A model 49er?

Been sketching out my next boat… but don’t want to reinvent the wheel if I can help it.

I’ve got in mind a planing monohull similar or based on the 49er, with only enough keel weight to make it stand up in the water, but with sliding ballast.

I’m thinking it should be about 4’ long, maybe a little more (I’ll have to measure my car…)

The idea I have for the movable ballast is that it’ll be able to be moved fore and aft behind the mast as well as from side to side… I think I’ve just about got the mechanics of it sorted in my head. It strikes me that in order to balance the boat on all points of sailing, the weight ought to be able to move in in 2 dimensions.

I’m well accustomed to the idea of moving 2 transmitter sticks in both axis at the same time, so am looking forward the the challenge of sailing such a boat…

I’ve learned that model sailing boats can be made to plane… I’m hoping this one will be born to it!

Has anyone tried anything similar? Has anyone by any chance got any lines for the 49er or the equivalent? Failing that, I think I know where I can get access to a full sized one… any tips on measuring it to make a scale copy?

Cheers,

Philip Rawson

www.flymodels.co.uk

Phillip -

you can look back at some of the old Doug Lord and Will Gorgen posts (some are in the multihull section) Doug used to point to a Melges boat that was photographed, but every time I pressed him to bring it out, there were excuses and I can’t say I ever heard of anyone seeing it in operation.

JayDee and I worked out a mechanical system for a multihull (cat) but the biggest problem is being able to anticipate the action of the boat. Not to throw water on your ideas, but when you are on board, you can feel things that are happening to the boat. When you are on shore (and often at great distances) you can only react AFTER the boat has done something (capsize ?) and often by then it is too late! On my big cat I can feel the windward hull getting lighter and I can feel the slight weather helm as the boat starts to lighten up before raising the hull. Along with the “feel” I can hear the sounds of the boards and rudders as they move through the water at a faster speed; I can hear when the hull just breaks loose from the surface; and the sound of the diamonds and shrouds when the cat is “loaded up” are other things not able to be detected from a transmitter while standing on shore.

Of course, there is always a gyro use, but somehow I have trouble using something like that as part of sailing. Might just as well program a PC and have it run an autopilot and forget sailing and just sit back and watch it sail itself. I’ll probably get flames from the helo-guys, but when we start inserting electronic aids to do “our” work as skipper or crew, somehow it has lost it’s appeal to me.

If getting the lines off a 49er is a bit too tricky, you might like to try this link.

http://www.sailingsource.com/cherub/desp90.htm

The line drawings of a number of Cherubs, from the 1950s right up to the late 1990s are there. These, together with a study of the photos at www.49er.org (49ers upside down, inside out, pitchpoling etc) will give you some really good ideas for a skiff design. You could come up with something that looked very much like a 49er, even if it wasn’t lines-perfect.

Sounds like a fun project.

Muzza

Philip

Sounds like a great project.

With the canting keek I would say that it would need to be very quick in its movement. My Canting keel on my F100 moves from hard over to hard over in about 4 seconds but if I used a faster winch you could get it down to 1-2 seconds easy which i would say you will need I would seriously look at the gyatt winch for this I am using a hitec 725bb and it is fine at the moment but would like to try a gyatt soon.

Any way good luck any more questions let us know.

Cheers Blair

gappy.

He wants to use a deck system not a canting keel.

Philip

if yo can’t find and good hull lines, drop me a note, i might be able to come up with something qwick for you.

Moderator
-Dan

Philip,

You may also want to check out this site: http://www.aquataurmodels.com/ I think they are in your neck of the woods. In any case, there are some interesting ideas in there on how to use movable ballast to right a capsized boat.

I have been working on a study to mount a similar system onto an RC Laser that would significantly reduce the sailing weight and wetted surface area of the appendages while maintaining or even increasing the righting moment of the boat.

My design (on paper at the moment) includes a “skipper” that moves from side to side much like the aquatuar system. I have added a second degree of freedom to the skipper by being able to move his “feet” for and aft. since his body is attached to therack system at the “waist” and the ballast is in the “head”, this will allow for significant fore/aft movement of the ballast at all the hiking positions. I have done some ballast motion studies out of Lego blocks and have refined my geometry to allow the side to side motion to be accomplished by an arm while the fore aft motion is accomplished by a line attached to his feet and fed to a winch.

By the way, as long as you can design the system to right the boat, then allowing the boat to capsize becomes part of the game. The skill required to keep the boat from tipping adds to the skill and challenge of the sailing experience. Anyone who has sailed a Laser, 49er or other skiff knows that you can (and do) capsize.

  • Will

Will Gorgen

That was always PopUp Mfg’s claim to fame with their big cat…

There is nothing - absolutely nothing - half so much worth doing as simply messing about in boats. Kenneth Graeme, Wind in the Willows.

