It solves the problem of the moment connection to the main beam without resort to exotic materials or construction techniques.

As for the rig, what I meant to say was that landsailors sail at very low angles due to their speed, for a watersailor you'll probably want a sail with much more shape.

Let me go done and measure the diameters of my class 5 landyachts.

But before you spend any money make sure you can get hold of the glue. If you can't then buying SS stuff will be useless.

Also we need to work out how to test this setup before we have anything build. See later in this post.

....

Okay may two landyachts have a "pod" of :

-1- 60 mm x 4 mm steel ; length 420 mm

-2- 62 mm x 3 mm steel (even appears to be 2.5 mm wall) ; length 240 mm

The second pod (-2-) is the newer landyacht and before this one the builder had build at least 3 others. He said to me that a few lessons learned went into my landyacht. I bought the yacht of yet another person so the builder wasn't bullshitting me.

The bottom section of two alu masts I have/measured are 48x4.5 mm and 50x8 mm, the first mast quoted is the youngest.

Most of these components were chosen on account of their availability. Both yachts and masts were homebuild. Some drivers like to have their pod diameter to be noticeably larger then the mast bottom diameter so that the mast can move upright when riding downwind after being raked far back during the upwind. This has to do with the position of the weight and wheels of the craft. These considerations shouldn't concern us. So I guess we'll be smart to start at :

pod : 55 mm x 3 mm steel length 300 mm

mast bottom 50 mm x 5 mm alu.

This should give a rather tight fit. And 2 inch alu tubing has a 50.4 mm outer diameter so that should be easy to find in the USA.

I'm looking to make the mast pod something like this :




Where the top pod (steel tube) is welded to the bend steel plate and which is then later glued to the top of the alu 80x2 mm mainbeam.

I would like to go close to 180 degrees bend on the steel plate as that really helps avoiding tensile stresses in the glue layer. There is no need to go for a full 180 degree. Something like 160 will be fine. Additionally having a large wrap around really increases the surface area, resulting in lower stresses in the glue layer overall. This makes the joint more acceptable of "bad" glueing.

I also give you the design of a class 5 mast, again note that several methods exist to build up such a mast. My youngest mast uses less components as the builder was able to find tubes will thicker walls then 2 mm.






I want to test this setup under some considerable bending loadings fore-aft and side-to-side and see if the glue holds.

This means we have to lock the ends of the 80x2 alu beam in some way. Does anybody have a good idea on how to do this in an inexpensive manner. Remember this 80x2 beam will be under alot of torsion loading. Simply jamming it in a vice will most definately not work.

We could glue the ends to a wide wooden beam, making sure that teh glue area is many times larger then of the mast pod. These beams can then be linked up by a crossbeam from which to mount the mainsheet system. We then only need to insert a tube acting as a mast with a boom supported by a high strength line and start pulling it apart.





If this fails after say 3 times the expect laods then we will cut the pod increasingly smaller till the vertical part of the pod bends or deforms then we know hoe tall the pod at least needs to be. On the "standard" landyacht this pod looks rather short indeed.

Would something like this work for you Flatlander ?

Wouter

I have used this glue (2015) many times with mixed success for bonding aluminium to aluminium. I have to admit I gave up on it in the end as I could not get consistent results. Some joints are still going strong after two years, some identical joints failed within days under light loads.

I believe the key phrase in the document you posted is "apply to a pre-treated and dry surface". What pre-treatment is necessary to get a high strength reliable joint? I thought that I was careful in my pre-treatment. I would anodise, lightly abrade then and then degrease with acetone.

The problem as I see it with these glues is consistency especially in the environments used by a home builder.

The following document lists the surface preparation and pre-treatment recommended by araldite.

http://www.huntsman.com/structural-adhesives/Media/surfacePretreatment_userGuide_Uk.pdf

I would be keen to hear from anyone who has successfully used this product and what pre-treatment they used.

Gareth
www.fourhulls.com

Let me get rolling on the metal fab and when complete we'll discuss the testing method further.

So that's in progress, what's next? <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Gareth,

I mostly used non-anodised aluminium in my glue jobs.

The alu-oxide surface layer does interfere badly in other situations like welding so maybe it does so too with respect to glueing.

Also preparation would probably scaring the glued area with small surface cuts. It needs to be as rough as possible. I think in the document they refer to sandblasting of the area that is to be glued. This does of course two things. It removes the alu-oxide surface layer and (can) make the area rought.

