I've Just had a real scary moment working on my MAC
I keep my M26 nicely sheltered in a horse paddock.
I was doing a pre season check of brakes/ bearing when I noticed some tyes were starting to splitt - More expense :cry:
The local tyre dealer gave a very good deal for a set of four so I put the trailer on axle stands , 4 wheels off and away downtown i went.
Returning with 4 shiney new tyres a few hours later I went to fit them.
I placed 2 tyres against the trailer and watched in Horror as SLOWLY ALL FOUR AXLE STANDS GENTLY ROLLED OVER in the soft earth !
The Mac and trailer were gently deposited 18 inches stb on the hubs .
NO Damage - Thank goodness but it took 2 hours of carefull jacking to get it back on its wheels.
Lessons learned-
1. A field may look hard but in spring it isn't
2. work on a hardstanding - It's much safer and cleaner .
3. When jacked up the mac trailer is unstable it can easily rotate around the nose jack.
4. When working on the trailer tilt the outboard up, with no wheels the outboard will touch the ground (no damage this time!)
I'm getting a set of these for the winter also http://www.ebay.co.uk/itm/Pyramid-Caravan-Trailer-Winter-Security-Storage-Wheels-Pair-/260857205387?pt=UK_Campervan_Caravan_Accessories&hash=item3cbc4d128b
It's better to soar with the eagles than scratch with the chickens

Another good tactic for working on the trailer is do it while the boat's floating safely on a mooring. :-)
That's what I'm about to do with mine, although I appreciate it's not always possible for everyone.
Rick Jones (Treasurer), former 26X & 19 owner, Isle of Wight
those things are good!
after forking out for those damn hi press tyres, it is worth bearing in mind that leaving them loaded in the sun will destroy the rubber quicker than wear.
In theory, there is no difference between theory and practice; In practice, there is.