Thanks for the replies chaps,

I’ll reply to Dick first… Have you ever seen an RC plane prop-hanging? It’s the equivalent to balancing a broom on your hand by radio control… two sticks on the tranny, two axis each… all moving all the time, just to keep the plane in a completely unnatural and unbelievably unstable attitude. I’ve never done anything more difficult, but can do it… I’m hoping the 49er will be very slightly easier to control.

I don’t believe gyros (or mixing come to think of it) does anyone any favours when it comes to personal satisfaction, I certainly won’t be using one…

Gappy… I’m looking at using a quite high power winch system for the side to side ballast control… If the servo is part of the ballast, then it’s not wasted weight. I’m looking at the use of the motor and gearbox from a cordless drill… much faster than a normal servo. There’s a lot I haven’t worked out on this bit yet…

Muzza, Dansherman and Wgorgen… thanks for the links and support. I’ve got an aeroplane to finish so I won’t be starting the project 'till after Christmas. If you come up with any more ideas and links, It’d be much appreciated.

Cheers,

Philip Rawson

www.flymodels.co.uk

<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by philiprawson.rcsailing@nt

Thanks for the replies chaps,

I’ll reply to Dick first… Have you ever seen an RC plane prop-hanging? It’s the equivalent to balancing a broom on your hand by radio control… two sticks on the tranny, two axis each… all moving all the time, just to keep the plane in a completely unnatural and unbelievably unstable attitude. I’ve never done anything more difficult, but can do it… I’m hoping the 49er will be very slightly easier to control.

I don’t believe gyros (or mixing come to think of it) does anyone any favours when it comes to personal satisfaction, I certainly won’t be using one…
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Hi Phillip - point I was trying to make, is that moving a couple pounds of lead and or sheeting a mainsail takes more effort and time than trimming fast acting servos to “prop-hang”.

I believe - strictly my opinion which no one has been able to prove differently by sailing one yet - is that by the time you realize you need to shift weight, it may be too late or the winches too slow.

Not saying it can’t be done; not saying it won’t work; not saying a capsize that is self-recovering isn’t a practical solution … I am simply asking … if you aren’t on board, and if you can’t feel the boat starting to quickly heel, how do you determine “when” to move the weight and “where” do you move it… out to the windward side, out to the side and also to the rear, or simply to the rear?

In your airplane example, it seems you “knew” you were putting the plane in that position first and had only to balance to keep it there. Same on the boat - if you heel a catamaran on purpose onto one hull it is much easier to keep it balanced there - than to be caught off guard and keep from dumping from a heavy wind gust that couldn’t be seen.

Regardless - it will be interesting to see what you come up with, and how well it sails…and recovers.

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

Hi Phillip - point I was trying to make, is that moving a couple pounds of lead and or sheeting a mainsail takes more effort and time than trimming fast acting servos to “prop-hang”.
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True… but I’m planning for that. I won’t be using a standard winch servo for the side to side weight shift. I’m looking at using a much bigger motor and higher speed system. As for the sail winch, I’ve learned from my Tornado that the movement needed to dump air from the sails is smaller than I first thought. I’m now setting the sail with the stick and controlling the heal of the boat with the trim…

<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>
I believe - strictly my opinion which no one has been able to prove differently by sailing one yet - is that by the time you realize you need to shift weight, it may be too late or the winches too slow.

Not saying it can’t be done; not saying it won’t work; not saying a capsize that is self-recovering isn’t a practical solution … I am simply asking … if you aren’t on board, and if you can’t feel the boat starting to quickly heel, how do you determine “when” to move the weight and “where” do you move it… out to the windward side, out to the side and also to the rear, or simply to the rear?
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The fore and aft weight shift should be a bit less critical then the side to side… I imagine that the fore and aft will be used to trim the sit of the boat rather than keep the thing upright.

<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>
In your airplane example, it seems you “knew” you were putting the plane in that position first and had only to balance to keep it there. Same on the boat - if you heel a catamaran on purpose onto one hull it is much easier to keep it balanced there - than to be caught off guard and keep from dumping from a heavy wind gust that couldn’t be seen.
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Putting the plane in the prop-hanging position is the easy bit… A plane will naturally want to fall over, but can fall in any direction… and does. To recover from the plane falling over it’s usually neccesary to use throttle, rudder, aileron and elevator control, all at once, at the right time, by the right amounts… The plane is never completely stable and is wanting to fall over all the time… And then there’s the effect of the wind…

Controlling just the sheet and ballast on a boat strikes me as being potentially easier…

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Regardless - it will be interesting to see what you come up with, and how well it sails…and recovers.
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Thanks. The more I read up on weight shift boats, the more tricks I’ve found to cheat a little… A small amount of ballast on the keel is one… making the wings boyant is another… every little helps.

cheers,

Philip Rawson

www.flymodels.co.uk

“The fore and aft weight shift should be a bit less critical then the side to side… I imagine that the fore and aft will be used to trim the sit of the boat rather than keep the thing upright.”
Eeek! Have you ever sailed a 49er or anything similar? Without a kite I would think offwind fore and aft movement will be the most important, nothing will be keeping the bow up! Very it will be tricky in waves and gusts to say the least…

Luff 'em & leave 'em.

