Forums > Land Yacht Sailing Construction

New build LLM/Seagull Silence bitza

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Created by ELM 28 days ago, 23 Oct 2017
ELM
VIC, 4 posts
23 Oct 2017 7:10PM
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Ok, well first of all; g'day to all, new to the site (well was sure I joined many years ago but dropped off radar many years ago) and my (questionable) first post.
Close mate of mine (Cob, as in Cobber), whom bought a Hobie Adventure Island (sailing tri hull kayak) from me. Found in hard street rubbish (what a great service and supply source (looking around innocently) a 4.8m mast + sail from a wind surfer, and has asked if I could help him build a land yacht.
With no hard plans to work off, just a mast and sail, it was off to WWW to see if I could find some info, plus some simple plans to work off. Of course, these would also be limited to availability of salvaged materials, a very limited budget and hopefully advise/input from members here with the experience and knowledge.
Now a machine that has really caught my eye, is the "Seagull Silence" (no plans available), and with the Lake Lefroy Mini (LLM) (which there seams to be plenty of info + plans available here on Seabreeze) similar in size, I thought I might be able to use the overall length/width + angles etc to build a frame similar to the Seagull.
Main reason I am leaning towards the Seagull styled frame, is the light gauge salvaged steel I have on hand. It's 1.5mm x 42mm diam gal tube from a circular trampoline frame, Please don't hold back, open to all comments
My two main concerns are:
(1) the light gauge
(2) the punctures along the steel lengths, where the springs were inserted.
Main reasons to use this steel:
(1) the light weight
(2) to make use of the nice curves
(2) to use perforations and springs, to make a trampoline style seat base, inside the frame
(3) gal protection.

Steering: I am hoping to use the steering neck from a salvaged bmx, will remove the bearings and replace them with bushes machined down from either polyurethane skateboard wheels or old nylon wheel salvaged from abattoir carcass hooks.
While on the subject of steering, I have read that suspension softens the performance of a land yacht; is that aimed more towards rear suspension which I am guessing bears most of the wind load?
While a completely different designed land yacht to an LLM etc, I note the good experiences of AUS230 with front suspension here. I am curious if anyone has tried, or has an opinion about Girder fork or Front Link suspension on the front of a smaller land yacht?
I guess it is also worth mentioning/asking now, as I have mentioned suspension. I think it was Gizmo who tried using ski's as a rear axle, found 1 set was too soft, so doubled up with a second set. Since reading the thread when I first started my search, I have not been able to find the thread nor the outcome of his experiment. Would love it if someone can reacquaint me with the thread, or if Gizmo can chime in with his findings.
Well I guess that will do for a start and thanks in advance for any help/advise.

Hiko
1155 posts
24 Oct 2017 2:45AM
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Hi Welcome to the forum
I have built two mini size yachts with ski axles at the rear
They work fine doubled up face to face
I believe a single ski would work fine on the front also but have not tried that
The tramp tubes should work OK I think if you get the design right and the welding is good on the light tube
I would suggest the welding should be purge welded Tig to get the best results
Good luck with it and keep us posted !

ELM
VIC, 4 posts
24 Oct 2017 1:45PM
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Gday Hiko and thanks for the reply.
Could you tell me if you glued the two ski's together or just clamped.
Not sure if it is overkill, but I have been toying with the idea of fix mount the bottom ski, then with use of a spacer (at the mount) and slotting the top ski so it can then move in/out. Would then weld stub axle to to two pin shackles and that way could adjust wheel camber if needed. To help stop the top ski from moving, I thought a full thread bolt with a tube nut could be dropped into slotted ski between the fixing bolt, that way (while fiddly) the bolt/nut could be adjusted in length and the ski under load, could not be pushed inwards adjusting the camber.
Any thoughts?

I never thought of a ski up front, you may have something there!

As for the TIG welding, buying a good tig does not make thy a good welder. Will do my best. One thing for sure, will need to clean prep well and weld with good ventilation. Can think of better things than welding gal.

Bynorthsea
70 posts
24 Oct 2017 3:37PM
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Have a look in my album there is some photos of my ski set up which I've used successfully for many years

Hiko
1155 posts
24 Oct 2017 4:53PM
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Hi Elm
My two ski minis have the axles held on the inboard end with two 10mm studs welded to the chassis and the axles held with two flange nuts each side The outboard ends have stub axles welded to a plate and two 8mm setscrews pass through a plate underneath through the skis and are tapped into the top plate and stubaxle which is one welded unit
Hope this makes sense. All fastenings are along the length of the skis.
The skis are permanently joined together at the stubaxles but are only held together at the chassis when they are mounted They work exceptionally well and give just the right amount of flex for me [around 100kg] but would suit a wide range of weight I think
They have been on there around 8 years now
I did originally try a single ski but it proved to have too much flex
Cheers Hiko

ELM
VIC, 4 posts
25 Oct 2017 2:21PM
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Nice of you to drop in Bynorthsea and thanks I did drop into your album for a look at Willow, looks a good sturdy machine. Are they aircraft tyres on the rear?

G'day again Hiko and thanks for your description of mounting. WoW 8 years they really stand up to it then and using ski's looks very appealing now. Certainly better than steel .

I started reading the sail making section yesterday, strewth most of that went over my head like it came out a 50cal. I have only seen a photo of the mast and sheet, not sure if he has the windsurfer boom or if we have to make one. Looks like it will be interesting times coming that's for sure.

Anyway, have a good one guys and chat later, ELM

Bynorthsea
70 posts
26 Oct 2017 2:48AM
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For the beach I'm set up with 20 x12 slicks, not quite as fast as wheel barrow wheels but I can keep going in the wet and soft stuff. I have had the tyres a long time as they just don't wear on the beach, I think they are sold as all terrain buggy tyres.

ELM
VIC, 4 posts
26 Oct 2017 10:50PM
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Yes ok, not even sure where one can be used here on the Peninsula yet, plenty of soft rough beaches. A lot of beaches down here come under National Parks, so assume they will be out, plenty of car parks, other than that, try and find a paddock somewhere (be nice to get on a golf club).
Guess we need to look into that a bit more, so we have an idea about wheels/tires.
Regards ELM



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"New build LLM/Seagull Silence bitza" started by ELM