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jhn.holgate

Project: Converting the Vmax into a landyacht

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After drooling over the MG Vertical and having had a play in the Blokart at Kingston, I thought 'well I've already got a really comfy buggy....how hard could it be to turn it into a landyacht. Like this....

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I cannot believe how similar it looks to the MG Vertical!! And didn't cost a cent.

OK, seriously, I want to be able to convert the Vmax without any drilling or alterations made to the Libre itself - bolt on, bolt off. So I made a mock-up out of whatever I could grab in the shed to test the theory of clamping the bottom and swan neck brackets on to support the mast step (the bit that the mast goes into). I'll grab some 10mm alloy plate on Monday, the proper size tube and bolts. Actually, this is the only bit (asides from the rear pulley on the boom (which I've no doubt actually has a proper name) that needs to go on the Vmax itself.

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Originally, I had a bolt going through the mast step for the brace - but that does put the mast up higher and add some weakness into the system, so I'll try some sort of bracket or clamp system. Here it's held between two bolts which apply enough pressure to assure it won't move. There will probably be plenty of leverage involved so I'll need to make sure stuff doesn't bend or brake when I tip the Vmax up (hopefully not over but it's bound to happen).

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Many thanks to Chook who's been answering my questions and casting an eye over my ideas. :good:

So, step one is to actually make the proper Mast Step which I'll get done next week.

Step two will be to get a mast and some sails. From talking to Chook and my readings of as many articles as I can, it would appear that Windsurfing sails make good landyacht sails - although in standard form, they are a bit slow from what I can gather, so they are often cut and re-sewn to give them a higher aspect ratio (I think) and more speed. A check of a couple of stores down Elwood way reveals a lot of s/h sails and masts - for a few hundred bucks, I should be able to pick up an assortment of sails and maybe a couple of masts.

Then some internal reinforcement for the mast as windsurfing masts are usually supported by the boom and windsurfer.

After that will come the boom and rigging the sail and the pulleys. And the rest of the 'unknown unkowns' :D

There's a whole world of info and terminology on sails and sailing and land yachts that I'm just beginning to scratch the surface of. Sailmaking too. I should be able to get this working for Speed Week. More to come...

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Woha.

Sounds exciting John, but that green sail is just butt ungly! Yea ya I know you are going to replace it with some thing better. Have you thought about a composite sail and make it your self? Some sort of mylar or similar non porous sheeting sandwiched inbetween ripstop nylon. All you have to do is decide what camber you want, triangulate, pring out the flat pattern and then sew up the sail.

As for the mast, I agree putting a hole at the base is bad idea, that is where the bending moments are the greatest, hence the stress peaks there. Alternatively you could make one out of wood to get a tappered mast, then wrapp some fibre glass around it with resin applied, then liberable amounts of gaffer tape while it sets. Peel off the gaffer tape, sand down and wah lah you have a fibre reinforced mast which will not crush. The wood prevents crushing, the fibre glass (hey or even get some carbon fibre) gives it bending strength.

Regards,

Norman.

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Interesting project, bring it down to speed week, see if you can Nigel proof it.

Centre of force applied will no doubt be higher than if you use a kite, that will be where the challenge will lie, so you don't up on two wheels in a gust.

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Looking the goods John. :good:

The main reason that the sails need to be strong with full length battens is, a land yacht is ALWAYS working in a head wind configuration.

Boat sails, spinnakers etc. mainly work up to the actual wind speed and then just flap about.

Soft sails don't work well on a land yacht as your dealing with very high apparent wind speeds and tremendous forces.

Our class 5 yachts have a 7 to1 ratio on the sheet rope with over 600 to 700kgs of sheet rope pressure onto the boom.

Soft sails won’t take this pressure. We need very flat (without any belly) sails that are down hauled at the front with over 100kgs of force, after the sheet rope is fully sheeted.

The last thing you want is a sail with a crease or worse still, flaps in places as this is amplified at speed.

Read that as blurred vision above 80kmh. :eek:

Windsurfer sails are built for abuse, to be lifted out of crashing waves, with lots of water over it and in the luff pocket, so they are really really strong and made of top quality materials.

Windsurfer "Race sails" are the best as they are tall and slim so your Centre of Effort is not to far to the rear.

A land yachts mast is bottom mounted and this is the main problem we have.

