Hi BB, The pipe needed needs to be round as this has better torsion capabilities than square.
As mentioned most variations have been tried and what failed then discarded.
The Lefroy Mini is a colmination of 30yrs of trial and error.
Part of the design is for the main spine to flex a little, this in tern takes some pressure off the mast and rig.
My advice spend the $30 - 50 on the right tube and build the yacht only once.

My suggestion to ANYONE wanting to build a yacht ... build a Lefroy Mini ....follow the plans, don't change much and you will get a yacht that just goes.... just ask Cisco!!
If you want to radically change things you are 30 years behind !!!

Now , now kidswhen I tried the 60mm round it was a risk , as it might not have worked, but it did.
Soooooooo, I would be grateful to you if you tried out the 50mm x2mm square.
It may not work , but then again,I would be really happy if it did. some of the builders have got away with really thin trampoline tube, and wouldnt have put my money on that working.
try using the 50mm , but dont add any high bracing,(A frame) ie still build a tortional frame.. However I would also recommend that you stick to the wheelbase dimensions of the mini. Larger yachts have been built with 50x2 and they do bend .
If it works we have then moved the MINI design to a lighter and simpler place. I have a big stack of the stuff, so I will be eagerly awaiting the results.
you will still need some 60mm round for your mast base, to fit the mast into it.
all the windsurfer mast weve converted for landyachts have had about 600mm of tube placed up inside. it ususally has to something around 44mmOD to fit.
those masts with no reinforcing have all split.
OOOROO from the GURU

beachball57 said...

what happened to the spirit of experimentation

My thoughts were coming from past experience, I have over the years seen 2 yachts constructed sort of like a class 5 but never got there.
The yachts performed poorly, the owners became disallusioned with the sport and left disappointed.
I applaude experimentation.... but if by chance the yacht didn't perform to expectations would you think it is you or the yacht?
And alternately if the yacht flew is it you or the yacht?
If you made the yacht to the plans and you were a little slower or faster then the variable is you !! and you will have piece of mind of how you compare with other sailors.
If your slower then with practice you will improve and if your faster .... others will be experimenting to catch you !!!

what you say is true, and there's no doubting that, however as i have said in many past posts i am not here to race against anyone, if i wanted to do that i would have stayed in drag racing or something, where life begins at 300k's an hour, to me it is the fun aspect that i seek, and if for some reason something that i built didn't work or "perform" then what's wrong with going back to the drawing board and changing something here or there, isn't that how we learn,,, yeh sure it is good to take something that is tried and true and get out there and start sailing, but i ask you this, where did you guys learn what worked and what didn't ?? was there already aworking plan that you could draw from, or was it trial and error, eg experimenting, isn;t that half the fun anyway, seeing what works and what doesn't for oneself,, look i thank all for the helpin answering my many questions , some of which i thought might be a little stupid, but then i remembered that there is no such thing as a stupid question,,,,,,,,so thanks guys for all the answers so far and for the answers to come, i have all the steel to build a mini according to the plans but i'm going to "experiment" a little with another one that i'm building along side the mini just to see what it does
cheers
[}:)]
bb

HI BB
Found this pic of an aluminium frame landyacht that was made in NZ some time ago
called a Windthrill Looks like from the sail number it might have been the second one made

That rowlock set up would be a worry. thats how we used to snap rowlocks back in the early 80's.I much prefer the BLOKART setup as most beginners and some more experiened sailors tend to let the sail out at the wrong time.
so is this the chicken or the egg?

These units look very much like they would qualify as prototypes for the blokart.

I tried the web site but it seems to be defunct. Maybe you could ask Paul Becket about them next time you see him Hiko.

They appear to have all the elements of a very good mini yacht. It would be great to find out more about them spec and performance wise to have more to add to the knowlege pool.

And the IMac Duo. The example on the trailer is here in Bundaberg. Very heavily built. Both the owner and I agree it could be built a lot lighter. He told me that when he set it up and got in it just took off and I think he said he crashed into the fence.

He has taken a mould off the seat and made a couple. I think he has made them a little on the heavy side too.








I think she likes it. Maybe hers is a quiet kind of humour.

Always abit of worry when you put all the effort into a good comfy fibreglass mold and somebody whips out a mold for themselves.
Those breezers have been around for some time. they were quite clever in that you bought them as a smaller yacht ( around the AUST cl 6 spec ) then you could extend the chassis to make them into a class 5.
That steering pedal adjustment is pure Seagull , very nice to have on a yacht.
Does IMAC still have the NZ rights to Seagull yachts?
Saled one on Lake Lefroy , doing an advert for a japanese lemonade commercial.
Ian brought 4? all the way from NZ for the shoot

cisco said...


So, how good is an IMAC Breezer?

Who knows?
Be nice to ask somebody who has one

Yeah, a solid rod would have to be better than that set up and easier to do too. I have seen an adjustable tent pole used as a steering rod. Cheap, effective and very adjustable.

Krikey that looks uncomfortable!I dont think Ciscos knees would be too happy like that for long

The foot pedals are adjustable for length and the handle at the end is for push starting Thanks cisco

Quite often with product development its the "Right one at the right time" which gets off the ground.

Another case was the beta v VHS home VCR war, beta had better technical specs but VHS won because the inventers gave the design at minimal cost to anyone that wanted to build them, the beta system was licensed to sony and sanyo only
And more recently the war between HD DVD and BlueRay video playback systems.

If the blokart and Windthrill came out at similar times then the blokart fitted the public needs at the time.
I think some of the blokarts winning ideas are the portability, and one design, and the sales pitch from blokart itself....They seem to sell a "Lifestyle" rather than just a yacht.
And just maybe the Windthrill was just a new style of yacht, but without the salesmanship.