Ok you want a planing monohull, but I just want to ask what for? If you want to be the fastest around the buyoys, a monohull is not the answer. Real 49er will loose to real Tornado on any Upwind-downwind track. Sure, 49er is equal speed or faster in certain conditions downwind, but it is crappy upwind compared to Tornado. Having sailed both of them I also can say that if you dont know what you are doing, you cannot even launch 49er from the dock. With tornado you can get off even if you have very limited experience from sailing. What i mean is that your experience from your tornado might not be the right source for information when you are trying to predict the behavior and based on the prediction design the moveable ballast system of your 49er.

I am not trying to sand your slick, RC is the right scale to try out things and people trying out new stuff are Most welcome. If you just want to try out some extremities of what you can actually control via rc, then a planing monohull with moveable ballast without any keel weight will be your thing to do. Also we RC-sailor must remember that most of us are very rookie RC-pilots. Controlling the boat via rc doesnt put the controlling system even near the system limits. Helicopters and fast stunt airplanes are much harder to control, even high speed rc-cars are harder to drive.

However, RC-sailing has so many other aspects than just controlling the boat.

  • HJ

“Expertice is gained trough mistakes. However repeating
same mistake is not learning but stupidity.”

Matt is spot on about the fore & aft trim, if the 49er didn’t have a kite, it would be pretty hard to sail downwind without moving fore & aft, any high performance dinghy needs both fore & aft & side trim to be sailed properly, the higher the performance, the more fore & aft trim helps, just look at any of the proper skiffs (12, 14 used to be, 16 & 18’ers), they all need fore & aft trim to sail properly…

I see said the blind man to the crippled nudist who put his hands in his pockets & promptly walked away.

maybe you could make a scaled down international skiff moth, now that would be cool, would probably be harder to sail as well…

I see said the blind man to the crippled nudist who put his hands in his pockets & promptly walked away.

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

Ok you want a planing monohull, but I just want to ask what for?
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What for… now there’s a tricky one… 'cos I’ve got an image in my (naive) mind of a boat skimming across the lake at great speed. The 49er has, simply captured my imagination… and that’s a great motivation to build one.

I don’t race… indeed I know only two other people who own boats… I sail when the conditions aren’t right for flying model planes.

<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>
What i mean is that your experience from your tornado might not be the right source for information when you are trying to predict the behavior and based on the prediction design the moveable ballast system of your 49er.
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Point taken…

<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>
I am not trying to sand your slick, RC is the right scale to try out things and people trying out new stuff are Most welcome. If you just want to try out some extremities of what you can actually control via rc, then a planing monohull with moveable ballast without any keel weight will be your thing to do. Also we RC-sailor must remember that most of us are very rookie RC-pilots. Controlling the boat via rc doesnt put the controlling system even near the system limits. Helicopters and fast stunt airplanes are much harder to control, even high speed rc-cars are harder to drive.
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I’m motivated in my model plane flying by the desire to learn a new aerobatic maneouvres. I’ve got many years of plane flying under my belt. If I can make one clean reach across the lake using weight shift at it’s limit, I’ll be a very happy man and will know it can be done. BTW, learning a new trick with a plane can take many hours of practice.

Philip Rawson

www.flymodels.co.uk

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

Eeek! Have you ever sailed a 49er or anything similar? Without a kite I would think offwind fore and aft movement will be the most important, nothing will be keeping the bow up! Very it will be tricky in waves and gusts to say the least…
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I’m listening… This sort of advice is what I need to make the project a success…

Philip Rawson

www.flymodels.co.uk

<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>
What for… now there’s a tricky one… 'cos I’ve got an image in my (naive) mind of a boat skimming across the lake at great speed. The 49er has, simply captured my imagination… and that’s a great motivation to build one.
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Thats a perfectly good reason to build one :slight_smile: The comments are coming mainly because people do not want you to be disappointed, and from people (like me) who see the building as the evil necessity, rather than fun experiment :slight_smile:

Those guys saying that 49er wont survive or even plane properly downwind without genaker are perfectly right. Genakers force vector is at least 30 degrees upwards and without the lift coming from the G the boat will nosedive. Last summer I missed a genaker hoist on a buyoy in 15 knots of wind, we accelerated without the genaker giving the lift and nosedived & flipped the boat in 3 seconds, both of us hanging as far out in the rear as we could. What I am saying here is that a 49er planing downwind requires other elements too than just moveable ballast to stay upright.