Windsurfer sails have the boom at chest level and out hauled to the back at this level. This is the reason that I recut the sails to 1, match the curve of the bottom mounted mast when down hauled at the front of the sail and 2, match the out haul at the back of the sail, so there are no creases with the new boom position when fully sheeted in on the rope.

I have recut over 30 now and have nearly got it right. Some need unpicking and readjusting a few times to get the creases out when they settle in.

We have an adjustable outhaul setup, made from the plastic thread of an old folding “Hills hoist”, so the belly of the sail can be removed as the speed increases.

It works like a turbo in a car, as it’s like another gear as it increases.

My 5.5 mt2 sail has got me to 123.2 kmh on Lake Lefroy. Wind was around 28knots at the time. (My mate said the wind was a bit hard to measure.)

We regularly achieve above 80 kmh with a seabreeze on our softer Pink Lake here.

2 wheels are not a problem, we can hold the wheel off for many kilometres on a steady day. It does slow you down though.

I’m loving where you are going with this John.

Look forward to your updates.

Chook “the pole dancer” :o

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All you have to do is decide what camber you want, triangulate, pring out the flat pattern and then sew up the sail.

Sounds easy. :good: er...I understand the 'sew up the sail bit', as for the triangulate, camber & pring.... :dontknow: You give me far too much credit, Norm. I may have a go a sewing up a sail somewhere down the track, but for the mo, I'll be perusing the $50 - $100 s/h sections of the board sports shops.

Only ever used fiberglass a couple of times and getting decent timber these days is very hard. I did make quite a few longbows at one stage and the only decent wood I could find was the Hickory that Sovereign Hlll uses in it's coach wheel building - they worked very well. Nah, I'll stick with s/h stuff for the mast too.

so you don't up on two wheels in a gust.

I hope sheeting out will be fast enough to cope with gusts. 15 minutes in a Blokart at Kingston was an eyeopener - particularly just how far upwind they can go.

Couple of questions I thought of for Chook - mast length - you mentioned 4.6m - is that to give us extra length to clear the boom? Would you still use that even on a 3m sail?

Also when turning - I noticed at Kingston I could turn either upwind or downwind fairly easily but was unsure whether to sheet out before the turn or not. I think I did sheet out and on one particular downwind turn the sail came around pretty quickly to take up the slack. Watching videos, it doesn't seem that there's a lot of sheeting out before a turn.... :dontknow:

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4.6mtr mast can still be used if the sail has a turban top.

This a cap made of webbing or solid plastic and then the sail is supported by cord down to the top eyelet on the sail so it can be adjusted for height by taking up the cord.

"Pin top" like most cammed sails can't be adjusted, as a pin sewn into the top of the sail that goes into a socket in the mast top. This is to act like a bearing so that they rotate easily on the mast. Usually the top of a sail reacts to a gust and it will lay off to reduce the effect of the gust to a certain extent.

Yes turning into wind is a good idea when learning as it reduces the chance of a capsize.

Turning downwind is a huge slingshot and when mastered correctly. It will set you up in the next sailing leg with very little loss of speed.

When sailing the sheet rope must NEVER go slack. So when tacking as you change direction you sheet in gently and then ease the rope back out as the sail comes over you. This eliminates the sail crack and capsize as it changes sides. Also lots of power is retained in the sail if you do this.

Sheeting out keeps the rear wheels down. The old saying "When in doubt sheet out" This also goes when trying to get moving and it's not happening in light wind. The sheet rope in long for a very good reason.

Tell tales (Bits of different coloured wool yellow one side green the other, stuck onto the both sides of the sail about 1/4 to 1/3 the way back from the mast and at 4 points up the sail) on the sail are also a must, to see if the sail is stalled or not.

80% of your sailing is monitoring these along with your apparent wind indicator.

Land yachts will sail to within 12 degrees of a head wind with speed. At about 15 degrees is where they reach their top speed.

The vertical wing (Sail) is creating some serious lift with very little drag to suck you along.

I reckon you will need 4 pulley blocks John as a minimum. 5 is better as it also pulls the front of the sail tight.

One at the bottom of the mast step, One at the front of the boom, 2 at the back of the boom and one on your seat with the end of the rope tied to your seat.

See Paul Days sketch below. He's the guru at Lake Lefroy and designed the Lake Lefroy Mini with free plans here.

http://www.seabreeze.com.au/forums/Land ... ini-Yacht/

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My mini yachts have just evolved from his basic design to suit my needs.

http://www.seabreeze.com.au/forums/Land ... roy-Minis/

:)

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Thanks Chook. I also see that windsurfers use the mast extensions with the downhaul built into it for extra length which landyachts don't? Is the downhaul covered by the way the sheet rope is run through the pulleys and attached to the boom or do you have a separate downhaul system to really yank down the leading edge of the sail?

