I haven't heard anything about problems associated with temperature extremes, but...
In the photos to which you linked, I see a trailer entirely unsuited to the boat it is supporting (not to mention the load of snow/ice). Even with the limited rocker/hull curvature, the two straight, flat trailer bunks cannot provide more than a few square inches of contact surface between the bunks and the hull.
A boat this size and weight should have athwartship, rather than fore and aft, trailer bunks which would provide far more contact and load bearing surface area. And, there should be at least four such bunks to adequately distribute the weight of the hull as well as the shock loads incurred while trailering. Ideally, those bunks would be spaced out fore and aft and aligned under structural bulkheads or other reinforced areas of the hull.
I would be amazed if this is the trailer and bunk system that Hunter provided with this sailboat. If it is, then Hunter should step up and help you out with repairs (assuming you are original owner). If it isn't, and Hunter never approved this trailer for use with their boat, then you would be well advised to gratefully accept any assistance they offer.
Hunter has already offered to fix his hull, which is nine years old, four years out of warranty. These boats cannot withstand storage in extreme temeperature swings due to the hull composition on the 170's and is stated in their manual.
Last edited by scottbr; 10-31-2009 at 08:36 AM.