What makes a sailboat go fast?

andrew
I like the idea of a retratcing center board. but i can see the advantage of retracting it going up wind. the only advantage i can see is downwind. but that being said. nobody here is putting down you idea. the reason i started this thread was to some how prove me wrong with my own ideas. i have alot of respect for dick and will and lester, yes even greg. these guys can look at what i am saying and say " hey this guy is just plain dumb, or hey he might be on to something. and we can improve the desin. i wanted to know if a wide beam hull . like a ts2 is the fastest we can get. are we at the limit? or is bantock ikon the wave of the future. ? your idea of a retracting centerboard has merit build it? grab an old IOM hull and redo it. get some proof that your idea is sound.
does anybody have any ideas where the rockerpanel should be the deepest? i start my boat at the bow =0 and the stern being 10. by last 4 IOM had a 60 mm rocker at station 5. i am thinking of moving it forward? maybe st 4
cougar
long live the cup and cris dickson

Ahh, This is getting more like it…
Why do you need to pull up the daggerboard? most really fast ‘dinghys’ ie skiffs like 18 footers, int 14s, 49ers dont pull up the dagger downwind anyway, you need the lateral risistance to sail angles with an assymetric kite (if you want to go really fast downwind you dont want to be barn dooring dead downwind as I’m sure you know; you need to be sailing faster than the wind). Theres only two real ways of doing what you want to do, the first one is add floats and call it a tri, the second is moveable ballast of some form, ie a canting keel. Basically you got to face it, those are the only ways of getting any large jump in performance unless somone really comes up with somthing totally new. Messing around with a little bit of rocker here or more bouyancy there will not make any big jumps in performance.

Luff 'em & leave 'em.

My thought is that if you’ve got a boat that uses a movable ballast (aka crew) then that “crew” would be sailing the boat by the seat of their pants. Since it is difficult to control a R/C sailboat by the seat of my pants, my first inclination is to try installing a rate/HH gyro (R/C helicopter gyro) and hook that up to the servo controlling the movable ballast. Then if you set it up right, you’ll be able to have precise instantaneous weight transfer control over your sailboat.

I also think that the same thiing will work on canting keel sailboats as well. In fact, I can see the keel responding to every puff of wind.

Rcher- What you do with a ck boat most of the time (in powered up conditions) is put the keel at max cant and sail it like any other r/c boat, downwind it gets tricky to keep it all level if its gusty, but not imposibe, it just takes some getting used to…

Luff 'em & leave 'em.

lol
i guess the rockerpannel meens nothing. hell the hull shape meens nothing. lets just put a canting keel on it and it will be fast
i give
you win
cougar
long live the cup and cris dickson

No, not saying that at all. Okay here goes again; If you build a boat weighing 1kg, with 1sqm of sail that can hold that sail area in the same amout of wind that a 4kg boat with the same sail area does it will be faster no? Given that both have reasonable/suitable hull shapes etc.
You can not mention fast boats and IOM’s in the same sentance! If you want close, large fleet raceing with a overly expensive boat, go IOM. But do not think they are fast, there is nothing you can do within the rules to make a truly fast boat!

Luff 'em & leave 'em.

Ah, but you CAN make a fast IOM. If you want fast go fast electric,why limit yourself to something a archaic as wind.

Thanks
Don
Vancouver Island

[:-banghead][:-banghead][:-banghead][:-banghead]

Luff 'em & leave 'em.

Cougar,

The question you asked was so general that folks are going to provide answers that are all over the map. If you wanted to know about what hull shapes would make your IOM go faster, then you should have asked that. Don’t get mad as us because you asked the wrong question…

Matthew,

I agree with you about the CK boat. I would say that most of the time on a moving “crew” ballast boat you would have a similar situation. You will generally move the crew weight only to respond to large changes in wind strength. You will respond to smaller changes by simply allowing the boat to heel a little bit or perhaps sailing a little higher. Once you get above some critical windspeed, the crew would be at “full hike” all the time and then you would need to respond with feathering. Anyone who has raced full size dinghies knows how to do that.

  • Will

Will Gorgen

<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by wgorgen

Matthew,

I agree with you about the CK boat. I would say that most of the time on a moving “crew” ballast boat you would have a similar situation. You will generally move the crew weight only to respond to large changes in wind strength. You will respond to smaller changes by simply allowing the boat to heel a little bit or perhaps sailing a little higher. Once you get above some critical windspeed, the crew would be at “full hike” all the time and then you would need to respond with feathering. Anyone who has raced full size dinghies knows how to do that.

  • Will

Will Gorgen
<hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>

Will, being the incredibly well designed human beings that we are, you know that we are a crucial part of sailing dingies. And as such, we sail our dingies by the seat of our pants and by the feel of the sheet lines. And you’ll notice, that as we are sailing, we are moving with the sailboat responding to <font color=“red”>minute </font id=“red”>changes in helm. Some of us are not a lump of lead sitting at full cant. [:I][:)]

In any case I still think that that incorporating some sort of sensor or gyro on our R/C boats to replicate the “seat of pants” response can help make sailing smoother. And we know generally the smoothest sailor is the fastest sailor.

