Purpose of a centerboard/daggerboard on a small sailboat?

Just a little trailer sailor. About 4 meters in length, totally open - no cabin or deck. It's a pretty simple boat, so I'm thinking he should be able to put it together without too much going wrong.

 

as long as you have some proper plans for him, and he follows them exactly, you should be fine. Just do not let him deviate from the plans on things that are not easy to fix later.

There are in fact many sailboat owners that do not have a clue about how the sails work but still manage to sail around. I have a hard time keeping my mouth shut when I hear an affluent yacht owner say really stupid and out dated ideas such as "you need camber in the sail so it will catch more wind", or "you need to get the jib set so you increase the slot effect on the mainsail".

 

That's pretty much been my M.O. already. Whenever he tells me anything that I'm not sure about I consult my resources, although I've already been studying sailing long enough on my own to understand most of what he says. I was just a bit shocked to hear him so adamantly defend his ignorant position about something so fundamental and, to my mind, common-sense obvious.

I have been keeping a close eye on things, and he's well aware of the fact that My Money = My Boat, so I have final say on any design elements.

 

Well, I showed my friend all of the answers posted here and he still maintained that he was right and that all of you are wrong. Of course, that brought us back to the original conversation and, in the course of that, some new and interesting information did come to light which I think bears mentioning.

Apparently, the impetus for my friend's erroneous assertion that a centerboard's only purpose is to keep a boat upright was an experience he had long ago in which he pulled his daggerboard (which was weighted with 20 lbs. of steel plate at the tip) up while sailing on a beam reach, after which his boat promptly rolled over.

"Okay," I said. "It was the fact that you moved the center-of-gravity up by however many feet that caused your boat to tip. The weight of the steel at the end of your daggerboard is what was keeping your boat upright. It has nothing to do with water pressure."

"No," he responded. "The only reason that steel is there is to pull the daggerboard down when I put it in the slot."

So, in other words, he's confused, but about something slightly different than what it appeared at first.

I didn't bother arguing with him about his new error in thinking, and I didn't volunteer to ask any experts about it either, because he didn't respect the opinion of all of you experts the first time.

Anyway, thank you for the help, even though I still wouldn't have gotten a beer out of it because he apparently knows more than all of you guys.

Thanks!

 

On occasions like this, the best thing you can do is simply admit your failure and misunderstanding in the situation and offer him the first beer out of the cooler, the next time you're out on the wet stuff. Mt point being, there's no sense in ruining the prospect of enjoying a beer, while out for a sail, regardless of who had to eat what, just before the phffffistttt and first swig. Personally I have little time for those that can't accept physics and/or the other dynamics involved and usually just avoid these types of conversations, if only to get more free beer when they loosen up after the first few.

 

there is a term for people like that: invincible ignorance. they do not want to be confused by facts because their mind is already made up. When I was younger and less sensitive to such ignorance I used to try and convince people of the actual facts, which leads to a lot of anger and frustration. So PAR's advice I had to learn the hard way, do not bother with them. You will be much happier.

One engineer that used to work for me used to give me this advice: do not attempt to teach a pig to sing, you will only frustrate yourself and annoy the pig.

 

Reminds me of the sign my dad had on his desk

"Don't confuse me with the facts. My mind's made up"

 

Well, I don't like beer, so none was ever actually at stake here, but I've realized that there's no way I'll ever be able to correct the flaws in his reasoning. I figure, as long as he knows that it helps to have a heavily weighted board sticking down in the water, it's okay if he doesn't know exactly why.

And it isn't like he's totally ignorant. He really has great taste and instincts otherwise. For example, he loves PAR's Rocky design, although he would combine the two designs pictured and build it as a gaff-rigged ketch. I like the gaff sloop, just as it appears on the site, but he and I think alike on almost everything.

 

Have him drop me an email and I'll send him a drawing of a proposed hermaphrodite gaff ketch, I did a while ago. I don't include it in the plan set, simply because it's not a popular option. A fully gaff ketch would be difficult on Rocky, placing the "sticks" in less than desirable locations. The hermaphrodite has a gaff main, but a sprit boomed Bermudan mizzen, which I think is the best way to handle this sail on a small ketch.