. I didn't find that in the clip.

And that sail appeared to me to be a code 0 type rather than a gennaker...

so I'm still a bit confused as to what you are claiming.

Jim

that is the type of sail i am using - just an example. sailmaker said it is screecher, i am aware there is naming confusion with code 0. As the sail was designed for reaching, upwind we can only achieve 5 kn at 34 app in 10 kn true. In my opinion wasted of my budget to use laminate material as dracon should suffice for up to 50 app.

I am testing for sail amendment so my next laminate sail will be capable hopefully 6 kn at 30 in 10 kn true and still keep good/better reaching potential.

[Uncle Bob]

Originally Posted by arsenelupiga

that is the type of sail i am using - just an example. sailmaker said it is screecher, i am aware there is naming confusion with code 0. As the sail was designed for reaching, upwind we can only achieve 5 kn at 34 app in 10 kn true. In my opinion wasted of my budget to use laminate material as dracon should suffice for up to 50 app.

I am testing for sail amendment so my next laminate sail will be capable hopefully 6 kn at 30 in 10 kn true and still keep good/better reaching potential.

Ah, so it's not a gennaker at all.

[arsenelupiga]

Originally Posted by Uncle Bob

Ah, so it's not a gennaker at all.

Ha, i always knew my english sucks now i have proof. Gennaker, screecher, code 0 - all the same for me. One day will have to open sailing wiki and learn differences.

[Uncle Bob]

Originally Posted by arsenelupiga

Ha, i always knew my english sucks now i have proof. Gennaker, screecher, code 0 - all the same for me. One day will have to open sailing wiki and learn differences.

Different cuts, mounts, uses therefore different sails.

[Jim Cate]

Originally Posted by Uncle Bob

Different cuts, mounts, uses therefore different sails.

I reckon that it is a matter of control of the luff of free flying sails. Consider how important a tight forestay is to good upwind performance in monohull boats, and then think about trying to get the same sail shape with an unsupported luff sail.

Perhaps it can be done... we keep seeing old limits exceeded, but for true upwind (as in really hard on the wind) a free luff sail seems handicapped.

Jim

[arsenelupiga]

Originally Posted by Jim Cate

I reckon that it is a matter of control of the luff of free flying sails. Consider how important a tight forestay is to good upwind performance in monohull boats, and then think about trying to get the same sail shape with an unsupported luff sail.

Perhaps it can be done... we keep seeing old limits exceeded, but for true upwind (as in really hard on the wind) a free luff sail seems handicapped.

Jim

yeah, that is exactly what I am testing. free luff, presume you mean sail torsion rope has to be really tensioned to get it working properly. And note that this setup is good for up to 15 kn app. then use jib. I can achieve 3.2 kn VMG direct upwind with this sail in 10 kn true. That is hard-on upwind sailing for my boat. With jib can do in same condition 3 kn vmg. Not that exciting improvement especially as these conditions are really rare in cruising life.

[Uncle Bob]

Originally Posted by arsenelupiga

yeah, that is exactly what I am testing. free luff, presume you mean sail torsion rope has to be really tensioned to get it working properly. And note that this setup is good for up to 15 kn app. then use jib. I can achieve 3.2 kn VMG direct upwind with this sail in 10 kn true. That is hard-on upwind sailing for my boat. With jib can do in same condition 3 kn vmg. Not that exciting improvement especially as these conditions are really rare in cruising life.

I would have described a free luff as a sail that is anchored at the tack and head, not one that has a torsion rope on a furler, but then perhaps I am mistaken, it has been known to happen.

[fxykty]

Names are funny, but most come from racing.

Gennaker is generally useful for any cruising cat to fill the gap between genoa and spinnaker (hence the name!!) for close to beam reaching in lighter winds. It is basically equivalent to a racing (monohull) Code 0. As the code numbers increase the sail becomes fuller.

Screecher is a specialised cat sail for lighter wind upwind, generally used by cats with self tacking jibs to fill the hole upwind. It is basically equivalent to a racing (monohull) J0. It is a straight luffed upwind sail that is flown in front of the main structural forestay from a bow pole.

Both sails are flown with a bottom up furler with torsion rope to provide a tight luff. Membrane sails are now being developed that have their own structured luff and don’t need a separate torsion rope. This is lighter weight and requires less halyard tension - 2:1 halyard not needed.