Also Gareth can you describe some of the joints where the glue failed. Can you have been suffering from peel-off failure ? Were you lift one tip of the jointed material breaking the bound and progress further each time breaking only a small portion of the bound instead of the whole bound in one go.

I have thought about this peel-off problem and I think that blind riveting the corners of the plate should take care of that to a large extend.

This is all very interesting and I would love to hear more about your experience.

With regard to anodising. I hardly have any anodized aluminium on my boat anymore. Only my mainbeam and mast are anodised. All the other stuff like rearbeam, boom, spi pole , mast rotation arm are non-anodised tubes. They hold up just fine. They turn a little dark overtime but that is it.

I won't try to hard to get the F12 components to be anodised. If I build one then I won't anodise the alu parts.

Wouter

I'll go after Dotan and see what their rudders costs. In short I'll work on the rudder setup.

The mast is pretty much finished as we just copy that of the landyachts. Ohhh, I will contact a friend with a "standard" landyacht and get his pod measurements and if possible his mast measurements.

The rearbeam design I will just take of my own F16 boat (3 years and still going strong), so that is finished as well.

I'll work out the traveller system and prep that to be test by someone as well. This testing will probably be done by myself as I have such a system on another landyacht (I need to clear out my shed !)

The only real thing we are left with are the hull really. Gareth, is that new material you are using for your hulls attractive for this F12 ? Any other suggestions in the way of material for the hulls. How much do you know about core matt hull production ?

hum, Like I said most testing needs to be done on the beam landing and pod, the rest has pretty much been developped to a good working design in both cats and landyachts already.


Wouter

Ohh flatlander,

We need to work out how big we are going to make the mast base plate.

Is it possible that you first get some info of the steel company and then get back with us. Then we can look over the design one more time and make sure we get everything right.

Currently I'm thinking a base plate of 160 degrees around a 80x2 tube with 100 mm length. That would be almost a 100x100 mm square. Thickness of the steel plate ? Well, find out till what thickness they can bend the plate around 80 mm tube.

That should be enough to use a safety factor of 3. In the final design I'd like more but I want the joint to break to give us at least some idea of where the limit it. If it holds up under everything then we still don't know much.

Wouter

I understand what you mean but I would first like to try to do without it. The simpler the better.





That is absolutely correct, however this only means that the F12 sails must be cut with alot more luff round. Actually the Moth sailboats use a sleeved mainsail very similar to the "Standard" landyachts. This gives me extra assurances that we can succesfully convert the class 5 landyacht rig to a sailboat. Will probably also need to widen the sleeve itself so there is enough room to have the straight mast slide through the curved sleeve.

Will do. This may entail a trip to a sheet metal shop as well as supplier so may not be tomorrow.

Flatlander,

I have time and I rather do this project at a calm pace then rush it.

The only reason I post alot of message right now is because I want to keep the momentum in the discussions going.

So take your time, lets try to plan well and spend as little money on development as possible

Wouter

Ok, If you must design a new boat.
Why would you start by developing a mast base that has poor repeatability in the home build arena. Glue seems like a bad idea.
If the boat remains a take apart as discussed then why not sleeve your pod(mast base). Slide on the front cross bar and then pin it.(does that make sense?) No bending required.
Just coping and a weld.
You could actually have mast rake adjustment if desired.
It could also be all aluminum if in a fresh water application.

I would think that Twintex would be ideal as it is both lightweight and very robust i.e. will take more abuse than anything else you could build with, but its not really suitable for homebuild.

I don't have any experience of core matt hull production.

Gareth
www.fourhulls.com

The problem Im having Mary is Im doing the pied piper at the club with one 420 and 14 kids doing circuits three in the boat in shallow on race day then I pack the 420 up and race. The kids that then go on their dads cat and have a blast think the 420 is boring and go of it for a month, meanwhile the women sit on the beach and watch. Now I have a couple of guys who would production line the homebuild with me and next summer we could have five or six cats in a class racing. We get a pile of kids out for sailing lessons for the next two weeks they come out religiously every year the kids love it and the parents love the child care. If the kids were excited they would nag the parents into submission on a yearly rental if I maintained them and organised storage and imagine the excitement when they go and compete at other clubs as a six or eight year old, of course the name has to be F10 or F12 I want them laying awake in bed dreaming of a blade at the moment theyre begging for a Moth. Imagine Phil and Wouter getting harassed by 10year olds for technical info and design improvements <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />. We may even end up getting some of the mums on the water. <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" />
yet another long ramble from me
regards

Situations and problems are different in different parts of the world and in different parts of the same country and even in different sailing clubs in the same region.

