I've read catamarans don't point as close to the wind as mono hulls but don't have any experience on one. Can someone explain why?
Catamaran pointing
- Thread starter Marc Bergmueller
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Ok, here is a try..typically, a well sailed and trimmed cat can generate a lot more hull speed in a given wind . That hull speed causes the apparent wind direction (wind direction over the deck) to shift forward.. The faster ya go, the more forward the apparent wind.. Ya have to fall of a little to keep the sails from stalling.. That is the lower pointing angle, the amount ya fall off (even with close hauled sails) as speed increases.
Some of the hull forms of catamarans are not going to allow them to point as high. Many cruising catamarans do not have daggerboards or centerboards and only have relatively shallow stub keels. This can prevent them from pointing as well as their daggerboard/centerboard equipped brethren.
Two problems with a cat to go upwind: first, they're way wider so it's hard to get the jib in tight around the shrouds. Second, as the cat "heels", the leeward hull digs in and provides more drag, which pulls the boat off the wind.
And, of course, there's the apparent wind thing, but that's true with fast monohulls as well.
druid - anyway, it's more FUN to go off the wind!
And, of course, there's the apparent wind thing, but that's true with fast monohulls as well.
druid - anyway, it's more FUN to go off the wind!
Marc... read this:
http://www.thebeachcats.com/index.php?name=News&file=article&sid=59&theme=Printer
BTW, Druid.... both your points are incorrect. Headsails are normally sheeted inside he shrouds and catamarans don't heel, that's why people like them for cruising. Please, read the link.
If you're really interested in knowing the difference between catamarans and monohulls.. read this:
http://www.thebeachcats.com/index.php?name=News&file=article&sid=59&theme=Printer
BTW, Druid.... both your points are incorrect. Headsails are normally sheeted inside he shrouds and catamarans don't heel, that's why people like them for cruising. Please, read the link.
OK, I read the link. I've also read "Catamarans Offshore!" many times, sailed a few cats, and built one when I was 16. My comments stand: If you're flying a bigger genoa if the sheets are inside the shrouds it makes it hard to set it off the wind. So some cats route the sheets outside. And although they don't "heel" (unless you fly a hull), the leeward hull is pushed deeper in the water, which creates more drag. On a beach cat like a Tornado, the "perfect" set is to have the windward hull just kissing the water: in this case the leeward hull has virtually ALL the drag. On a cruising cat you don't usually go that extreme, but the difference is still evident.
druid
Nope, still missing on point 2.
All things being equal - they never are - cats point about the same . However, most cruising cats carry a lot of accommodation space and treasure shallow draft, and those factors would hurt any design. There are mono-pigs out there too. As for performance cats, they can point high with boards, but even then they generally go faster a bit further off the wind, because they are not up against hull speed limits.
With either the Hobie 16 or Prindle 16/18 the hulls are asymmetrical and will only point well with a hull deeply immersed.
All things being equal - they never are - cats point about the same . However, most cruising cats carry a lot of accommodation space and treasure shallow draft, and those factors would hurt any design. There are mono-pigs out there too. As for performance cats, they can point high with boards, but even then they generally go faster a bit further off the wind, because they are not up against hull speed limits.
I'd point out that comparing beach cats and cruising catamarans are really a bad idea...as they're very different beasts. Also, while cats don't heel that much, they do apply pressure to the leeward hull.
I'd point out that the article you're linking to is primarily discussing BEACH CATS and SAILING DINGHIES, and has little relevance to larger cruising monohulls and catamarans.
I'd point out that the article you're linking to is primarily discussing BEACH CATS and SAILING DINGHIES, and has little relevance to larger cruising monohulls and catamarans.
The reason I ask is I chartered Sunsail 384 (leapord 38) in BVI in June and have no Cat experience. The biggest boat I have sailed is a Catalina 36. Just wondering what to expect.
Yes...but, the original question asked about catamarans in general, it did not specify type. Most of the answers did not differentiate between the two. Thank you for pointing out the obvious.
Perhaps someone could explain how pressure on the leeward hull affects pointing.
A flat ride, for one thing, and lots of interior space. Sailing wise... tacking the boat requires you to backwind the jib, and sheet the main in to help turn the boat through the tack, especially in choppy water. On a heavy monohull, momentum carries you through the tack most times.
On a monohull, the vessel's heeling will tell you when she's overpowered. On a small cat the hull will fly, but on a cruising cat you'll have to look for other indicators. This is where you ask the charter staff to show you what to look for when you get checked out on the boat.
Have a blast.....
SD is right - too many differences. But...
Hobie-type boats - the hulls are asymmetrical and the depressed hull works as a keel. Hobies don't point for spit unless one hull is lifting, and crews will move to leeward in light winds to make them point... but this has nothing to do with cruising.
Cruising cats or cats with symmetrical hulls and boards - very little difference in pointing with heel; however, they do go faster on any course when one hull leaves the water and reduces wetted surface and wave impact resistance. Since a cruising cat should never approach lifting a hull, this is academic.
In general, non-performance cruising cats will not point as well as a common cruising monohull for many reasons, but they will be faster off the wind. They are generally as fast as a monohull 4-6 feet longer, over an average cruise. Not theory, but general observation. Bring a Gunboat or an Open-60 and everything is different!
Note: Don't back wind the jib but do drop the traveler as you come through the tack. Backwinding the jib will pop you right into irons on some cats, as you will lose all speed and thus all control. When you release the jib, by the time you get it sheeted back in, you will be stuck. Of course, boats vary, but the back winding thing for cats is more myth than fact. It works on some beach cats with big rudders, but not on cruisers with small rudders.
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