This build started at the end of 2016 after watching a few french class 5 videos.





The next question was how much do these cost and where do I get one??

www.charavoile-amx.fr/index.htm
plumefactory.fr/
www.seagull.fr/

Wow!! almost 7000 Euro for a class 5 without wheels.

How about a second hand one to refurbish?? Some are 2-3K Euros

I have the materials, I have the time and I have the skills and my degree from the Landyacht university I can make one. If I have pictures I can make it.

Next question was what design?? Most Euro yachts are Y frame over the top.

I have been fortunate enough to sail in AUS230 yacht and like the way that it performed so a similar design is what I settled for.

Which yachts and which pilots are the fastest??
In Europe you have the MORANDI?RE brothers at AMX and Fran?ois Papon F225 are the top guys.

F225 Posted these plans on french class 5 forum and these have been posted on seabreeze in previous posts.















These plans were a good starting point and I'm sure the devil is in the detail.

Here were some pictures of the details that I found useful.










After studying pictures and various sketches it was time to Just F@#%ing Do It.

Here is how it went down.
















Rear Stub Axles at 10degrees

Steering head angle 70degrees and 70degrees

I suspect I will have to move the seat back. Front wheel weight is 20kg and goes up to 21kg when Im in it. Could probably move seat back 250-260mm.

Standart type sheeting is ok but needs to come further back. Needs to be 2/3 back from mast now probably at 1/2 way.

Set Up Questions:
- How much weight should be on front wheel for class 5? ( I think mini is about 8kg?? not sure about class 5)

More to come.

Ben.

Great looking build so far! Frame looks excellent. On my class 5 NZ Rocket and Fed 5 mini 6.7, I use center sheeting with triple blocks. The block at the boom is slid forward or aft until the sail reacts like I want. Aft pushes boom toward mast creating more pocket, forward pulls boom aft flattening sail more. It also depends on where the lower triple is connected. I have 10 lbs (5kg) inside the front tube just behind the steering head on my Fed 5. That seems to work well for me. I doubt there is a set weight for any class or boat. It's more likely tailored to what YOU need to balance out the boat. I tried different weights before settling on what I use now. Once you get your seat placement sorted you can begin finding that perfect balance. Again, that frame looks really good. I hope to learn to weld that good someday! How bad did it hurt your brain to figure the angles on the steering?

Nice work Ben!!!!!

I had another look at the class 5 today.

Whenever I build I aim to keep construction as clean as possible. KIC (keep it clean) However this in not entirely possible when you have no detailed plans and just making it up as you go.

US723 to get better welding just burn plenty of electrodes. Probably used over 10kg in the last several years.
Remember one bead at a time. Then repeat hundreds of times.

Steering was what "looked" right. As long as the centre line of the pivot bolt met the contact patch I knew the steering was good. However this set up looks similar to the old toranas where they collapse on itself so had to weld some steering stops.

Moved the seat back 250mm and got some new measurements.
14kg on front wheel unladen
11kg with me in it sheeted in.

Not to worried if need more weight at the front will probably sandbag front of seat or cast some lead donuts for front axle.

Scrapped "Standart" Type sheeting in favour of triples and ratchet block.

Next week off lots planned hopefully a test sail and break something.

Cheers

Ben
AUS233

Class 5 is ready for a test sail.

It will be interesting to see how it performs.

I'm sure there will be some tuning that needs to happen.

Once I am satisfied with performance and reliability I will modify the seat and repaint.

Will report back after testing.

Ben.

Select to expand quote

BenBoulder said..

Looking good!!

love the colour - very XU1 Torana-ish

Looking forward to seeing how it goes. That is one nice looking yacht!

Maiden voyage for the class 5 today.

Conditions were less than ideal(cold, wet, inconsistent wind) however was able to give the yacht a proper shake down.

The yacht felt balanced, accelerated nicely,was stable at speed, turned nicely and the 8ball shifter/tiller helped for running push starts.

I was happy that all system worked.

Next phase is to give the seat a nose job to clean up the aerodynamics as well as a few cosmetic changes. (More pink I think hahaha.)

Looks brilliant Ben!!! Really nice job.

After 6 months my "Dulux hot pink" painted mini turned red after it's exposure to Lefroy's salt. Not sure what happened there.

I see Bryan was celebrating early, their 7/1 win in the Americas Cup with his New Zealand flag flying there.

Good job on the yacht
A lot of good ideas built in to that package

Class 5 ideas.
I like the idea of the bumpy moulding under the clew rope eliminating the need for an outhaul.

Seagul make a nice class 5 sail.

AMX aren't bad either.



My class 5 is ok for 100km/h but many small refinements can be made.

Class 5 ideas.
I like the idea of the bumpy moulding under the clew rope eliminating the need for an outhaul.

Seagul make a nice class 5 sail.

AMX aren't bad either.



My class 5 is ok for 100km/h but many small refinements can be made.

Great build thread!

Racing Action

Yacht competed in first Regatta.

Day 1 Race 3 Axle snapped. Overnight repair had yacht ready for day 2.

Yacht was smooth, powerful, pointed high and had good speed. No more breakages.

More racing action and equipment testing.

4.6m Sail works well in strong breeze.



If you butt join your axle using three pieces of steel to make one long piece ensure you don't grind your welds and include an internal sleeve.

Modified (soft) battens out on the salt make the sail more efficient.



Snapped axle put back in to limp home.