Centerboard vs Daggerboard

What's really the difference? I'm not looking at performance differences, more of the language. What makes a daggerboard a daggerboard, what makes a centerboard a centerboard?

A daggerboard is a foil that is pulled straight up and down in a slot, like the Laser or like most high performance catamarans these days.

A centerboard is a foil that rotates up and down in a much longer slot, like the Tornado and the Hobie 17, for instance.

from "the street" a catamaran centerboard is commonly referred to a board that rotates up into the hull as on the Tornado, Hobie 17, or the new Nacra 5.8. A daggerboard is one that fits into to a slot in the hull and raised up through the hull.

A centerboard can have the capability of swinging back if hitting something underwater. A daggerboard does not.

A daggerboard is usually much longer and narrower than a centerboard and is a little more efficient at generating lift in the water.

So you can lift out a daggerboard, but you can't lift out a centerboard?

Well, you CAN lift a centerboard out on shore if you need to for maintenance or something. But otherwise, when you are sailing, when it swivels up, it is hidden inside the hull. As Jake said, if you hit something, it is able to "kick up" into its slot, whereas if you hit something with a daggerboard, it's, "Uh-oh."

In other words, you never really see the centerboard and it is not in your way above deck. But there is a roller (or something) that goes along the slot on the deck, and that rolls forward or aft, depending on whether you are raising or lowering the centerboard.

Got it now.
While we're at it, not to hijack the thread, as it's in the same line of questioning. What is a gybing daggerboard?

http://www.philsfoils.com/designTips.html#gybinghead

the head of the board is shaped as a trapezoid to allow the board to pivot a small amount and provide more lift. Same idea can be accomplished with a properly shaped head slot and rectangular head.

Mary:

Don't ALWAYS count on that. <img src="http://www.catsailor.com/forums/images/graemlins/frown.gif" alt="" /> When I first got my Hobie 17 and was new to them, the first time I took it out at Deep South I forgot to pull it up. When I hit the shore it snaped the pivot point off like snapping a twig!!!!! <img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" /> <img src="http://www.catsailor.com/forums/images/graemlins/mad.gif" alt="" /> <img src="http://www.catsailor.com/forums/images/graemlins/ooo.gif" alt="" />

Doug

But it didn't open up the hull, which might have happened, if it was a daggerboard <img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" />

True. But centerboards aren't cheap either. About $250 a piece, Just remember to ALWAYS pull then up BEFORE you get close to the shore!! Hard lesson learned. Can't wait to experience daggerboards when I get the Blade. <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" /> <img src="http://www.catsailor.com/forums/images/graemlins/tongue.gif" alt="" />

Doug

Doug

I broke so many more H17 centerboards than N20 daggers.

It happened so often, I made a "half a mold" of the Centerboard pivot so I could rebuild it after I broke another one.

And it may not be "Uh-oh" but damn if my boat didn't leak like hell from those centerboard slots. Come to think of it, so does my current boat though :P

Thanks a million to all.
Pardon my continuous questioning, but I've been out of cat sailing for quite a few years, and much has changed. In any case even though I did own two previous cats, I never got into the whys and hows of sailing or racing; both of which I'd like to understand better now.

We've got some friends on island. They decided to take a late afternoon whale watching cruise off the beach on a 50 foot cat equipped with daggerboards. As they were heading out the captain announced this was the first time in a month he'd been on the water so they were going to use the sails instead of motoring.

He headed out into the channel and beyond the wind line at a pretty good clip ignoring the fact that it was pretty rough and a number of the paying customers were getting a second taste of their early dinners. This was caused by him hitting on a babe back by the helm.

After finally realizing the passengers were losing weight fast, he tacked around and headed back to the beach while still chating up the babe.

The big head had had all its blood diverted to the little head which meant our lusty skipper had completely forgotten the boards were down until the boat came to an abrupt stop short of the beach. No one was hurt but one board was jammed into place.

