That seems to be the concencis Bob in that the mast spins on the pin and not the plate. Mine is working well in spinning on the bottom plate that the pin is welded too, but as Tom says somewhere, it would have more friction than the end of the pin and a plug spacer would be better than a washer spacer. The only reason I went a washer spacer is that it's easier to remove if it isn't right.
How are you going Aussie ? All fixed up yet ? With the measurements you gave being different again to everyone elses, it made me wonder if at the factory , after the hull is formed and mast receiver assembled, if the mast drum is glued to the mast to suit the hull dimensions. ( ie: that mast is setup for that hull ). I spose it would depend on what tolerances they could get with forming the hull.
Just a thought.
Slaughter - I haven't taken it in to the dealer yet - hopefully in the next couple of days.
I am no engineer (I know some of you are) but at the risk of being wrong, I have to say that after taking the measurements the mast clearly spins on the pin and is not supposed to bottom out meaning that it should not be touching the mast plate (hence Fusioneng's observation of no contact marks on his mast plate).
Therefore having thought about it some more I would be reluctant to place a spacer either in the mast bore hole on top of the pin or on top of the mast plate as both of these solutions will reduce the length of the pin supporting the mast inside the mast bore hole. My mast is engineered to have 18 mm of pin inside the mast bore with a 4 mm clearance between the bottom of the mast and the mast plate and if I put a 5mm spacer on top of the pin (to raise the mast the required 5mm) I reduce the support length by almost 30%. To use a spacer on top of the mast plate to raise the mast I would need a 9mm spacer (5mm plus the clearance of 4mm) which would reduce the pin length inside the mast bore by the same amount. My guess is that the pin and the hole are designed to be the length they are for a good reason and probably provide lateral support to the mast as well us vertical support (otherwise why would the hole be 18 mm - it only needs a very small pin to provide vertical support and spin). I think the pin length is also designed to stop the mast from slipping off the pin when under side pressure in strong winds.
The Hobie engineer's suggestion of packing spacers underneath the pin/mast plate (which NOHUHU also suggested on August 10th 2012) makes sense to me in that it would maintain the the pin length inside the mast bore hole and the clearance between the mast and the mast plate while successfully raising both the mast and the plate up so that the mast collar clears the roller bearing plate.
This problem, which is probably a wider one than perhaps NOHUHU realized in his post of August 10th also strongly suggests that Bob (Fusioneng) is spot on and so was Tom Kirkman in his comment on April 25th that the mast collars may be inaccurately glued on to the mast in the factory and the Hobie Quality Assurance is not detecting the error. NOHUHU discovered that adjusting the v-brace effectively lifted the whole mast receiver tube up/down "fixing" the problem but Tom confirmed for us that is not what the v-brace is there to do.
We may in fact be seeing two unrelated issues here. We could be seeing some kayaks with a mast collar gluing error and yet others may have incorrectly tensioned v-braces when leaving the factory both resulting in the mast collar rubbing on the mast bearing plate. End users are not complaining because they, like me and the Hobie dealers, do not even realize that the mast collar should not be touching the mast bearing plate and assume that as it works ok everything is just fine.
Life is the Journey - not the Destination