Alright guys, I have done plenty of reading up on your expert advice, and study of plans, drawings and pictures - but the time has come to start asking the stupid questions.
I am contemplating my first build and in the hope of keeping it cheap, I want to use materials at hand.
Let's start with the aluminium mast of a 16ft Windrush catamaran, complete with boom and sail.
Why am I not seeing any variation from the windsurfer mast you are all using?
Has anyone seen a stiff aluminium mast used successfully on a land yacht?
Any hints on how to stabilise it without the use of stays and standing rigging?
I am not too phased by building to within class specs and I will colour outside the lines where I see fit but I do want to build a yacht that works. There will be plenty more questions to come, look forward to advice from the most fundamental concepts right up to steering angles (all in time).
Reckon "lachlan3556" is the fella that will help you the most here.
www.seabreeze.com.au/Members/Profile/Details.aspx?member=lachlan3556
Really you have done a heap of reading and looking at designs on this forum and you ask a question like that?
Let me see what could possibly go wrong if I take a mast that is designed to be supported near the top with guy wires and insted take the wires off and stick the base in a foot long sleve? Do you realy think boat builders are so generous as to massivly over engineer their masts so that you can come along and use them in a way that was never intended.
If you have read these threads you should see that people have spent a truckload of time figuring out how to make yachts that work. Hell yes you can work outside class rules I do, but if you cant visualise the forces you are working with you might have chosen the wrong hobby.
Often lots of new people to the sport will spend considerable amounts of time, thought and often $$$$ in developing yachts. Remember it cost little or NO more to build a class spec using ideal materials than it does to build a yacht using existing re-cycle pieces.
In your case by using a WindRush cat mast / rig it will no longer suitable for your water yacht, so in other words you have wasted the entire boat / rig just to get a sail / mast. Where as a more suitable sail / mast can be picked up for just a few $$$ from the sailboard crowd.
Yep, it will work but you will need to adopt some design features that may make your craft more expensive and or more complex... So to begin with, you will need to use stay wires, and likely modify your mast length to make it landyacht appropriate. Not being a water sailor, I'm not sure of the mast specs for the Windrush Cat, but I would guess its too long for practicality (taking into account your 'simple' landyacht requirement).
Can you shorten your mast, or do you need it for your Windrush unharmed? 
Also, what have you got to transport your yacht and where do you have to sail???? 
Don't be disheartened, we can figure this out!!!
Thanks for your feedback guys. Gizmo, I am a sea sailor first and would not be considering wasting a working catamaran on a cut and shunt project. I have two spare masts, (both with booms) and the urge to put them to use is too great to resist.
Sylk, mine was a leading question, hoping to get a bite regarding the safety issue around wire stays and perhaps some feedback on whether a modified base on a truncated mast could work with only the front stay. Anyway the less I hear of your condescending uselessness from here on the better.
Lachlan, thank you mate for being forthcoming. I saw your vid of Kingston 2016 and have loads to ask. The first and simplest qestion is, if you had another aluminium mast, would you build with it again? I have a seven metre mast that I'm thinking about cutting back to 5.0 - 5.5. but if someone who has tried it tells me not to bother I will get back into the box.
hey Sav', where abouts are you??
If you are anywhere near me, you can borrow one of my lake Lefroy minis to mess about with and figure out what you want to do.
There are plenty of landsailers and iceboats that use stays (and stiff masts):
The biggest issue with re-using the cat sail is re-cutting it to be smaller and much flatter.
If you look at the sail on the yellow boat in the photo above you'll see just how flat the sail for a faster-than-the-wind boat has to be.
If you'll be sailing on softer or higher drag surfaces (ex. sand) you may need a bit more draft/power because you'll be sailing slower.
Land and ice sailing is all about apparent wind. On a good surface the apparent wind angle doesn't change much from about 10 degrees off the bow on any point of sail.
If you watch the windex in a video of a windward-leeward course you can see it doesn't change much upwind to downwind:
First welcome to the forum SeasickSav!
Having just recently gotten into land sailing myself maybe I can add some noobie insights. First figure out what type
of sailing/sailer you want. I believe the term used here is a "social sailer" (I call it a fun sailer), or one of the proven designs
that is more of the race/competition designs that abound here.
Both my sailers are of the fun type. The 2 seater uses different types of rig including both surf and sailboat rigs. while my
converted kite buggy is surf only. The smallest rig I have for the 2 seater is a 4.7 from a Laser boat up to a 6.1 lateen rig
from a Sunfish. This sailer needs a lot of low end grunt and the lateen rig provides this. Even if efficiency isnt top level the
yacht reaches respectable top speeds for the areas I sail on(mostly beaches). The lateen rig uses a very small mast built of EMT
and I use the carbon surf mast with the Laser sail set up with an EMT boom. All these masts are unstayed.
