I am hunting out parts to build my own Lake Lefroy Mini and have a chance at this.

"Stiff windsurfer mast, length 4.45 m. Killwell, black lightweight Carbonfibre, good quality and good nic for age. Classic minimal taper very suitable for flat cut race sails. One piece. Other dimensions , Base external diameter 50mm, internal diameter 46mm, tapers to top outer diameter of 40mm. Missing top plastic bung though that is easily replaced."

If its suitable what size sail should I look for to go with it?

The LLFM will be a joint project with some boys from the local school. I have never tried a land yacht and in fact have never seen one "in the flesh" yet.

I'd search on here but I need to know fairly quickly and I am not sure that a search will give me the time to assimilate the info so I thought why not ask the "experts"

With the few LLM's I have put together it has never really mattered what mast we ended up using initially, as long as a sail would fit on it the landyacht would work to some extent. Our fussy criteria was that a mast was cheap and would fit into the mast base and not be too thick up top to slide into a sail pocket. What really mattered later was matching a sail to it, then things improved dramatically. Masts are a lot less common than sails here so I grab any that come my way at the right price. Spare masts are handy, You will have to reinforce the base of your one by the sounds of it with the 2mm wall thickness. This is where having a couple of expendable masts comes in handy, a thinner section shoved up inside the base for a metre strengthens it. Other wise fibreglassing the outside is needed which takes a lot more effort. The boom is easily made from cut length of mast as well. The LLM plans show this well but you may need to make the boom longer than plan depending on what sail you end up with.
The sail size to use is mostly determined by whether the mast can fit the sail pocket and have about 450mm sticking out at the bottom. To complicate things further the cut of the sails pocket may only fit onto slender tip masts and the mast will need to flex enough when hauled down to match the shape of the sail. There is no yes or no answer to what size sail in area square metres will fit, I have a tall narrow 4 sqm sail that needs a long mast and an old broad 6 sqm sail that fits on a mast 500mm shorter. With some dedicated sewing you can modify some sails to fit masts quite well, sometimes by just raising the haul down lower eyelet (Tack).

If you are going to the effort of building one land yacht, consider building a second frame at the same time. Cost wise it is very little extra, one more stop sign post and some short lengths of RHS, setting up to weld is a lot easier with the second one, you learn from your mistakes.
Once you get one going the boys will want another one to race against.
Searching on here will uncover many pearls of wisdom and save you / reinforce your trial and error results.
Good luck
Colin

Thanks for that Colin. I'll try to grab this mast then. As you say they don't come up cheaply very often. Come to think of it cheap sails don't come up often either. I have tried to find some local windsurfer clubs to see if any of their guys have one that they would sell (or donate). I found a couple online. One was in Christchurch in the South Island for $50 but they wanted $200 to freight it! There are a three at $200 each (2 x 5.5m and one 6.5m) that I might consider having a try for.

I like the idea of trying for 2 at the same time as I want one for myself and having 2 will give us the chance to have a wee competition to drum up interest and maybe make more as we have an ideal beach here in Whangamata (Google will help). Its not too far from Waihi and Tauranga where Hiko sails.

At the moment I am working my way through the plans to try and make them a bit easier for the boys to follow and so that we can make up a cut list for steel..probably going to use exhaust tubing as its cheap and easy to obtain and pilot weight is not an issue for me (80kg) or a bunch of preteen boys.