The captain, who's blood has flooded back to the big head, and crew attempted to free it with block and tackle but it wasn't to be. The boat was finally taken to the Lahaina harbor where the somewhat lighter passengers were limoed back to their original departure point.

I'll hazard a guess that it'll be more than a month before our lightheaded skipper returns to the water.

Hey, you've left out an important detail:

Did he score?

Inquiring minds needto know!
<img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" />

Doh! I forgot to ask and my friends left yesterday.

If he did, then the rest is incidental really, ain't it?
<img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" />

I thought that a centerboard has to be in the center of the boat/vessel.

Now the daggerboards in my P-19 are not located in the center of the boat .... as niether are the boards in my H-18, so I call them daggerboards. Can you imagine the confusion when you tell a first time sailer to "pick-up the centerboard" and point to the edge of the boat ....

So MY definition is centerboards are located in/on the centerline of the vessel, daggerboards can be/are located else where on the boat then on the centerline of the vessel.

"It's in the words": comedian-Galligher

Of course this is my personal opiniun.

HarryMurphey
H18mag/#9458, Fleet54/Div11
P19mx w/spin /#86, CRAC

As stated above, centerboards are internally stored (in the hull) and usually "kick up" (slide back into the hull) when they hit an obstical.

Daggerboards can be removed from the boat and stored seperately. Daggerboards do not kick up of they hit something... they either stop the boat abruptly or rip through the hull and slowly stop the boat as it sinks.

The word dagger would suggest a stabbing motion such as the direct push needed to thrust the blade style down through the hull. It is implausible to think to describe a swinging board as such.

A centerboard is in the center of a hull; not the center of the vessel.

I agree with the dagger comes straight out from the top, center board swivels down from with in. The theory that a centerboard is one that is in the center of the hull does not seperate itself from a daggerboard, which is in the center on the I20, my 18SX, my Laser, and my old sunfish.

Why is it called a "centerboard" if it can be located any where on the vessel. I'll agree that a centerboard pivots, but if it can be located anywhere on the vessel why isn't it called a "swing board" or "pivot board"???

Ex: the mast on a catamaran is located where??? On the centerline of the vessel. The boards on an I20 maybe on the cenerline of the hulls but that is different then the "centerline" of the vessel. My P19 has pivoting/swinging boards but they are not on the center-line of the "vessel". I remember a definition from "Power Squadron" classes that a centerboard trunk was located on the "keel-line" of the traditional monohull sailboat.

Maybe the issue is that when "centerboard" was origonally defined nobody thought of a Catamaran.

HarryMurphey
H18mag/#9458, Fleet54/Div11
P19mx w/spin /#86, CRAC

I would be inclined to think centerline of hull(s) not vessel.

I agree that daggerboards go in a slot and centerboards pivot, but there are always exceptions and inconsistencies. Many scow classes have bilge boards. Since the boats are designed to be sailed heeled they put a board on each side of the boat that will be the lowest point when heeled at the optimum angle and the board is vertical in the water at that heel angle. In addition the board has toe in to reduce leeway. All the classes I'm familiar with use pivoting boards.

http://144.92.9.188/hoofers/sailing//Manuals/The%20Scow%20Manual.htm

There are also leeboards. Most of the examples of these that I've seen or read about are pivoting. I believe that I've seen lee daggerboards on smaller boats where you would just have one blade that you move from one side of the boat to the other.

http://en.wikipedia.org/wiki/Leeboard

John

Thanks John,

Maybe I should call the "boards" on my P19 Bilge boards as that seems to be the closest definition that fits as Wikipedia defines a ceterboard as being on the boat's/vessel's symetric axis. which sounds like somewhere in the middle of the tramp to me.

HarryMurphey
H18mag/#9458, Fleet54/Div11
P19mx w/spin /#86, CRAC

The wikipedia definitions for both centerboard and daggerboard were obviously written by a monohull person. <img src="http://www.catsailor.com/forums/images/graemlins/smirk.gif" alt="" />