In your case if your club only has one 420 and all those kids, it sounds like a perfect situation for introducing a fleet of little cats. Hopefully, the "speed disease" would be contagious and spread like an epidemic throughout the other clubs in your area and then all of Australia -- and then to the rest of the world....well, at least in the PERFECT world, that is what would happen. <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

However, I have my doubts that U.S. sailors are going to want to build boats.

In your case, if you have a team willing to build some boats, I think it would be a great idea to REQUIRE the kids who are going to sail the boats to be involved in the building process, so they will appreciate the boats and take care of them and try to avoid running into each and other and damaging them.

This has been a very effective policy at Larry Hale's Scout Camp up in the Florida Panhandle. They get old Hobie 16's donated to them, and the kids, both boys and girls, have to do most of the grunt work to renovate them and also the regular maintenance work.

Maybe you should add a hose clamp on either side of the pod sleeve, going around the main beam. It should make a glue failure less catastrophic by keeping the mast captive if the pod rotates about the beam.

Just got back from Orange Bowl regatta, my kid's second year sailing there. He placed 30th out of 69 boats in the Opti Green Fleet. There were another 185 boats in the Opti Gold fleet. (the gold fleet was made up of 3 age divisions and had 4 sub-fleets rotating across 2 starts of approx 90 boats each.)

The Opti Green fleet there does a tremendous job of making the regatta fun for all beginning racers. It was something Joey very much wanted to do again after last year, even though he finished at the back of the pack last year.

http://www.coralreefyachtclub.org/index....p;edit_id=18535


I think this is a rather old picture from the Orange bowl venue.

Kids having FUN in Optimists?
According to the people on this forum that's impossible so it must be a lie.
How could kids have fun on such a low tech out dated boat?
The 250+ Opti kids in Miami last week had a terrible time. They just can't stop smiling for long enough to realize it.

[/quote]

Kids having FUN in Optimists?
According to the people on this forum that's impossible so it must be a lie.
How could kids have fun on such a low tech out dated boat?
The 250+ Opti kids in Miami last week had a terrible time. They just can't stop smiling for long enough to realize it. [/quote]

Yeah, but I'd guess that these kids have never been on a cat in their lives. Get them into something new that looks cool, is fast, and not too complicated and I guarentee they will be hooked. I started out on a Sunfish 3 years ago and thought it was the greatest boat ever. Then I discovered the catamaran......after that, there was no more Sunfish, and instead I bought myself an H16. What I'm saying is that if you give them the option of the F12 or the Opti, I guarentee they'd go for the cat. But personally, I don't think the purpose of this, "campaign" is to convert mono sailors to cat sailors. I think we should try to aim for the kids who have never sailed before, like kids who don't have parents who are active sailors, get these F12's running, then offer lessons or seminars to teach them. Parents who aren't active sailors don't want to lug a boat to the lake or wherever to watch their kid sail, they want to drop their kid off, know that they are supervised, and know that they will have a good time sailing (or racing) a bunch of club boats. I haven't had the time to read the whole post, but I think what Wouter is getting at with the low cost, low maintience boat is an excellent idea. I just dont think that we should be trying to convert mono sailors, if they want to switch because their friends are having way more fun on the cats then they are on the Opti's let them. But if they want to stay with the Optimist let them, but lets aim for the non-sailing chidren of non-sailing parents. That was me a few years ago, but I discovered sailing and eventually discovered the cat.......Also, I say stay away from the wave design and stick to a boat with atleast a single trap. It really doesnt add that much weight to put stays on a mast and I know that F12 sailors trapped out flying by Opti's and Lasers will certainly raise eyebrows in the mono fleets.

I don't recall anyone saying you can't have fun on a mono, but i might be wrong. I agree a new thread should be started 'F12 design and development'. Then we can avoid the arguement of monos v cats and juniors.

I've tried to keep my points as to the design, but failed miserably and started bringing the other aspects of which we shouldn't concerned about, e.g enticing the kids of monos to cats, instead of the real issue raised of getting kids to sail, for that I apologise.

Regards

I'm just guessing here, but I assume you are older than 8? <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Seriously though, I too started out 6 years ago (whooo...coming up on 7) and I can identify with the realization of what cat sailing offers. However, to an 8 year old kid, that's a lot of strings, a lot of power, and a lot of boat. More importantly, there are few kids that age sailing on these things and most 8 year olds (that I know anyway...admittedly not a whole lot of 'em) have a "pack" mentality and enjoy events where they are surrounded by a lot of other kids.