So as for the turning, sheet out to lose some speed first and then sheet back in when you're comfy with your speed prior to turning? With the kite I can throw the bug hard upwind and/or downwind to scrub off some speed - can you still do this with the sail? Sail crack.....yep, I reckon that's what I did at Kingston.

I have rather an odd assortment of pulleys, but they'll all handle 10mm double braid (which I've got 20odd meters out in the shed) And a couple of ratshits amongst them too. :good:

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I still find it amazing the tension that these sails are cranked up to :eek: I assume (always dangerous) that the less efficiently you have the sail rigged, the slower and more flappy it will be?

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Spot on for the turn John. :)

A well setup yacht that steers just slightly into wind with your feet off the pedals on a 90 degree broad reach, will do a controlled 3 wheel drift really well into the turning marks. It's a matter of judgement of the drift. Very rarely you need to sheet out unless there is a solid obstacle behind your turning mark. Or you are really screaming along faster than 60 kmh or so.

It just costs you momentum.

To do well it’s the yacht that hold the most consistent momentum that usually wins.

If you are fast at tacking downwind, it really helps as this is the hardest leg to do well at.

Downhaul is really important here is how we do it. Lyndon Crocket came up with this magic system and it works SO well.

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Rather than tying the rope back to the mast step you can tie it straight to the ratchet block if you please. The ratchet should then jamb up against the top pulley so the sail is kept tight though.

The sail is statically down hauled then it’s tightened once again after a few minutes sailing and it’s bedded in.

The rope in this photo above, that the pulley is on is way too loose for a start. As you sheet in the downhaul is increased even further.

When the sheet rope is slack at rest, the downhaul should be like a piano string so the sail is tensioned and ready to work for you in the first puff of wind.

It also helps the battens to change sides of the mast when tacking. More so with cammed battens.

Those pulley blocks will be just the shot John. Doesn't matter how they look. My mini yacht has $450 dollars worth of "Harken" pulleys and a $110 ratchet block. I just swap them over to another mini. Oh and don't tell Mrs Chook that. :eek:

Just weld a link of chain onto the mast step to take the down haul pulley. :good:

Yeh, loose flappy sails are slow and just drive you mad after 5 minutes of sailing. Particularly the mono film sails.

You can hear them miles away. :mad:

Just watch a wind surfer down haul tension up a modern sail with the use of a hand winch onto a 6 to 1 ratio set of pulleys and then out haul the sail to remove the wrinkles.

They only get to 50 kmh or so. The force increases enormously with speed. ;)

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That's brilliant, Chook, many thanks.

Yeh, loose flappy sails are slow and just drive you mad after 5 minutes of sailing. Particularly the mono film sails.

You can hear them miles away. :mad:

Heh heh heh.....I can see some revenge coming up for Mik333 for all those times he goes past and powerslides in front of me just to add to the sandblasting effect - I'll sit behind him with a flappy sail all day. :D (if I can catch him...)

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A well setup yacht that steers just slightly into wind with your feet off the pedals on a 90 degree broad reach,

Is that called 'Weather Helm'?

Got me bits of alloy today and spent the day in the shed cutting, drilling, painting etc. Looks a little better than the four bits of wood. Still have to cut the Mast step down (it's 500mm at present and sort of looks like a mortar launcher) and I probably won't be able to flare it, but being 4mm alloy, I will file the inside lip down which will hopefully do the same job.

Next step will be a trip to Melb to source a sail and mast. btw, if a Blokart sail came up s/h at a reasonable price, would that be better?

The Mast Step base with a couple of 3mm cords looped around one of the bolts for the downhaul pulley anchor.

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Measuring up the brace...

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And painted...

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Looks a bit like a mortar launcher...

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I can vary the angle of the mast from 0 to about 12 degrees which I hope will be handy. Can't feel any flex in the mast step when I put a length of pipe in it and tip the vmax over....

Also, I think I can leave the base on permanently....it doesn't seem to get in the way and might make a cosy nook for the GPS :D

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Looks a bit better than the mock up John. :D

Might pay to flare the top of the tube to make seating the mast a bit easier if it's a snug fit.

Time to start looking for old windsurfing masts and sails.