I just jumped in and built the first sailer with only overall dimensions in mind and it turned out well. From what I have seen
in a zillion vids almost anything that rolls will sail with enough sail area. Its just a matter of how well.
Dont be afraid to experiment, thats most of the fun!
Funny you should bring this topic up SeasickSav. I just got (practically) given three brand new (old stock) 8 meter sections of A class mast that were destined to be cut up and thrown in a skip. If I were to cut into them and start a new project/projects (can't though, will be hung, drawn and quartered prior to burned and staked on an ant hill) I have imagined a class 5 sized vessel (2m wide, 2.5m long) using a 4m wing mast (sitting on fuselage so you can use almost all the 4m length) and about 4m of sail area. I would support the mast with 3 stays, and use a tassie oak (25x190mm) rear axle for flex (concept stolen from Landyacht I believe ). 3 Fallshaw barrow wheels with good axles. I would imagine they could be nice little yachts. Plan for the future is to build 6 identical landyachts...
I know it would be better to build to class spec, however class spec masts are a real issue here in Aus. If anyone can point me to a source of round telescoping alloy for class 5 masts that won't set me back thousands, I'm all ears!!! If we could access masts, then I'd be all for class 5 spec yachts. Miniyachts are great fun, but I realise they aren't everyone's cup of tea (though you should really try one if you can!).
BTW where are you located?
Check out some of the yachts in the below vid, they were very good 'social sailors' 
Ex-yacht gear can definitely work.
One thing I can say is don't fit your sail to a mast using cable ties....
Design should also be built to suit your sailing area.
Maybe something looking a little like these but using a stayed rig:
Some good feedback here and really sound advice - thank you all!
I am Brisbane based so will be doing my sailing on sand, we have some good beaches on the big barrier islands (Stradbroke, Fraser, Moreton, Bribe etc)
Thanks SN for your offer to try out the mini, I think I might be a bit out of the way though. That said, I think I'm already sold on the LLM and have decided that this will be my first build. I will go with the surf sail, cos Gizmo is right in saying that the extra $$ is not that great and I think the simplicity of a pre-designed yacht as a first time build will be beneficial over making modifications from the first to accomodate some newbie whim.
I will not be retiring the Windrush masts back to the shed though - they will be cut down and used with stayed rigging and tailored sails. Thank you Lachlan and Geoff for your valuable insights (Lachlan - I would be part of the lynch mob for the desecration of the A class masts, if I were closer I'd be wheeling and dealing to replace my own). I think I will be getting back to both of you for more details about sail cutting and mast footings.
Will post pics as I build, still gathering info and materials for now. Thanks again for the welcome to your world and the fine advice. Anyone from South East Qld should give me a shout. It'd be nice to know who is in the area and perhaps get some feedback on our best sailing grounds.
Great choice with the Lefroy mini. Excellent little yacht, and soooooo much info for it here on the forums. Windsurf rig, some plywood and a sign post and you're half way there!
Haha - at sign-post phase now, half the fun!
Btw, how'd you find the fat tyres with the side wall distortion? Reckon they'll play along at low pressure on sand?
I haven't looked at the Lefroy mini construction pages for sometime, but since the original design there have been a couple of minor changes.
The rear of the chassis tube is plated over - seals the tube to stop gunk accumulating and rusting + it also stops stress cracking around rear welds when the tube twists.
Instead of the mast step tube being at a rearward 10 degree lean - it has been found that the mast can be much more closer to vertical [or vertical], which allows you to use an un-modified windsurfing sail.
The mast step tube needs a reinforcing strap to stop it tearing itself from the chassis tube over time.
Unless you can source a pair of lightweight balloon tyres, I would stick to the ribbed barrow tyres (I have used Mullins ribbed 4.00x8) and decent pressures. Excessive tyre distortion will slow you down too much.
+1 to SN's comments. Off the top of my head, I would also recommend 20mm bolts for axles, Nyloc nuts mean wheel/tyre changes are WAY easier than playing with pins (split, D, or otherwise) and adjustable.
Plus - don't waste your money on cheapy wheelbarrow wheels,
go straight for the Fallshaw's, they are virtually indestructible and good for over 100kph.
When my local Fallshaw dealer queried why so many were buying wheels in multiples of three, and I pointed him to youtube videos of Lefroy mini landyachts, he offered us a deal for land-yachters.
3 x wheels with the standard knobbly tyres, sealed bearings and bearing adaptors for [iirc] a bit over $115. [memory is a bit hazy on this]
I picked up the nylon bushes for the steering head from them too [either freebee or loose change]
I would run the knobbly tyres until they died, then replace them with ribbed tyres from Mullins wheels @ $16 per tyre + tube.
