A little bit off topic, however What sort of tolerances are required for having wheels made?
I have worked with metal spinning quite a lot and I would have thought the process would not have been accurate enough. Usually with hand spinning on a timber pattern I would expect +/- 0.5 to 1.0mm (I'm not sure even CNC spinning would be good enough)

I must be a roughie 1mm wobble on my 26inch f/glass rims I would think was good
Imac here in NZ used to make aluminium class 5 wheels when they were 19inch
I think I dont know if they still make any Grlynch if you can make them you might be on to a winner!

Ian MacLachlan (Imac Engineering) in Palmerston North NZ made the 19" and 26" aluminum wheels. Not sure if he made them for the French but I know he sent quite a few over to the UK. Unfortunately Ian has wound up his engineering business and is now teaching engineering at a polytech in New Plymouth NZ. Unfortunate for us but good news for his students as Ian is an exceptionally clever engineer. The disks were spun up against a solid steel mould. The rim was rolled out of flat sheet and somehow folded over the edge of the disks. The hubs were welded in last. I dont know how he did it but they were all damn near perfect. One of his YOTTs is up for sale now. (see pic below). Not sure if it comes with 19" or the 26" wheels as in the photo. If anyone is interested send me a PM and I will give you Ian's email address. I dont know the price.

I checked my fiberglass wheels today, They are just under 1/8" out of round, I don't notice it at all when I am sailing. The wheels have held together well and have done some hard racing, They have cost me around $50 to $60 each to make, they weigh 3.5kg with the Tyre. I am going to make a couple more soon so I will take pics and notes and post on here as I go. Have improved on the first ones I made. I think I have overcome the problems I had with the first pair
www.seabreeze.com.au/forums/Land-Yacht-Sailing/Construction/Building-new-class-5/
Cheers
aus230

Seagull makes the 26inch wheels 291,02 euros without bearings, FOB France according to matthieu@seagull.fr yesterday. I have inquired about IMAC wheels a couple of times in the last few years and never got an answer.
Blake

blake52 said...

Seagull makes the 26inch wheels 291,02 euros without bearings, FOB France according to matthieu@seagull.fr yesterday. I have inquired about IMAC wheels a couple of times in the last few years and never got an answer.
Blake

291 euro! Thats NZ$520 at todays rate. The Imac 19" were NZ$350+tax each but that was over 10yrs ago. They would be at least $500 now. They weigh 4.5kg. The 26" probably weigh 5kg. Yes fibreglass sounds like the way to go if you have the time and the skills.
I guess Class 5 is more suited to the design and build type blokes. That's what attracted me to the class. Warning! It can become an addition once you get into it.
Nice 3D Blake. That's pretty much the plan I am working on. What cad program are you using?

You must have esp Blake. This is the plan I was working on last night.
Note I have moved the mast post slightly forward from the last sketch.
The main steel frame will sit flat on a bench when turned upside-down.
Makes it easy to make a temporary welding jig like I did with the Mini.
How do you like the new name?

Yes, the adjustable mast rake is the important thing. It doesn't really matter where the mast is attached, to a point, as long as you can adjust the rake to bring the center of effort of the sail over the center of where you feel balanced. The old sail I built the yacht for had a shorter foot than the one I am using now. I find the new one needs to be positioned further forward so I can position the pulleys on the boom further back and get more leach tension. The newer sails seem to be designed to be raked back quite a bit. Narrow at the top and a long foot. Could this be for higher speeds?

aus230 said...

clem
does that mean if the back wheels are breaking away a bit the mast should be stood up a bit?

Yes, more than likely...but if the wind is up and you're light like me, you may need to also add some more weight to hold it down .

I am not sure if that setup is within the class5 rules safety wise
It would seem to me that hitting something would give you a full facial with the end of the boom

Hiko said...

I am not sure if that setup is within the class5 rules safety wise
It would seem to me that hitting something would give you a full facial with the end of the boom

I wouldn't worry too much about that happening. The end of the boom is all-ways slightly off to the side anyway, and those guys never crash.... they just win the races.

Sorry I disagree The boom is not always off to the side especially when tacking or gybing secondly a front on impact would most likely pivot the torso upward putting the end of a short boom right in the face
Regardless of any rules it looks a hazard to me having a boom that short
It is quite conceivable that an impact could swing the yacht and the boom
creating a danger to the head even if the boom was off to the side originally

Yes you are right if we wanted total safety we wouldnt do much at all
and even then we wouldnt be
Not that keen on looking for trouble though I hate pain-- it hurts

that boom position lets you know your finally starting to build a decently fast class 5
mind you at least ive got a seatbelt. the lowest this boom will go is 460mm, with an eye level of 400mm( got checked earlier this year)

I have wondered about those nose fairings...my feet, which the rules say have to be visible from above go way forward of the Y on my Rocket YOTT. Maybe the Y is further forward on the French boats. I found a mast top photo of a Plume yacht, I think from the Worlds in Argentina. Feet just visible. I'm searching for a similar photo of a British YOTT boat.