What is best Sail design for a Catamaran?

[JPA Cate]

Weavis,

I know you're clewed up, and all, but have you looked at the rigs on John Hitch cats? Now there's a new world, for us monohullers. ;-)

[weavis]

Originally Posted by Ann T. Cate

Weavis,

I know you're clewed up, and all, but have you looked at the rigs on John Hitch cats? Now there's a new world, for us monohullers. ;-)

Double headsail!
I loved this comment..

"There are some design flaws (that curvaceous deck which sheds the waves so well also sheds things our guests inadvertently leave there!"

Am reading the sail design comments....... thanks Miss Ann.

[44'cruisingcat]

Pretty hard to beat a headsail only rig for ease of use. But perhaps not so hard to beat them sailing to windward...

Or, how about a triple headsail rig? I sailed once on Zenataos, (formerly Wired) which has three headsails. The two "standard" John Hitch sails tacked off the bows, and a blade jib off a pole and bridle arrangement in the centre.

Oh yeah, a mainsail too...

ZENATAOS....... Zen And The Art Of Cruising

[davecalvert]

There are good reasons that most catamarans are designed with large full batten mains and furling genoas.
The most efficient mains have multiple full battens and wide square tops. Although, a wide square top main is not the most practical for cruising. The long diagonal head batten is not easy to deal with. Best to go with a rounded head with a few battens spaced closer together but, all parallel to the boom for easy stacking.
Properly designed and built genoas can be large but still reefed down with a good shape.
Bow sprits with code 0 sails round out a good three sail inventory giving the best all around performance.

[tomfl]

Originally Posted by davecalvert

There are good reasons that most catamarans are designed with large full batten mains and furling genoas.
The most efficient mains have multiple full battens and wide square tops. Although, a wide square top main is not the most practical for cruising. The long diagonal head batten is not easy to deal with. Best to go with a rounded head with a few battens spaced closer together but, all parallel to the boom for easy stacking.
Properly designed and built genoas can be large but still reefed down with a good shape.
Bow sprits with code 0 sails round out a good three sail inventory giving the best all around performance.

I am of two minds about big square tops. The PO of my boat was six four and the first thing I had to do before I could sail my boat was put two steps on the mast so I could get up high enough to attach the halyard to the sail. On the other hand once the sail is up I love the speed. I would also point out a square top is sometimes said to be the first reef. When a gust hits the top of the main will twist and spill the wind. I am very willing to deal with the downsides of a square top for the additional better sailing qualities when it is up.

I also think it is a good idea to have two head sails. I fly a working jib and a screecher on a bow spirit. Having two slots (which have to be adjusted correctly) is a real performance boost.

There are certainly easier to handle rigs. I saw a guy who cut down his mast five feet, added a couple of feet to the boom and put in a system to roll the main around the boom. He was also flying a club footed jib. A dream to deal with, but I have to wonder about the performance.

[weavis]

Originally Posted by tomfl

On the other hand once the sail is up I love the speed. I would also point out a square top is sometimes said to be the first reef. When a gust hits the top of the main will twist and spill the wind. I am very willing to deal with the downsides of a square top for the additional better sailing qualities when it is up.

Tom... in a 15 knot breeze with down wind sailing....... what would you say your average speed is. And in asking this question, what is your hull speed rated at?

Seawind 1000.

[tomfl]

Originally Posted by weavis

Tom... in a 15 knot breeze with down wind sailing....... what would you say your average speed is. And in asking this question, what is your hull speed rated at?

Seawind 1000.

Steve Marsh (the Seawind dealer in Stuart, FL) told me Seawinds should sail at 2/3 more or less of the wind speed. I commonly sail at 10 knots in what I will call a 15 knot breeze in 3-5 foot seas downwind in normal conditions. I have seen the GPS register 12 knots and have taken pix of the GPS at 11 knots. This is with the screecher and working jib and an unreefed main. The GPS has recorded a top speed of 13.9 knots but I suspect I was too busy with other things to notice it.

A Seawind 1000 like mine with three foot stern extensions is somewhat under 36 feet which would mean hull speed by conventional measures would be around eight knots. My understanding is that a catamarans speed is to some extent determined by the ration of the hull length to the beam. Another consideration is how much weight the boat is carrying.

I have comfortably sailed at nine knots in the bands of Andrea last year in probably 8-12 foot seas and I would guess twenty knots plus with two reefs in the main and a working jib.

I am not a young man and tend to sail single handed a lot, not to mention lots of folks are better technical sailors than I am. I have no doubt others could sail the boat faster, especially with a crew.

[weavis]

Originally Posted by tomfl

Steve Marsh (the Seawind dealer in Stuart, FL) told me Seawinds should sail at 2/3 more or less of the wind speed. I commonly sail at 10 knots in what I will call a 15 knot breeze in 3-5 foot seas downwind in normal conditions. I have seen the GPS register 12 knots and have taken pix of the GPS at 11 knots. This is with the screecher and working jib and an unreefed main. The GPS has recorded a top speed of 13.9 knots but I suspect I was too busy with other things to notice it.

A Seawind 1000 like mine with three foot stern extensions is somewhat under 36 feet which would mean hull speed by conventional measures would be around eight knots. My understanding is that a catamarans speed is to some extent determined by the ration of the hull length to the beam. Another consideration is how much weight the boat is carrying.