Our cat came with a 120sqm gennaker that sets from our 1.4m bow pole and hoists to the 7/8 hounds just above the forestay. For comparison, our self tacking jib is 35sqm. The gennaker must be set outside the cap shrouds as the clew is within 1.5m of the stern quarter block when fully sheeted in and the leech is too full. It is triradial cut Dacron - bloody heavy and about 30cm in diameter in the centre of the furl. It is on a furler with a torsion rope luff rope. The halyard is 2:1 Dyneema cored and is tensioned to about 3 ton luff tension.

We can sail up to 40 AWA in anything from 3-10 knots TWS (our boat manual says maximum 15 knots AWS). Our boat speed is 100-120% of TWS in this wind speed range. But note that the 40 AWA works out to near 90 TWA. The gennaker is definitely not for upwind work. But it is a lovely, albeit heavy, sail to keep moving in lighter winds.

The gennaker works down to 90 AWA in lighter winds and down to 150 AWA in stronger winds. But generally above 12-15 knots AWS our jib is nearly as fast and with a lot less pressure on the rig and boat.

Our next sail will be a screecher. It will be cut with a hollow leech to fit inside the cap shrouds and sheeted from the aft end of the cabin top. It will be about 75sqm (sister ships that have genoas instead of self tacking jibs have 50sqm genoas). We will make it from Dyneema membrane for shape and weight. It will also be furled and with a structural luff we can use less halyard tension.

This sail will keep us to about 80% of TWS and provide a TWA of 50-55 degrees - a decent VMG of 50% TWS so we can sail faster upwind in light winds under 10 knots than with our jib.

[Happ]

Originally Posted by fxykty

Names are funny, but most come from racing.

Gennaker is generally useful for any cruising cat to fill the gap between genoa and spinnaker (hence the name!!) for close to beam reaching in lighter winds. It is basically equivalent to a racing (monohull) Code 0. As the code numbers increase the sail becomes fuller.

Screecher is a specialised cat sail for lighter wind upwind, generally used by cats with self tacking jibs to fill the hole upwind. It is basically equivalent to a racing (monohull) J0. It is a straight luffed upwind sail that is flown in front of the main structural forestay from a bow pole.

Both sails are flown with a bottom up furler with torsion rope to provide a tight luff. Membrane sails are now being developed that have their own structured luff and don’t need a separate torsion rope. This is lighter weight and requires less halyard tension - 2:1 halyard not needed.

Our cat came with a 120sqm gennaker that sets from our 1.4m bow pole and hoists to the 7/8 hounds just above the forestay. For comparison, our self tacking jib is 35sqm. The gennaker must be set outside the cap shrouds as the clew is within 1.5m of the stern quarter block when fully sheeted in and the leech is too full. It is triradial cut Dacron - bloody heavy and about 30cm in diameter in the centre of the furl. It is on a furler with a torsion rope luff rope. The halyard is 2:1 Dyneema cored and is tensioned to about 3 ton luff tension.

We can sail up to 40 AWA in anything from 3-10 knots TWS (our boat manual says maximum 15 knots AWS). Our boat speed is 100-120% of TWS in this wind speed range. But note that the 40 AWA works out to near 90 TWA. The gennaker is definitely not for upwind work. But it is a lovely, albeit heavy, sail to keep moving in lighter winds.

The gennaker works down to 90 AWA in lighter winds and down to 150 AWA in stronger winds. But generally above 12-15 knots AWS our jib is nearly as fast and with a lot less pressure on the rig and boat.

Our next sail will be a screecher. It will be cut with a hollow leech to fit inside the cap shrouds and sheeted from the aft end of the cabin top. It will be about 75sqm (sister ships that have genoas instead of self tacking jibs have 50sqm genoas). We will make it from Dyneema membrane for shape and weight. It will also be furled and with a structural luff we can use less halyard tension.

This sail will keep us to about 80% of TWS and provide a TWA of 50-55 degrees - a decent VMG of 50% TWS so we can sail faster upwind in light winds under 10 knots than with our jib.

O had the same sail on my racing trimaran. The first time i launched it I really felt the leech was really open. So I mounted a Barber Hauler on each sheet. Boy did I go downwind fast! Of course we never sailed a course more than 100d AW. I was much faster and deeper downwind. Relative to cruising that simple addition gave the sail a much larger range. Cheap and easy to do. A frictionless ring is all you need attached to a block.