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Is that called 'Weather Helm'?

I had never heard of that term John. I had to look it up.

The blokart sail and mast would make life easier as the sail incorporates the boom.

The fibreglass Blokart masts are very soft and forgiving in gusts to learn on and have the advantage that they pack away to just over 1 mtr lengths. A 4 or 5.5 mtr sail and mast to suit if you can find a second hand one.

If you have the coin go for it. :good:

Their masts are a bit smaller diameter as well. As you improve you can then upgrade to carbon mast sections.

A wind indicator is good to John.

Blokart make a ripper that just clips to your mast for $35.

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Construction is looking fantastic mate!!!!! :good:

The adjustable mast step will be great to shift your centre of effort when getting it set up.

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ohn you are heading down the path to the dark side,

It's Ok, I have some very bright flashlights.

Got a 4.3m Mast (nothing bigger available cheap except a one piece) and a couple of sails today (nothing big....yet...) However, haven't been able to find a suitable reinforcement for the bottom of the mast - it's 48.3mm ID according to my elcheapo calipers, but both the aluminum and the gal & black pipe I looked at where all 48.4mm OD. Ideas, Chook? My mast step is currently 500mm but I assume even at that I would need reinforcement in the mast?

Also - mast tip extensions for the bigger sails - what are the options there?

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"Also - mast tip extensions for the bigger sails - what are the options there?"

Wait till Mrs Holgate isn't looking and pinch the extensions off her vacuum cleaner!!!! :aggressive:

They work a treat as they are high tensile steel and chromed.

I have an assortment of old fibreglass feather banner advertising poles that were broken and thrown in a skip bin. They have been given new speed. Tips of broken masts and even the bottom of some surf casting fishing rods have been used on mine. Windsurfer booms are also strong aluminium to extend the masts with. Timber is ok if it's only a 150mm or so with another 100mm turned down on the lathe to go down inside the tip. When you capsize it tends to snap them off and risks ripping the sail.

All masts most definitely need internal reinforcing. The mast step socked only needs to be 250mm minimum in length so you could trim it down out of the way John.

I go 500mm more up the mast from where the step top sits on the outside of the bottom of the mast, 750mm total length. (150mm of this is the 4 fingers) these are just 4 vertical cuts from the top of the internal aluminium strengthener, evenly spaced and cut into it with the ultrafine cutting disc on the grinder, then deburred, so there is not a stress point inside the mast.

The aluminium is 48mm x 3mm that we use John. These still bend so 4mm if you can get it. Some masts are a bit smaller ID about 46mm and we use 45mm x 3mm in these. The “Roof and gutter” silicon takes up to gap and also allows the mast to still flex. Liquid nails is useless as it wont dry even after 3 months it still slipped out with the product still wet.

You can see the 8 yachts I built with the students at the Ag college a while back, here.

http://www.seabreeze.com.au/forums/Land ... M-project/

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Wait till Mrs Holgate isn't looking and pinch the extensions off her vacuum cleaner!!!!

hmmmmm.... I think Mr Holgate said he'd do the vacuuming any day now. Somehow don't think I'd get away with pinching bits of the Dyson.

Tried to get the 48 x 3 but they only had 48.4mm x 4mm - not gonna fit. Same with the gal pipe. Perhaps the mast I bought has a slightly smaller Id than most....I'll have a look in the shed and see what I've got - I think there's some wooden oars in there somewhere and a few bits of assorted pipe. If I can't find anything else, I'll get the smaller size alloy tube and perhaps sleeve it with some split plastic stormwater pipe.

I'll keep an eye out at the recycling center for any likely looking candidates.

evenly spaced and cut into it with the ultrafine cutting disc on the grinder, then deburred,

I have a little bandsaw that makes a pretty fine cut and does the top and bottom cut at the same time :D

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No it sounds like it's a standard ID size mast John, as water pipe just wont fit. Bloody close but wont do it.

Also the masts taper starts about 1000mm up them. Sometimes you have to remove the internal foam or plastic plugs some of them have 400mm or so up the base of them. A bit of sharpened rod usually does that, or drop it down from the join if it's open at the mast joint.

It's usually a 30mm thick bit of EPP foam as a plug to hold the mast round/shape when it's curved back.

Sounds like your onto it. :good:

Love your humour Clive!!!! :D

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for "roof and gutter" silicone, I use a good polyurethane sealant such as NP1 or Vulkem116. They won't sag, It's moisture cure and sets up quickly, permanently flexible, adheres well to almost anything. I don't know if it will work for your application but I'm a roofer and I know it is good stuff. Usually only available and roofing supply warehouses.

