Final Update.
The stainless M6/M8 channel nuts arrived and I hunted up some larger stronger square washers so it's all stainless materials now with the aluminium bar. I ordered the channel nuts through an electrical wholesaler as they are a Unistrut/Ezystrut accessory. The original channel nuts (zinc) were showing signs of rust (at top of pic).
I also sourced a better fitting for the boathook. This doesn't twist when you move the handle.
I also added some 50mm webbing and a quick release clip to hold the cart securely to the hull.
If you need front hatch space you can store the cradle on the rear deck once the wheels/axles are removed and stored in the front hatch.
This cart has now become my favourite for moving the TI. It supports the hull well, breaks down quickly and is so easy to fit when retrieving the TI. Just slide it under and strap it.
So much better than the scupper cart!
Did I say that?!
PS:
This hasn't been a cheap mod. The Hobie cradles are $240/pair (though that's a much better price then the $420 I paid for exactly the same cradles when I first got the TI!
)
The cost breakdown is roughly as follows:
Rhino bar 1m $25
Cradle $120
Channel nuts 11@ $4 = $44
M6 Collared Eye bolts 4@ $5 = $20
16mm SS axles $12
Other stainless fittings/bolts/washers etc $30
HD foam wheels $60.
So all up over $300 in materials. It was easy to assemble though, as it all just bolts together, so no welding necessary.
I'm sure Hobie are missing a marketing opportunity by not providing a more portable and convenient dolly cart for the TI!