I have comfortably sailed at nine knots in the bands of Andrea last year in probably 8-12 foot seas and I would guess twenty knots plus with two reefs in the main and a working jib.

I am not a young man and tend to sail single handed a lot, not to mention lots of folks are better technical sailors than I am. I have no doubt others could sail the boat faster, especially with a crew.

Thanks for that. I was aware that you sail single handed, but was not aware that you had the extensions. It is not really a sluggard of a boat! I had the pleasure this afternoon of going for a 2 hour trip on a Catalac 8 and we were doing about 6.5knots with a good breeze.

I kinda have got used to the lesser speeds, (6 knots in my Seawych and Taurus and Eventide) on smaller boats so for you to have these good averages, its encouraging.

As for hull to beam ratio, Although it has effect on hull speed, I understand that the design itself with lesser chines and sharper edges improves the speed through water.

Your boat is a very impressvie design overall.

[tomfl]

Originally Posted by weavis

Thanks for that. I was aware that you sail single handed, but was not aware that you had the extensions.

SNIP

In flat water with both of the 9.9 Yamaha outboards wide open I go around 6.9 knots, maybe seven downhill. A friend of mind had a Seawind with four foot stern extensions and was hitting 7.1-7.2 knots with the same outboards but a little order.

[smj]

Originally Posted by tomfl

In flat water with both of the 9.9 Yamaha outboards wide open I go around 6.9 knots, maybe seven downhill. A friend of mind had a Seawind with four foot stern extensions and was hitting 7.1-7.2 knots with the same outboards but a little order.

On your boat with a clean bottom we could usually get low 7's at full throttle. On our old Seawind with the 4' stern extensions upper 7's. And yes, 15 kts of wind would usually give pretty consistent double digit speeds on a good point of sail.

[tomfl]

Originally Posted by smj

On your boat with a clean bottom we could usually get low 7's at full throttle. On our old Seawind with the 4' stern extensions upper 7's. And yes, 15 kts of wind would usually give pretty consistent double digit speeds on a good point of sail.

AJ when I went out with Josh on his boat he hit 7.1 in Sisters Creek (current unknown) in the big flat area around Whiskey Creek. When he went out with me we hit 6.9 in the same place. He commented his boat was faster than mine due to the extra foot in his sugar scoops. Josh did have some problem with a prop on one of his engines and that might explain some of the speed drop.

When I was heading East from Big Pine to the harbor I was not able to even go five knots but the tide was rushing out of the Gulf under the Seven Mile Bridge and there was the normal ten knot East wind. Not saying a clean bottom is not important but current and wind seem to be more important for a top speed.

[smj]

Originally Posted by tomfl

AJ when I went out with Josh on his boat he hit 7.1 in Sisters Creek (current unknown) in the big flat area around Whiskey Creek. When he went out with me we hit 6.9 in the same place. He commented his boat was faster than mine due to the extra foot in his sugar scoops. Josh did have some problem with a prop on one of his engines and that might explain some of the speed drop.

When I was heading East from Big Pine to the harbor I was not able to even go five knots but the tide was rushing out of the Gulf under the Seven Mile Bridge and there was the normal ten knot East wind. Not saying a clean bottom is not important but current and wind seem to be more important for a top speed.

Hey Tom, I think the difference was Josh's boat had the older 9.9's which were much larger engines, probably not much speed difference because of the added 1' of stern. I'll admit the figures I gave were both taken after we hauled and had a new bottom job. I must admit though that your boat definetly seemed faster under sail and lighter on the helm for some reason. Never been able to figure that one out.

[tomfl]

Originally Posted by smj

Hey Tom, I think the difference was Josh's boat had the older 9.9's which were much larger engines, probably not much speed difference because of the added 1' of stern. I'll admit the figures I gave were both taken after we hauled and had a new bottom job. I must admit though that your boat definetly seemed faster under sail and lighter on the helm for some reason. Never been able to figure that one out.

I was only on Josh's boat a couple of times so can't really say a lot about it. I do think my helm is very light but I spend time trimming the sails so the boat is so well balanced I can go below and get a drink and the boat is still on course when I get back in the cockpit.

As soon as the dentist says my root canal infection is cleared up I will do some more sailing tests.
https://www.facebook.com/photo.php?f...type=1&theater

[weavis]

Originally Posted by tomfl

I was only on Josh's boat a couple of times so can't really say a lot about it. I do think my helm is very light but I spend time trimming the sails so the boat is so well balanced I can go below and get a drink and the boat is still on course when I get back in the cockpit.

As soon as the dentist says my root canal infection is cleared up I will do some more sailing tests.
https://www.facebook.com/photo.php?f...type=1&theater

Would be interesting to see if the factory made changes to the rudder or shape if the year manufacture is different, or if the extensions themselves account for the difference.....

[smj]

Originally Posted by weavis

Would be interesting to see if the factory made changes to the rudder or shape if the year manufacture is different, or if the extensions themselves account for the difference.....

Same rudders, one is a 1996, the other a 1995. The one we put the 4' stern extensions on had a heavier helm before the extensions were added. We adjusted the cable which helped quite a bit. I didn't realize the difference until we sailed both on the same day.