Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.
John, as Arlyn commented also, seems you have nothing to loose as you intend to get the marina to try fix it. I would go out there, and give that messenger line a tug hard enough to break it! Either the ferrule will exit the top or the line will break($5.00 for a better line). Make sure the tug is aimed directly down the furler extrusion so as not to tempt the ferrule out of it's groove. Just wrap the messenger line around the bilge pump handle (or bit of boom stick) so that you have a really good purchase, then <u><i><b>TUG!</b></i></u>
As far as lowering the mast: yes, the trailer assist is great, but I would not hessitate to lower your mast on the water.
Remove the boom, attach the baby stays.
Drop the keel to fully lowered.
Use the Jib Halyard and the main halyard (belt and braces) and secure them to a line (3/8") through a block attached to the bow plate and ran back around a winch (but not tailed) (just use the winch as a friction device, have crew to ease the line on the winch.
Make sure both halyards are made secure at the mast.
Enlist the aid of a couple of strong adults.
You'll be amazed how easy it is. don't forget to put the aft mast cradle in place. The only thing to pay additional attention to is the boat balance, tell the crew to get in place and stay in place, no point in scaring the ^%$^0 out of everyone by causing the boat to heel.
When the mast is down, you'll need to unstep it and move it forwards, unless the boat is backed into your slip and you can reach the masthead from the shore/jetty. If you do have to unstep it. Place a fat fender just aft of the maststep, it'll act as a suspension unit and make it easy to withdraw the bolt from the mastfoot.
Notice: The advice given on this site is based upon individual or quoted experience, yours may differ. The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.