Having a good beach nearby means you have half the battle won already. The surface you run on influences how successful the initial runs will be. Our first run with the teenage Venturer scouts near Darwin was an afternoon on a beach with the strongest wind being when they arrived which got less and less over the next 2 hours. After an hour and a half only one yacht was left going piloted by a 12 year old younger brother and he was flying around and still getting a wheel in the air when all the others were sitting still. He did this with both of the LLMs we had there with entirely different sail combinations so it wasn't that one of the yachts was better than the other, just his light weight. Your boys will go well being light and will run rings around you in the lighter breezes.
Op shops, tip shops and word of mouth might be your best bet for getting sails though bargains do pop up on the internet selling sites as long as you can find a way to get them home. Living 900 km from the coast makes it hard to get windsurfer bits locally for us but I gather as much as I can when travelling away. All our masts are fibreglass one piece, no flash carbon ones here. Flexible masts will fit more sails than stiff ones but definitely need the base reinforced. Old 80s colourful dacron sails without any battens work, 90s flouro coloured dacron . mylar half battened sails work better and the 2000s clear full battened mylar sails work well but each one needs to be tweeked to suit a mast combination for best results. The fully battened sails that can hold their shape when just down haul is applied are the best all rounders. torn / tired dacron sails with the top third battened make really good storm sails with the bottom cut off and a bit of sewing, only short masts are needed too. People selling older sails as part of a shed clean out are really happy when they know the sails are going to be reused. Keep your eyes open for sheaves and pulley blocks at the same time these add up in cost very quickly if you need to buy new ones . A discarded catamaran / dinghy can give enough for a landyacht, 5 is the minimum to run the mainsheet happily with another couple to help with the sail downhaul.
Certainly build the first pair to the LLM plans though shifting the mast base forward 100mm will probably help with 6m plus sails. There are a couple of strengthening mods to the plans that should be done as well. The modular design of the LLM makes it really easy to play around with different axle / wheel combinations. The back end is very simple to cut, drill and weld so would give the boys an easy thing to start with. Hikos front mast base design is easy to build and makes the steering pedals easier to extend for shorter people but is a bit fussier with sail balance. Our original mast bases were too small for the ancient thick based windsurfer masts we started off with. A larger pipe was used on later chassis with 50mm PVC cut and slotted to fit around the base of any thin masts to take up the slack.
The fallshaw wheels are probably the easiest and best to use but I have never used them relying on a variety of tip sourced wheels instead. Certainly for competition the light weight of the fallshaws would give you an edge. Old steel 8" wheelbarrow wheels (with thick steel hub turned out to take 6205 bearings for a 25mm shaft) work well and can give the boys a chance to use a lathe needing about a 0.020" cut to fit the bearings. This can be done in a 9 inch Hercus if you have one at school. The original loose wheelbarrow bearings will work with light pilots but are high friction and will cut out quickly once the sand gets in. Golf buggy 8" wheels are wide and give good flotation on sand but will need a hub assembly bought / made up, the same applies to quad bike 8" wheels with smooth bald tyres. 8" alloy boat trailer wheels with either integral bearing hubs or a stud pattern work well and are strong but end up very heavy compared to a plastic hub, you will need stub axles to suit the bearings or hubs and stub to suit the pattern. Old trailer axles from the tip are cut up for this. For front wheels we have used 8" wheelbarrow, 8" boat trailer, 16" push bike and 20" BMX bike wheels, all have worked. Again the modular design of the LLM lets you undo a bolt and swap out a complete wheel assembly on the front or back to try out combinations.
Recently there has been a lot of posts on the LLM front end. This is well worth reading and clearly lays out what the plan drawings are trying to do. In a nut shell keep the steering shaft at about the same angle as shown (30 degrees ) and make sure the line of this shaft and where the front wheel contacts the ground vertically below the centre of the wheel intersect. I fit the rear axles and wheels to a frame, chock them and set the chassis height to level with a front support. A long straight rod is passed through the steering head and where it hits the ground is marked. The unwelded front end is then put in the steering head and clamped up when the wheel is at the right place, centred both vertically and horizontally. A couple of tack welds, another check then start welding for good. Once you work out the first front end, chassis number 2,3 and four go easily.
In my case the bodies have been easy, having access to fibreglass tubs( radomes ) from the fronts of old mobile phone antennas pulled off towers, while looking a bit rough these fit easily. If you know anyone in the communications game up there give them a try as what is pulled down is nearly always sent to scrap here in Australia. After about 2005 they changed the fiberglass material and it gets really shaggy when weathered for a decade on top of a tower. Initially hard to handle with glass fibres going everywhere a coat or two of acrylic paint sorts them out. The interior is clean and smooth having never seen the sun. The original NZ built Deltec phone whip antennas from the 1990's have made perfect booms being high grade epoxy fibreglass with thin walls and no shagginess at all. Later model panel antennas have gone to a cheaper all plastic casing.
We made up a bolt on tandem frame last year, the kids love it. The only change to an existing chassis is a front attachment point welded on, the rest plugs into the existing rear axle. There was a post on it last year.
If you get a chance to see Hiko's landyachts in action take it, you are lucky they are not that far away.
Have Fun
Colin

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When I was collecting sails and masts for Chook and Paul [aka "landyacht"], I used to keep a close eye on my local council's recycling depot, I would often score sails and masts for $10 each - if the sail was still fitted to the mast I got them @ $10 a set.

Even damaged masts and sails are worth grabbing - broken masts can be used for booms, or lengthening or reinforcing masts, while damaged sails can be recut - or used as donors to repair other sails.

When pickings were slim at the depot, I would put a notice on the Seabreeze windsurfing pages, asking for donations of old / obsolete / unwanted gear - and before long I would have more than enough for Chook and Paul.
The sound of 15 masts on the roof of the car, droning down the freeway is pretty much like being chased by demonic bagpipes

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GerryAttrick said..
ake up a cut list for steel..probably going to use exhaust tubing as its cheap and easy to obtain and pilot weight is not an issue for me (80kg) or a bunch of preteen boys.

nope .exhaust tubing isn't going to be any good. plus too tricky to weld .go looking for the galvanised 60mm OD for the spine. It will fit your masts and be strong enough