US772 said..

I would go aero first. Then see what happens. If it's too stiff taper slightly and re aero shape.

aus230 said..

thanks Kiwi,
I am going to use a snubbing winch.

Today I tapered the plank from 60mm in the center down to 36mm on the ends and rounded the edges. I am only getting 20mm deflection on the plank when I put 90kg in the center, I don't think this is enough should I taper some more or shape to a more aero foil shape until I get some movement.(it bends more when I jump on it)

Part of the reason that the European guys tend to use straight timber (normally quarter sawn ash) is that you can plane it, and glue bits on to tune. Once you go the composite, or glass over timber, you are about stuffed (or committed). One of the favourite sayings over there was "The yacht must answer the conditions". So if it was rock hard (US desert for example) you could be much stiffer, ripply soggy euro beaches need to be softer. Steady winds and gusty also need a response. Most of the top euro guys I knew carried a power planer with them and first night after practice was noisy (or epoxy smelly). This was guys who had sailed all year, but were at another venue. Not uncommon to be carrying 3 axles on the trailer.
I can not understand how you could make a definitive, for example 100mm of bend for 100kg unless you know the span of the axle. Mine, as in the avatar, went like a slug after I sold the good axle, and took almost a solid year to get close to where it had been, and it was only a plank of bloody wood!

I guess what you guys are saying is leave it as is until I sail it.
Not sure if I did this deflection thing right but came to the measurement by having the ends of the plank supported on bricks , then measuring the distance to the floor in the center of the plank to the ground. To read the bend I added a 100kg to the center and measured the distance again,there was about 20mm difference between measurements.

The axle is 3 layers of 20mm x 200mm bonded together as per the US277 video. It is tazzi oak. and shaped the same.
It will only be sailed on Lefroy which is a hard salt lake, any where else it sails will be similar (lake Wallyungup)
I will get a couple of pics up today(dam camera decided to go on strike)
? am I measuring the bend right.

nice work Vic

looking stunning Vic

It was always going to be black, The plank will be clear coated wood

aus230 said..

It was always going to be black, The plank will be clear coated wood

"Vic T My Eyes"

Be a wee bit careful with timber laminate, epoxy construction and BLACK. You may have epoxy degradation in the heat and high UV of the Oz summer.

Still waiting for the wheels to arrive. Then I can fix the wheels to the axle ,in the meantime I have the hull just about ready for painting,the steering gear has been installed(6" of adjustment forward and back).
Once the body is on the plank I can start of the front (wheel/steering) I think I will have to wait for the back wheels to be installed and the body sitting on the plank to get the steering pin angle right.

Wheels arrived. Have to make axles now
Can anyone tell me if the front wheel is a wheel barrow type or will a farshaw be OK. or does it need a better quality wheel.

Thanks Clem,
Lathed up the axles today. Worked out OK, first go at making something like that Made them out of hydraulic ram rod,Of a cat bogger. Might make another set out of an old truck axle.

How much heat Chook.

re the front wheel, i reckon the fallshaw would be fine , be sure to balance. the tyre will last along time,if you have the balance right. i reckon they have proved themselves to be tough enough

If your MIG is up to the task, has enough amps, it is a low hydrogen process due to the shielding with an inert gas. (it does depend on the wire though)
You will be welding it to mild steel flat bar or plate I'm guessing, so "general purpose" wire will be ok.

Just turn your gas flow rate up, to make sure it isn't interrupted by a breeze on really critical welds.

I'm a tight arse and do 99% of my welding inside my shed, so only use 7 to 10 litres per minute flow of "BOC Argoshield Universal" in my draft free area on mild steels. I turn this up to 20 Lpm for important jobs.

Thanks Chook, I did not know about pre heating and I had forgot about cooling in lime(something that I learn't about in metal work classes at school which was a long time ago)

Thanks Bill, do you have a pic of your Sanderling don't I have seen it.

Front steering assembly and rear axle attachment designs I will use pics kindly supplied be Airtrack