I actually do have a GY401 Futaba gyro that I think I’m going to try on my Marblehead. And what I will do is hook it up to the sail winch. My hypothesis is that once I set a heel angle then the gyro will do it’s best to maintain the heel angle regardless of how much the wind huffs and puffs. The nice thing about the GY401 is that from the transmitter, I can switch it off or use two different gain settings. However the one flaw that I see in my idea is that the sail winch will not be responsive enough to the gyro.
But it won’t hurt to try it. [:)]

Rcher,

There are a lot of things that we do on full size boats that we simply don’t do on model boats. For example could you imagine sailing a full size boat that had only one string to pull? event the simplest boats have adjustable vangs. Most higher tech boats have far more strings to pull that you could ever control with a radio.

I like your idea of the Gyro. Hal robinson on his canting mast US1M used a pendulum system to control the mast cant. He found that he had to add a lot of damping to keep the thing from going into uncommanded oscilations. If that gyro has damping, i would play with that to make up for the slowness of the servo…

  • Will

Will Gorgen

The GY401 gyro is a heading hold gyro and has adjustment for delay and gain. You can also get the GY240 Gyro which is the same as the GY401 but without the transmitter switch hookup. If I have time, I’ll try it this weekend. [:)]

Canting keels seem like they might be the way to go for absolute speed, but seeing as I don’t really have a winch capable of canting a keel right now (I’m a bit in the technological dark ages) I’m trying on-deck ballast. I’m currently building a 24" boat with an 18" rack on the deck that will hopefully allow the boat to carry a large bit of sail pretty flat. Seeing as I’m a bit on the slow side in terms of reactions (one reason I like monoslugs over multis) I’m going to put hollow sealed caps on the ends of my rack (basically training wheels or little floaties:-). Hopefully, if I capsize, the weight in the keel and the bouyant force will be enough to right the boat. And just in case, when I get this boat up and running, it’ll just run close to shore for a good while;-).

Graham

Graham -

Continue with your ideas, just make those ballast ended capped thingies a bit longer, and you will be playing with a multihull !

Just stretch the main hull out to 1 Meter, and grab the rig off any other 1 Meter for this project. You’ll be sailing a MultiONE or darn close to it !

Will be interested in seeing how it works out. Pluse, with the extra hulls it will keep the end tips of ballast rack out of the water!

iwas just thinking
what if you put a 2 pound wieght on a threaded rod. then put the rod along the beam at the mid piont. then all you would need it to reverse the motor and you would move the wieght to either side of the hull. but just inside the hull. and you would not have to worry about water getting in?
but i dont know if that would work
cougar long live the cup and cris dickson

OK Cougar - you’re gonna laugh at this.

When I was about 12 years old (many many years ago), I built a model land yacht which I mounted on a platform with wheels off a skateboard. It had no form of RC control - totally free sailing. You set the sheeting, the direction of steering, and let go.

This thing was ballasted by a hunk of lead suspended on a two foot pole out to windward - just as you are considering.

It needed a good breeze - but boy, did it fly! The only way to catch up with it was when it wiped out.

Just the thing to keep a 12 year old boy happy for hours. [:P]

Muzza

not laughing
the 2 foot pole would be a tough sell on a boat hull. my idea was to put it in a 9 inch beam hull
nothing i have seen so far is nuts
cougar
long live the cup and cris dickson

Cougar and Graham, Try it!! If nothing else, you may have a seed of a good idea and it just needs to germinate and grow! For example, just find a broken computer printer and I’ll bet you can find the components (threaded rods,pulleys, etc), you need to use for moving your weight back and forth.

Hey Guys -

we are recycling printers all the time. Not sure how you can get 110 volts out to the middle of the pond …safely, but if you really want to try fooling with the printer idea and the cartridge carrier, let me know. For the price of UPS, I’ll be happy to ship you one (or several).

ummmm - Cougar, not sure if I can send to Canada. Had one heck of a time getting schooner drawings up to “Alberta Clipper” and those were only paper. Between anti-terrorism, tarrifs, import restrictions and just pain-in-the-butt freight/import issues, you might just ask a local PC company - or school, or government facility for a free broken one.

If you are here in the States, and don’t mind waiting until a retired one is available - email me and I’ll keep a lookout for one.

Cougar,

I like your idea of shifting ballast below deck. It would be, of course, illegal in most classes, but this thread has never been about making a boat go fast LEGALLY…

I think you might find easier ways to move the ballast than threaded rods, though. Heck, use one of your spare winches and rig up a pulley system with a sliding rack and “hoist” the ballast to windward. That should be pretty easy and a lot quicker than a threaded rod.

Of course as long as the ballast is below deck, you are only going to get a small lever arm out of it for righting moment. The bigger the lever arm you can use, the less weight you ewill need to generate your righting moment. thus, you can end up with a lighter boat (which we know is faster). That is why above deck racks like this one are preferred: http://www.microsail.com/pbs.html

  • Will

Will Gorgen