[arsenelupiga]

Originally Posted by fxykty

Names are funny, but most come from racing.

Gennaker is generally useful for any cruising cat to fill the gap between genoa and spinnaker (hence the name!!) for close to beam reaching in lighter winds. It is basically equivalent to a racing (monohull) Code 0. As the code numbers increase the sail becomes fuller.

Screecher is a specialised cat sail for lighter wind upwind, generally used by cats with self tacking jibs to fill the hole upwind. It is basically equivalent to a racing (monohull) J0. It is a straight luffed upwind sail that is flown in front of the main structural forestay from a bow pole.

Both sails are flown with a bottom up furler with torsion rope to provide a tight luff. Membrane sails are now being developed that have their own structured luff and don’t need a separate torsion rope. This is lighter weight and requires less halyard tension - 2:1 halyard not needed.

Our cat came with a 120sqm gennaker that sets from our 1.4m bow pole and hoists to the 7/8 hounds just above the forestay. For comparison, our self tacking jib is 35sqm. The gennaker must be set outside the cap shrouds as the clew is within 1.5m of the stern quarter block when fully sheeted in and the leech is too full. It is triradial cut Dacron - bloody heavy and about 30cm in diameter in the centre of the furl. It is on a furler with a torsion rope luff rope. The halyard is 2:1 Dyneema cored and is tensioned to about 3 ton luff tension.

We can sail up to 40 AWA in anything from 3-10 knots TWS (our boat manual says maximum 15 knots AWS). Our boat speed is 100-120% of TWS in this wind speed range. But note that the 40 AWA works out to near 90 TWA. The gennaker is definitely not for upwind work. But it is a lovely, albeit heavy, sail to keep moving in lighter winds.

The gennaker works down to 90 AWA in lighter winds and down to 150 AWA in stronger winds. But generally above 12-15 knots AWS our jib is nearly as fast and with a lot less pressure on the rig and boat.

Our next sail will be a screecher. It will be cut with a hollow leech to fit inside the cap shrouds and sheeted from the aft end of the cabin top. It will be about 75sqm (sister ships that have genoas instead of self tacking jibs have 50sqm genoas). We will make it from Dyneema membrane for shape and weight. It will also be furled and with a structural luff we can use less halyard tension.

This sail will keep us to about 80% of TWS and provide a TWA of 50-55 degrees - a decent VMG of 50% TWS so we can sail faster upwind in light winds under 10 knots than with our jib.

wow, thanks for the clarification. will print it out and read every day.

How do you check that your luff tension is ~ 3 T . That sounds extremely tense.

According to your definition, i have laminated gennaker. Screecher seem so specialised sail that hard to find justification for $$$ and space and also for energy that one needs to swap sails as wind oscillates. I get tired of that pretty quick, not one of these racy types.

My plan is to attempt to use gennaker as screecher as well, because is laminated and can take loads. Not ideal shape but if can get couple extra 0.1 kn VMG out will be excellent. Such conditions, sea flat enough and wind <11 kn and steep upwind course are less than 1% so far in my experience.

[Happ]

Originally Posted by arsenelupiga

wow, thanks for the clarification. will print it out and read every day.

How do you check that your luff tension is ~ 3 T . That sounds extremely tense.

According to your definition, i have laminated gennaker. Screecher seem so specialised sail that hard to find justification for $$$ and space and also for energy that one needs to swap sails as wind oscillates. I get tired of that pretty quick, not one of these racy types.

My plan is to attempt to use gennaker as screecher as well, because is laminated and can take loads. Not ideal shape but if can get couple extra 0.1 kn VMG out will be excellent. Such conditions, sea flat enough and wind <11 kn and steep upwind course are less than 1% so far in my experience.

They are put on a Roller Furler and have a very wide range of use in angle as well as wind speed. That’s why so many multis’ have the. Simply roll it up when you don’t want it. As to Luff tension that’s simply set by how far you want the draft forward. It’s not nearly as critical on a cruising boat. Worrying about halyard tension is more for those who that like that kind of stuff. Just hoist it when you think you are going to be sailing in 10-15 knt and you are sailing over 45d off the wind. Simple. Don’t over think this.