The outcome is this: 49er might not be the easiest platform to acheive your dream nad there might be some more suitable boats to scale. However scaled down 49er has its coolness factor and somehow i feel you donw want to cross the lowest fence :slight_smile:

<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>
I’m motivated in my model plane flying by the desire to learn a new aerobatic maneouvres. I’ve got many years of plane flying under my belt. If I can make one clean reach across the lake using weight shift at it’s limit, I’ll be a very happy man and will know it can be done. BTW, learning a new trick with a plane can take many hours of practice.
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I have been Pit-crewing and been the flagman for my friends who fly electric Pylon ( triangle race ) and Combat stunts. My comment was pointed to us “Only sailing-nonpilots” who dont have the stick-experience you have.

  • HJ

“Expertice is gained trough mistakes. However repeating
same mistake is not learning but stupidity.”

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

Those guys saying that 49er wont survive or even plane properly downwind without genaker are perfectly right. Genakers force vector is at least 30 degrees upwards and without the lift coming from the G the boat will nosedive. Last summer I missed a genaker hoist on a buyoy in 15 knots of wind, we accelerated without the genaker giving the lift and nosedived & flipped the boat in 3 seconds, both of us hanging as far out in the rear as we could. What I am saying here is that a 49er planing downwind requires other elements too than just moveable ballast to stay upright.
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I hear what you say… Could there be conditions, ie, wind strength where the boat could still plane downwind without the genaker, balanced by the crew? I’m thinking that on a model, the sail area will need to be matched to the wind strength and the ballast used.

I’ve got a lot to learn (part of the challenge). At the moment I’m in the process of putting weight shift on my Tornado… it’ll be interesting to see what I can do to about it’s tendency to bury it’s nose in high winds and whether it’s possible to counteract with weight alone.

<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>
The outcome is this: 49er might not be the easiest platform to acheive your dream nad there might be some more suitable boats to scale. However scaled down 49er has its coolness factor and somehow i feel you donw want to cross the lowest fence :slight_smile:

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I’d be interested to follow up on any suggestions for a boat to model mine on…

Philip Rawson

www.flymodels.co.uk

Phillip -

just an observation - depending on circumstances, adding weight to your Tornado may increase chances of capsize, as you have just added to displacement, and if hulls aren’t buoyant enough to handle the extra weight, (and able to accelerate in the gusts) you may find the added weight more of a problem than a solution. All would depend on the starting design displacement of the boat, and how far off the designed waterlines the boat is floating. As you may be aware, some are concerned in the monohull MISTRAL to be concerned about reducing the cross section templates to take into consideration the thickness of the planking and glass.

I am not directing the following at you - only making it as a general statement - “in making changes to a model, of a percent of weight, change of buoyancy location, increase/decrease of waterline or beam, and finding a negative reaction, it seems too easy to blame the boat - and not the modified design parameters.” I am sure you wouldn’t expect a plane to fly (or stunt) if you added more weight, so I would caution others to keep the “design specifications” in mind when someone modifies a design and the results aren’t as positive as expected.

We seem ( in the multihull area, especially ) to quickly blame the design for capsize - and seldom take into account the experience of the skipper, the speed or strength of the winch/servo, the size of the sail area or the height of the rig… all we see is another multihull that capsized. If it happens to a 49er (or other modified set of hull lines) the same kind of reputation may follow. I am not saying you (personally) would be critical, but someone will read any less than positive results as a negative view of the boat, the process and what was being attempted. As noted before - good luck with the idea -as some of us in the multihull community will be watching to see how it works and if it makes sense to add the added weight to our current lightweight boats.

Philip,
Your comment about movable balast needing to move in 2 dimensions resounded with a concept I thought up some time ago, when a former member of this forum brought up the topic. Instead of trying to slide the ballast laterally on a track, why not have it be mounted on a swinging arm that would rotate across the transom as it went from beam to beam(or behind, if the rig had no backstay). This would have the added advantage of being able to have weight far enough aft to better resist pitching moment in a run. Maybe you wouldn’t need a kite after all [:D].

Then to take it to the next level, devise a electro-mechanical device that would automatically perform this function. Some sort of pendulum sensing heeling angle could send an appropriate signal to a dedicated (and very fast) servo. I’d have to talk to one of my engineer friends to get a clue as to how this could be made to work, but I’m sure it’s possible. I realize that an automatic device such as this is pretty much a sacrilege in model boating circles, but it may be necessary to reduce complexity for the skipper & provide the quick response to keep these thing upright.It also addresses the concern raised by Dick & others about the difficulty sensing subtle dynamics when not on board the boat.
Bill
ps wasn’t the old freesailing Braile steering gear an “automatic” device?