I too am on my first LLM. sticking primarily to plans for the first. I have read many threads concerning sails and rigging, mast angle, mast position etc etc. I know one set up will not do everything and everything a compromise. My intent is to make "fun yacht" for use on potentially soft beach sand, rather than go for maximum speed. I would like to use uncut windsurfer sails if possible for low speed and low wind speed "power". I have acquired wheelbarrow wheels, frame and steering to plans. I am thinking that a mast rake of 0 to 5 degrees best and an independent 3:1 downhaul. Comments anyone ??
Making the mast step adjustable for rake is quite easy to do and gives you options
3:1 purchase on the downhaul might be a little on the light side for windsurfer sails
Yes I considered adopting the pacific madness adjustable mast which according the plans did not look doable. From all the posts I have been able to find on uncut sails, the common thread seemed to be zero rake and lots of downhaul to get the wrinkles out. i am trying to resist the temptation of over complicating, trying to remember KISS !! keep it simple stupid !!
Select to expand quoteseabrit2 said..
... lots of downhaul to get the wrinkles out. ...
It's more like "lots of downhaul to bend the mast to match the sail's luff curve". :-)
It's a lot more than non-windsufing sailors are used to. When I was windsufing the technique to set the downhaul was to brace your feet on the bottom of the mast and pull the downhaul almost as hard as you could.
I'd suggest 6:1 is a good downhaul purchase.
It's telling that there are clam-cleat handles designed just to give better grip when pulling on a windsurfer downhaul:
There is a combo triple-block and cleat thatgives 5:1, but it works:
I'd suggest using something more like this:
Select to expand quoteseabrit2 said..
Yes I considered adopting the pacific madness adjustable mast which according the plans did not look doable. From all the posts I have been able to find on uncut sails, the common thread seemed to be zero rake and lots of downhaul to get the wrinkles out. i am trying to resist the temptation of over complicating, trying to remember KISS !! keep it simple stupid !!
Adjustable mast steps are as simple or as complicated as you like to make them. An oversize tube squashed into an oval fore and aft in a vice and welded onto the spine is as simple as it gets
I just use wedges to adjust it even drift wood pieces off the beach on occasion All the load is always back
Its handy to be able to adjust the centre of effort on these one off yachts
Like it !! Simple and effective !! Need to add a thin wall tube with greater diameter to my scrounge list !! Thankyou for the tip
Ok, cutting and welding started, the back axle is inch equivalent to the plans. For the spine I intend to use eithe 2" or 2.5" square, 0.095" wall. Thoughts ??
reading through threads uncut sails need lots of down haul, I can purchase sheeves cheaply and fabricate some triple blocks with a cam cleat.
I see a lot of posts where people use a post that the mast slips over with an aluminum mast extension. Is it possible to use uncut sails with the standard lefroy mast foot (maybe adjustable) where the mast fits inside ??
I presume with lots of downhaul with an uncut sail the sail will not weather cock around the mast since too much tension, hence using a windsurfer type down haul which rotates on the mast pin when the whole mast turns. Has anyone considered putting the lower down haul block on a strengthened mast above the conventional mast foot ?? Sail mast and pulley would rotate together even with lots of downhaul.
Round tube is better than square as it is stronger in torsion so can be lighter for the same strength
Sail and mast rotate together except where battens have to swap sides
Rotation is not much on a landyacht The apparent wind is almost always from ahead give or take a few degrees regardless of direction of travel except when you are stopped.
I find the lower end of my downhaul fixed to the yacht works ok due to this. K.I.S.S
Some prefer the fully rotating setup though
Yes it is quite ok to use uncut sails with the lefroy mast step
The lower stiffener extension tube goes straight into the step
Thanks Hiko. Just one clarification, you mention an "stiffener extension tube". Since I have aquired some broken masts, my intent was to reinforce the bottom end with two 1 metre sections of mast to make a triple wall. This would then drop into a standard lefroy mast step. Raise the turban as high as possible and maybe a top mast extension to give clearance below the sail. Is my plan flawed ??
Select to expand quoteseabrit2 said..
Thanks Hiko. Just one clarification, you mention an "stiffener extension tube". Since I have aquired some broken masts, my intent was to reinforce the bottom end with two 1 metre sections of mast to make a triple wall. This would then drop into a standard lefroy mast step. Raise the turban as high as possible and maybe a top mast extension to give clearance below the sail. Is my plan flawed ??
No Sounds good to me. 
Just a word of caution
You are aware that this activity is addictive aren,t you ?
I know everyone loves pics !! Building mostly to plans but inch equivalent here in the states. Since I want to use uncut sails I have done a version of a adjustable mast foot (thankyou to the guy in here whose idea it was but cannot find thread). Guessing about 15 hours labor in so far
