Sorry it's so late guys and Mrs Chappelow.
I did promise to post the answer today, I had visitors around so I've only just found the chance.
I've been building a pair of launching Wheels for the newly aquired SIB. I had a look around at what was for sale and was shocked at the prices
All they've stood me is £14 for the puematic jockey wheels. I sourced all the other bits from scrap Stainless 304 and 316.
To form the u bracket I found a length of unistrut (like big boys Mechano), disc cutted and angle ground the profile you see. The legs are made from thin walled 40mmx40mm stainless box section. I drilled two holes at one end on opposite sides (4 in total) and using a dremmel high speed hand held multi cutter I joined the two holes together using a mini disc cutter and then ground out the spade shape profile using a rotory file bit at 25,000 rpm.
The leg fits inside the U channel and a 6mm bolt goes though the bracket and the slotted profile in the end of the leg. This forms the hinge and locking mechanism.
The assemly was offered up to the transom of the SIB and after measuring the engine leg (longshaft) I calculated how long the leg had to be so that the wheels are longer than the outboard (that way I could deploy the wheels whilst beaching and know the outboard won't bottom out). The legs were cut to length.
I then ground out a radius to accomodate the axle tube which is 28mm diameter thin walled tubing. I then drilled though one wall, at one end using a 12mm drill. The axle and box section was then welded together with the hole facing the inside of the box section.
This is about as far as I've got so far, but the idea is to attach the bungy to the pivot bolt in the bracket and feed it down inside the leg. This will then attach though the hole and will hold the leg against the bracket under tension thus locking the leg into one of two positions (up or down).
I am also waiting for some 30mm dia washers that are being water jet cut out for me, these will go either side of the wheels and with the aid of a split pin or other locking mechanism will prevent the wheels from falling off.
Here are some pics:
1..in the raised position
2..in the down position
3..close up of the braket and hinge
....back to drawing board....