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I'll check that out ssayre. :good:

"Roof and gutter" takes so long to set in an enclosed environment. I leave it 72 hours.

Do you dampen one of the components as you fit it up, as we do when bonding foam with polyurethane glue?

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Looks good John.

Chook, it cures whether one of the surfaces is damp or not. We don't intentionally wet one of the surfaces. It draws moisture from the air. I suppose if your in a very arid climate it might need helped along. Another very good flexible adhesive/sealant is M1 from chemlink or nova link from chemlink. They cure a little faster than the polyurethane sealants. The other major advantage to all of thes sealants is they will cure all the way through without forming a skin and having an un-cured center. Roofing suppliers or concrete/masonry contractor suppliers are the best places to find these type of materials.

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Thanks ssayre. I don't use a lot of sealant anyway but always like to know about ways to improve practices. :)

That looks very nice John.

The boom will need to be at least 300mm longer than the outhaul eyelet on the sail. The bottom batten needs to clear the boom and you still have to tension the back slightly.

I make a loop from the back eyelet down to the boom and then use the end of this cord to tie it back to the rear.

Also allow for fitting larger sails so I get round with a lot of boom out the back till a decision is made where to cut it for length.

For learning John leave the outhaul fairly loose so there is a 150 to 200mm gap between the sail and the boom (belly in the sail) when viewed from the rear. This will give you more low down grunt. It's a wing so more like a transport planes wing section, high lift at lower speed.

Neil Pryde are great sails. This square high top will work a treat. Just adjust it so there is no flapping when sailing. Repeat no flapping.

What is it John. 3.5mtr???? It will be really good in high winds.

Your down haul at the front will make the mast take the shape of the sail and the front of the battens will then be in their correct position.

It's ok if the battens are pressed into the back of the mast pocket until you sheet in. So long as the front of the mast pocket is tight against the mast with downhaul it will work a treat. Looking at the picture the mast looks like it will take a really nice shape for you. It's soft enough.

If you get wrinkles in the front 1/3 of the sail, it needs more downhaul. Don't leave the downhaul too loose as it will kill the sail, as there will be too much pressure onto the front of the battens. They buckle and could snap. They also wont change sides in a tack.

A really tight downhauled sail will still need some extra sheeting in and sometimes even a slap with your hand onto the belly of the sail to get the battens to change sides in light winds. This is par for the light wind course. ;)

When you set up and are ready for some sailing practice, low speed figure 8's about 15mtrs across are the go. This helps with momentum and sheet rope handling.

Oh and the tell tales are mandatory remember.

Oh and the seat belt too, as now you have an investment you don't want to be catapulted through. The boom hurts.

Hang a 1 meter bit of ribbon or tape off the mast tip to read wind direction when learning. Its frustrating trying to get going and then realizing the wind has changed.

Just sail both ways across the wind "broad reaching" to get the hang of it.

You will be getting round on 2 wheels in less than an hour in strong winds John. :clapping:

Onya John you are in for some fun and frustration. :D

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Many thanks, Chook.

It's ready to test :good: Possible problems I foresee - not enough downhaul tension - even when I give it fairly good heave, those battens are still pretty well wedged into the side of the mast. A bit of outhaul seems to help. Also not sure about the outhaul - it seems to be pulling at 45 degrees downwards probably placing a good bit of strain on the boom - not that I've reefed it up too much. Will need longer boom and mast tip extension for anything larger - as it is, I've got enough with the 3m Revolution but would like another couple of inches for the 4.1m NP Zone - you can see in the downhaul pic that I'm getting a bit too close to the mast step.

And someone forgot about putting anti-seize on their SS bolts didn't they? :diablo: Reckon I might have to take a hacksaw to one of them. Apart from the battens being a bit pressed into the luff pocket next to the mast....it actually looks like it just might work.

I'll also try the bottom rachet pulley on one of the downhaul lines too.

On the 3m sail, I don't have the bottom batten in - I figure this might help the bottom of the sail flop to either side of the boom which it just overlaps.

BTW - here's a real beginner question for you, Chook. How do you start? Face into the wind and push yourself around till the sail starts to work? Sheeted in/out?

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PS: Andy's seat belt is back on-board :good: Hadn't though about a bit of ribbon on the top of the mast - great idea.

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